Mary Leonard, M.D., M.S.C.E., Arline and Pete Harman Professor and Chair, Department of Pediatrics

All Publications

Estimation of Skeletal Muscle Mass Relative to Adiposity Improves Prediction of Physical Performance and Incident Disability JOURNALS OF GERONTOLOGY SERIES A-BIOLOGICAL SCIENCES AND MEDICAL SCIENCES Baker, J. F., Long, J., Leonard, M. B., Harris, T., Delmonico, M. J., Santanasto, A., Satterfield, S., Zemel, B., Weber, D. R. 2018; 73 (7): 946–52
Abstract

We assessed the discrimination of lean mass estimates that have been adjusted for adiposity for physical functioning deficits and prediction of incident disability.Included were 2,846 participants from the Health, Aging and Body Composition Study with available whole-body dual energy absorptiometry measures of appendicular lean mass index (ALMI, kg/m2) and fat mass index (FMI, kg/m2). Age-, sex-, and race-specific Z-Scores and T-Scores were determined by comparison to published reference ranges. ALMI values were adjusted for FMI (ALMIFMI) using a novel published method. Sex-stratified analyses assessed associations between lean mass estimates and the physical performance score, ability to complete a 400-meter walk, grip strength, and incident disability. Dichotomized definitions of low lean for age and sarcopenia were examined and their performance compared to the ALM-to-BMI ratio.Compared to ALMI T-Scores and Z-Scores, the ALMIFMI scores demonstrated stronger associations with physical functioning, and were similarly associated with grip strength. Greater FMI Z-Scores and T-Scores were associated with poor physical functioning and incident disability. Definitions of low lean for age and sarcopenia using ALMIFMI (compared to ALMI) better discriminated those with poor physical functioning and a greater risk of incident disability. The ALM-to-BMI ratio was modestly associated with grip strength and physical performance, but was not associated with completion of the 400-meter walk or incident disability, independent of adiposity and height.Estimation of skeletal muscle mass relative to adiposity improves correlations with physical performance and prediction of incident disability suggesting it is an informative outcome for clinical studies.

View details for DOI 10.1093/gerona/glx064

View details for Web of Science ID 000435469200014

View details for PubMedID 28958026

View details for PubMedCentralID PMC6001879
Changes in pediatric DXA measures of musculoskeletal outcomes and correlation with quantitative CT following treatment of acute lymphoblastic leukemia BONE Mostoufi-Moab, S., Kelly, A., Mitchell, J. A., Baker, J., Zemel, B. S., Brodsky, J., Long, J., Leonard, M. B. 2018; 112: 128–35
Abstract

We previously reported significant gains in pQCT measures of tibia trabecular bone mineral density (BMD) and cortical structure following completion of therapy in children and adolescents with acute lymphoblastic leukemia (ALL). The objective of this study was to examine changes in DXA measures used in clinical practice and expressed as Z-scores using robust national reference data. Children and adolescents, ages 5 to 18 years were enrolled within 2 (median 0.8) years of completing ALL therapy. DXA total-body less-head bone mineral content (TBLH-BMC), and spine, total hip, femoral neck, and 1/3rd radius areal BMD (aBMD) were assessed in 45 participants at enrollment and 12-months later. Linear regression models examined correlates of changes in DXA Z-scores. Changes in DXA outcomes were compared to changes in tibia pQCT trabecular and cortical volumetric BMD (vBMD) and cortical area. At enrollment, DXA TBLH-BMC, spine and radius aBMD Z-scores were not significantly reduced in ALL survivors; however, total hip [median -0.74 (IQ range -1.51 to -0.04)] and femoral neck [-0.51 (-1.24 to 0.14)] aBMD Z-scores were lower (both p < 0.01) compared to reference data. DXA Z-scores at all skeletal sites increased over 12 months. Despite improvement, total hip Z-score remained lower at -0.55 (-1.05 to 0.18). The increases in TBLH-BMC, total hip and femoral neck aBMD Z-scores were more pronounced in those enrolled within 6 months of completing ALL therapy, compared to those enrolled at >6 months. Gains in TBLH-BMC, total hip, femoral neck and radius aBMD Z-scores were significantly associated with gains in tibia cortical area Z-scores (R = 0.56 to 0.67, p ≤ 0.001). Changes in TBLH and proximal femur sites were associated with gains in trabecular vBMD Z-scores (R = 0.37 to 0.40; p ≤ 0.01); these associations were not significant when adjusted for gains in cortical area. In summary, gains in DXA measures were most pronounced in total hip and femoral neck following ALL therapy. The gains in all DXA measures, with the exception of lumbar spine, reflected gains in cortical area. Overall, ALL survivors demonstrate skeletal recovery following completion of therapy; a small sub-group continue to demonstrate deficits and benefit from continued observation to ensure improvement over time.

View details for DOI 10.1016/j.bone.2018.04.012

View details for Web of Science ID 000434371100014

View details for PubMedID 29679731

View details for PubMedCentralID PMC5970089
Associations between exercise, bone mineral density, and body composition in adolescents with anorexia nervosa. Eating and weight disorders : EWD Nagata, J. M., Carlson, J. L., Golden, N. H., Murray, S. B., Long, J., Leonard, M. B., Peebles, R. 2018
Abstract

OBJECTIVE: To identify the effect of duration of weight-bearing exercise and team sports participation on bone mineral density (BMD) and body composition among adolescents with anorexia nervosa (AN).METHOD: We retrospectively reviewed electronic medical records of all patients 9-20years old with a DSM-5 diagnosis of AN evaluated by the Stanford Eating Disorders Program (1997-2011) who underwent dual-energy X-ray absorptiometry.RESULTS: A total of 188 adolescents with AN were included (178 females and 10 males). Using multivariate linear regression, duration of weight-bearing exercise (B=0.15, p=0.005) and participation in team sports (B=0.53, p=0.001) were associated with higher BMD at the hip and team sports (B=0.39, p=0.006) were associated with higher whole body BMC, controlling for covariates. Participation in team sports (B=-1.06, p=0.007) was associated with greater deficits in FMI Z-score. LBMI Z-score was positively associated with duration of weight-bearing exercise (B=0.10, p=0.018) and may explain the relationship between exercise and bone outcomes.CONCLUSION: Duration of weight-bearing exercise and team sports participation may be protective of BMD at the hip and whole body BMC, while participation in team sports was associated with greater FMI deficits among adolescents with AN.LEVEL OF EVIDENCE: Level V, descriptive retrospectivestudy.

View details for DOI 10.1007/s40519-018-0521-2

View details for PubMedID 29949128
The Association of Diet and Exercise With Body Composition in Pediatric Crohn's Disease INFLAMMATORY BOWEL DISEASES Lee, D., Lewis, J. D., Shults, J., Baldassano, R. N., Long, J., Herskovitz, R., Zemel, B., Leonard, M. B. 2018; 24 (6): 1368–75
Abstract

In pediatric Crohn's disease, fat mass improves over time with treatment, but lean mass deficits persist. This observational study of the associations of physical activity and dietary intake with lean mass and muscle strength in children with Crohn's disease was ancillary to a previously reported randomized clinical trial of an intervention to improve bone health.In this study, 138 participants were followed at baseline and at 6, 12, and 24 months with evaluation of lean and fat mass using DXA, muscle strength (peak torque), Crohn's characteristics, dietary intake, time in moderate to vigorous physical activity (MVPA), and serum insulin-like growth factor-1 (IGF-1) and tumor necrosis factor-alpha (TNF-α). Race- and sex-specific Z-scores for leg lean mass and whole body fat mass were generated. Quasi least square regression evaluated determinants of changes in body composition and muscle strength.Leg lean mass and muscle strength were positively associated with time in MVPA (P < 0.05) and negatively associated with increasing clinical disease activity (P < 0.05). Both leg lean mass and strength were positively associated with IGF-1 Z-score (P ≤ 0.03) but negatively associated with serum TNF-α (P ≤ 0.04). Neither lean mass nor muscle strength was associated with caloric or protein intake.Persistence of lean mass deficits was related to ongoing Crohn's disease activity but improved with greater time spent in moderate to vigorous physical activity. Future trials are needed to evaluate the efficacy of physical activity in improving lean mass in pediatric Crohn's disease.

View details for DOI 10.1093/ibd/izy024

View details for Web of Science ID 000432697200029

View details for PubMedID 29718224
Leg lean mass correlates with exercise systemic output in young Fontan patients HEART Avitabile, C. M., Goldberg, D. J., Leonard, M. B., Wei, Z., Tang, E., Paridon, S. M., Yoganathan, A. P., Fogel, M. A., Whitehead, K. K. 2018; 104 (8): 680–84
Abstract

We previously described lower leg lean mass Z-scores (LLMZ) in Fontan patients associated with worse peak oxygen consumption on metabolic exercise testing. We hypothesised that LLMZ correlates with indexed systemic flow (Qsi) and cardiac index (CI) on exercise cardiac magnetic resonance (eCMR).Thirteen patients had LLM measured by dual-energy X-ray absorptiometry within mean 40 (range 0-258) days of eCMR. LLM was converted to sex and race-specific Z-scores based on healthy reference data. Ventricular volumes and flow measurements of the ascending and descending (DAO) aorta and superior vena cava (SVC) were obtained by CMR at rest and just after supine ergometer exercise to a heart rate associated with anaerobic threshold on prior exercise test. Baseline and peak exercise measures of Qsi (SVC+DAO/BSA) and CI, as well as change in Qsi and CI with exercise, were compared with LLMZ by linear regression.LLMZ was not correlated with resting flows, stroke volume or CI. There was a strong linear correlation between LLMZ and change in both CI (r=0.77, p=0.002) and Qsi (r=0.73, p=0.005) from rest to exercise. There was also a significant correlation between LLMZ and Qsi at exercise (r=0.70, p=0.008). The correlation between LLMZ and CI at exercise did not reach significance (r=0.3, p=0.07).In our cohort, there was a strong linear correlation between LLMZ and change in both CI and Qsi from rest to exercise, suggesting that Fontan patients with higher LLMZ may be better able to augment systemic output during exercise, improving performance.

View details for DOI 10.1136/heartjnl-2017-311661

View details for Web of Science ID 000429733300012

View details for PubMedID 28988207
Diagnosis, Evaluation, Prevention, and Treatment of Chronic Kidney Disease-Mineral and Bone Disorder: Synopsis of the Kidney Disease: Improving Global Outcomes 2017 Clinical Practice Guideline Update ANNALS OF INTERNAL MEDICINE Ketteler, M., Block, G. A., Evenepoel, P., Fukagawa, M., Herzog, C. A., McCann, L., Moe, S. M., Shroff, R., Tonelli, M. A., Toussaint, N. D., Vervloet, M. G., Leonard, M. B. 2018; 168 (6): 422-+
Abstract

The Kidney Disease: Improving Global Outcomes (KDIGO) 2017 Clinical Practice Guideline Update for the Diagnosis, Evaluation, Prevention, and Treatment of Chronic Kidney Disease-Mineral and Bone Disorder (CKD-MBD) is a selective update of the prior CKD-MBD guideline published in 2009. The guideline update and the original publication are intended to assist practitioners caring for adults with CKD and those receiving long-term dialysis.Development of the guideline update followed an explicit process of evidence review and appraisal. The approach adopted by the Work Group and the evidence review team was based on systematic reviews of relevant trials, appraisal of the quality of the evidence, and rating of the strength of recommendations according to the GRADE (Grading of Recommendations Assessment, Development and Evaluation) approach. Searches of the English-language literature were conducted through September 2015 and were supplemented with targeted searches through February 2017. Final modification of the guidelines was informed by a public review process involving numerous stakeholders, including patients, subject matter experts, and industry and national organizations.The update process resulted in the revision of 15 recommendations. This synopsis focuses primarily on recommendations for diagnosis of and testing for CKD-MBD and treatment of CKD-MBD that emphasizes decreasing phosphate levels, maintaining calcium levels, and addressing elevated parathyroid hormone levels in adults with CKD stage G3a to G5 and those receiving dialysis. Key elements include basing treatment on trends in laboratory values rather than a single abnormal result and being cautious to avoid hypercalcemia when treating secondary hyperparathyroidism.

View details for DOI 10.7326/M17-2640

View details for Web of Science ID 000427827400017

View details for PubMedID 29459980
Increases in IGF-1 After Anti-TNF-alpha Therapy Are Associated With Bone and Muscle Accrual in Pediatric Crohn Disease JOURNAL OF CLINICAL ENDOCRINOLOGY & METABOLISM DeBoer, M. D., Lee, A. M., Herbert, K., Long, J., Thayu, M., Griffin, L. M., Baldassano, R. N., Denson, L. A., Zemel, B. S., Denburg, M. R., Herskovitz, R., Leonard, M. B. 2018; 103 (3): 936–45
Abstract

Low levels of insulinlike growth factor 1 (IGF-1) in pediatric and adolescent Crohn disease (CD) likely contribute to bone and muscle deficits.Assess changes in IGF-1 levels and associations with bone and muscle accrual following initiation of anti-tumor necrosis factor α (TNF-α) therapy in pediatric and adolescent CD.Participants (n = 75, age 5 to 21 years) with CD were enrolled in a prospective cohort study; 63 completed the 12-month visit.IGF-1 levels at baseline and 10 weeks, as well as dual-energy x-ray absorptiometry (DXA) and tibia peripheral quantitative computed tomography (pQCT) measures of bone and muscle at baseline and 12 months after initiation of anti-TNF-α therapy. Outcomes were expressed as sex-specific z scores.IGF-1 z scores increased from a median (interquartile range) of -1.0 (-1.58 to -0.17) to -0.36 (-1.04 to 0.36) over 10 weeks (P < 0.001). Lesser disease severity and systemic inflammation, as well as greater estradiol z scores (in girls), was significantly associated with greater IGF-1 z scores over time. DXA whole-body bone mineral content, leg lean mass, and total hip and femoral neck bone mineral density (BMD) z scores were low at baseline (P < 0.0001 vs reference data) and increased significantly (P < 0.001) over 12 months. Greater increases in IGF-1 z scores over 10 weeks predicted improvement in DXA bone and muscle outcomes and pQCT trabecular BMD and cortical area. Adjustment for changes in muscle mass markedly attenuated the associations between IGF-1 levels and bone outcomes.Short-term improvements in IGF-1 z scores predicted recovery of bone and muscle outcomes following initiation of anti-TNF-α therapy in pediatric CD. These data suggest that disease effects on growth hormone metabolism contribute to musculoskeletal deficits in CD.

View details for DOI 10.1210/jc.2017-01916

View details for Web of Science ID 000428808700015

View details for PubMedID 29329430
Longitudinal FGF23 Trajectories and Mortality in Patients with CKD JOURNAL OF THE AMERICAN SOCIETY OF NEPHROLOGY Isakova, T., Cai, X., Lee, J., Xie, D., Wang, X., Mehta, R., Allen, N. B., Scialla, J. J., Pencina, M. J., Anderson, A. H., Talierco, J., Chen, J., Fischer, M. J., Steigerwalt, S. P., Leonard, M. B., Hsu, C., de Boer, I. H., Kusek, J. W., Feldman, H. I., Wolf, M., CRIC Study Investigators 2018; 29 (2): 579–90
Abstract

Elevated fibroblast growth factor 23 (FGF23) levels, measured at a single time, are strongly associated with increased risk of mortality in patients with CKD. There are minimal data on serial FGF23 measurements in CKD. In a prospective case-cohort study of the Chronic Renal Insufficiency Cohort, we measured FGF23 at two to five annual time points (mean 4.0±1.2) in a randomly selected subcohort of 1135 participants, of whom 203 died, and all remaining 390 participants who died through mid-2013. Higher FGF23 was independently associated with increased risk of death in multivariable-adjusted analyses of time-varying FGF23 (hazard ratio per 1-SD increase in ln-transformed FGF23, 1.84; 95% CI, 1.67 to 2.03). Median FGF23 was stable over 5 years of follow-up, but its gradually right-skewed distribution suggested a subpopulation with markedly elevated FGF23. Trajectory analysis revealed three distinct trajectories: stable FGF23 in the majority of participants (slope of lnFGF23 per year =0.03, 95% CI, 0.02 to 0.04, n=724) and smaller subpopulations with slowly (slope=0.14, 95% CI, 0.12 to 0.16, n=486) or rapidly (slope=0.46, 95% CI, 0.38 to 0.54, n=99) rising levels. Compared with stable FGF23, participants with slowly rising FGF23 trajectories were at 4.49-fold higher risk of death (95% CI, 3.17 to 6.35) and individuals with rapidly rising FGF23 trajectories were at 15.23-fold higher risk of death (95% CI, 8.24 to 28.14) in fully adjusted analyses. Trajectory analyses that used four or three annual FGF23 measurements yielded qualitatively similar results. In conclusion, FGF23 levels are stable over time in the majority of patients with CKD, but serial measurements identify subpopulations with rising levels and exceptionally high risk of death.

View details for DOI 10.1681/ASN.2017070772

View details for Web of Science ID 000424142700027

View details for PubMedID 29167351

View details for PubMedCentralID PMC5791067
Effects of a Randomized Weight Loss Intervention Trial in Obese Adolescents on Tibia and Radius Bone Geometry and Volumetric Density JOURNAL OF BONE AND MINERAL RESEARCH Kelley, J. C., Stettler-Davis, N., Leonard, M. B., Hill, D., Wrotniak, B. H., Shults, J., Stallings, V. A., Berkowitz, R., Xanthopoulos, M. S., Prout-Parks, E., Klieger, S. B., Zemel, B. S. 2018; 33 (1): 42–53
Abstract

Obese adolescents have increased fracture risk, but effects of alterations in adiposity on bone accrual and strength in obese adolescents are not understood. We evaluated 12-month changes in trabecular and cortical volumetric bone mineral density (vBMD) and cortical geometry in obese adolescents undergoing a randomized weight management program, and investigated the effect of body composition changes on bone outcomes. Peripheral quantitative computed tomography (pQCT) of the radius and tibia, and whole-body dual-energy X-ray absorptiometry (DXA) scans were obtained at baseline, 6 months, and 12 months in 91 obese adolescents randomized to standard care versus behavioral intervention for weight loss. Longitudinal models assessed effects of body composition changes on bone outcomes, adjusted for age, bone length, and African-American ancestry, and stratified by sex. Secondary analyses included adjustment for physical activity, maturation, vitamin D, and inflammatory biomarkers. Baseline body mass index (BMI) was similar between intervention groups. Twelve-month change in BMI in the standard care group was 1.0 kg/m2 versus -0.4 kg/m2 in the behavioral intervention group (p < 0.01). Intervention groups were similar in bone outcomes, so they were combined for subsequent analyses. For the tibia, BMI change was not associated with change in vBMD or structure. Greater baseline lean body mass index (LBMI) associated with higher cortical vBMD in males, trabecular vBMD in females, and polar section modulus (pZ) and periosteal circumference (Peri-C) in both sexes. In females, change in LBMI positively associated with gains in pZ and Peri-C. Baseline visceral adipose tissue (VFAT) was inversely associated with pZ in males and cortical vBMD in females. Change in VFAT did not affect bone outcomes. For the radius, BMI and LBMI changes positively associated with pZ in males. Thus, in obese adolescents, weight loss intervention with modest changes in BMI was not detrimental to radius or tibia bone strength, and changes in lean, but not adiposity, measures were beneficial to bone development. © 2017 American Society for Bone and Mineral Research.

View details for DOI 10.1002/jbmr.3288

View details for Web of Science ID 000422723400008

View details for PubMedID 28884881
Changes in Hepcidin and Hemoglobin After Anti-TNF-alpha Therapy in Children and Adolescents With Crohn Disease JOURNAL OF PEDIATRIC GASTROENTEROLOGY AND NUTRITION Atkinson, M. A., Leonard, M. B., Herskovitz, R., Baldassano, R. N., Denburg, M. R. 2018; 66 (1): 90–94
Abstract

Anemia is the most common systemic complication of inflammatory bowel disease, is more common in affected children than in adults, and is mediated in large part by chronic inflammation. Inflammation increases levels of the iron-regulatory protein hepcidin, which have been elevated in adults with Crohn disease.We measured serum hepcidin-25 and hemoglobin (Hgb) in 40 children and adolescents with Crohn disease at baseline and 10 weeks after initiation of anti-tumor necrosis factor (TNF)-α therapy. Measures of disease activity, inflammatory markers, and cytokines were obtained in all subjects. Anemia was defined by World Health Organization criteria.At baseline hepcidin and C-reactive protein levels were correlated, and 95% of subjects were anemic. After anti-TNF-α therapy, median (interquartile range) hepcidin concentrations decreased significantly and the distribution narrowed (27.9 [16.2, 52.9] vs 23.2 [11.1, 37.7] ng/mL, P = 0.01). Mean (standard deviation) Hgb also increased significantly (10.6 ± 1.2 to 10.9 ± 1.1 g/dL, P = 0.02), and the increase was sustained at 12 months, although 90% of participants continued to meet anemia criteria at 10 weeks. Disease activity and markers of inflammation also decreased and albumin levels increased. In generalized estimating equation analyses, higher TNF-α, interleukin 6, erythrocyte sedimentation rate, and C-reactive protein were associated with higher hepcidin concentrations (P = 0.04, P = 0.03, P = 0.003, and P < 0.001, respectively), and increased levels of disease activity were associated with higher hepcidin.In children with Crohn disease, anti-TNF-α therapy is associated with decreased levels of hepcidin and increased Hgb 10 weeks after induction. Improvement in anemia may be a secondary benefit for children who receive this therapy.

View details for DOI 10.1097/MPG.0000000000001650

View details for Web of Science ID 000425389400029

View details for PubMedID 28604512

View details for PubMedCentralID PMC5723254
Bone Strength and Microarchitectural Deficits in Children with Cystinosis. Burghardt, A., Kent, K., Long, J., Whalen, J., Leonard, M. WILEY. 2017: S124
View details for Web of Science ID 000418869201178
Variability in measures of mineral metabolism in children on hemodialysis: impact on clinical decision-making PEDIATRIC NEPHROLOGY Kakajiwala, A., Jemielita, T. O., Copelovitch, L., Leonard, M. B., Furth, S. L., York, A., Benton, M., Hoofnagle, A. N., Windt, K., Merrigan, K., Lederman, A., Denburg, M. R. 2017; 32 (12): 2311–18
Abstract

Variability in measures of mineral metabolism has not been studied in pediatric end stage kidney disease. We sought to determine the intra-individual variability in measures of mineral metabolism in children on hemodialysis (HD) and its impact on clinical decision-making.We conducted a prospective single-center study of children (3.6-17.3 years old) on chronic HD. Serial twice weekly measures of serum calcium, phosphate and intact parathyroid hormone (PTH), as well as weekly measures of fibroblast growth factor 23 (FGF23) and vitamin D metabolites, were obtained over a 12-week period in 10 children. Samples (n = 226) were assayed in a single batch at the end of the study.The median intra-individual coefficient of variation (CV) calculated by 4-week blocks was 5.1-6.5% for calcium, 9.5-14.9% for phosphate and 32.7-33.4% for PTH. The median overall CV for FGF23 was 44.4%. Using the first value of each block as a reference, subsequent values would dictate a discrepant management decision 33-56%, 19-28%, and 30-33% of the time for calcium, phosphate, and PTH, respectively. Adjusting for sex and age, most of the variability in phosphate and PTH was attributable to within-participant variability. For calcium, 49% of the variability was attributable to day of blood collection (Monday vs. Friday). The median (range) of an individual participant's values within clinical target ranges was 55% (26-86%) for calcium, 58% (0-96%) for phosphate, and 21% (0-64%) for PTH.There is considerable intra-individual variability in measures of mineral metabolism that serve as surrogate markers for bone health in children on HD. Within a 4-week period, at least 20-30% of measures would dictate a discrepant decision from the referent measure of that month. These findings have important implications for clinical decision-making and underscore the need to base therapeutic decisions on trends rather than single measurements.

View details for DOI 10.1007/s00467-017-3730-4

View details for Web of Science ID 000413678800014

View details for PubMedID 28667458
Declining Rates of Hip Fracture in End-Stage Renal Disease: Analysis From the 2003-2011 Nationwide Inpatient Sample JOURNAL OF BONE AND MINERAL RESEARCH Kim, S., Liu, S., Long, J., Montez-Rath, M. E., Leonard, M. B., Chertow, G. M. 2017; 32 (11): 2297–2303
Abstract

The incidence of hip fracture in patients with end-stage renal disease (ESRD) is considerably higher than that in the general age- and sex-matched population. Although medical therapy for chronic kidney disease mineral bone disorder (CKD-MBD) has changed considerably over the last decade, rates of hip fracture in the entire ESRD population have not been well-characterized. Herein, we evaluated temporal trends in rates of hip fracture, in-hospital mortality, and costs of associated hospital stay in ESRD. We identified hospitalizations for hip fracture from 2003 to 2011 using the Nationwide Inpatient Sample, a representative national database inclusive of all ages and payers. We incorporated data from the United States Renal Data System and the US Census to calculate population-specific rates. Between 2003 and 2011, we identified 47,510 hip fractures in the ESRD population. The overall rate of hip fracture was 10.04/1000 person-years. The rate was 3.73/1000 person-years in patients aged less than 65 years, and 20.97/1000 person-years in patients aged 65 or older. Age- and sex-standardized rates decreased by 12.6% from 2003 (10.23/1000 person-years; 95% confidence interval [CI], 7.99/1000 to 12.47/1000) to 2011 (8.94/1000 person-years; 95% CI, 7.12/1000 to 10.75/1000). Hip fracture rates over time were virtually identical in patients aged less than 65 years; however, rates decreased by 15.3% among patients aged 65 years or older; rates declined more rapidly in older women compared with older men (p for interaction = 0.047). In-hospital mortality rate after hip fracture operation declined by 26.7% from 2003 (8.6%; 95% CI, 6.8 to 10.4) to 2011 (6.3%; 95% CI, 4.9 to 7.7). In ESRD, age- and sex-standardized hip fracture rates and associated in-hospital mortality have declined substantially over the last decade. © 2017 American Society for Bone and Mineral Research.

View details for DOI 10.1002/jbmr.3201

View details for Web of Science ID 000417766700017

View details for PubMedID 28639740

View details for PubMedCentralID PMC5685922
Acid Load and Phosphorus Homeostasis in CKD AMERICAN JOURNAL OF KIDNEY DISEASES Khairallah, P., Isakova, T., Asplin, J., Hamm, L., Dobre, M., Rahman, M., Sharma, K., Leonard, M., Miller, E., Jaar, B., Brecklin, C., Yang, W., Wang, X., Feldman, H., Wolf, M., Scialla, J. J., Chronic Renal Insufficiency Cohort 2017; 70 (4): 541–50
Abstract

The kidneys maintain acid-base homeostasis through excretion of acid as either ammonium or as titratable acids that primarily use phosphate as a buffer. In chronic kidney disease (CKD), ammoniagenesis is impaired, promoting metabolic acidosis. Metabolic acidosis stimulates phosphaturic hormones, parathyroid hormone (PTH) and fibroblast growth factor 23 (FGF-23) in vitro, possibly to increase urine titratable acid buffers, but this has not been confirmed in humans. We hypothesized that higher acid load and acidosis would associate with altered phosphorus homeostasis, including higher urinary phosphorus excretion and serum PTH and FGF-23.Cross-sectional.980 participants with CKD enrolled in the Chronic Renal Insufficiency Cohort (CRIC) Study.Net acid excretion as measured in 24-hour urine, potential renal acid load (PRAL) estimated from food frequency questionnaire responses, and serum bicarbonate concentration < 22 mEq/L.24-hour urine phosphorus and calcium excretion and serum phosphorus, FGF-23, and PTH concentrations.Using linear and log-linear regression adjusted for demographics, kidney function, comorbid conditions, body mass index, diuretic use, and 24-hour urine creatinine excretion, we found that 24-hour urine phosphorus excretion was higher at higher net acid excretion, higher PRAL, and lower serum bicarbonate concentration (each P<0.05). Serum phosphorus concentration was also higher with higher net acid excretion and lower serum bicarbonate concentration (each P=0.001). Only higher net acid excretion associated with higher 24-hour urine calcium excretion (P<0.001). Neither net acid excretion nor PRAL was associated with FGF-23 or PTH concentrations. PTH, but not FGF-23, concentration (P=0.2) was 26% (95% CI, 13%-40%) higher in participants with a serum bicarbonate concentration <22 versus ≥22 mEq/L (P<0.001). Primary results were similar if stratified by estimated glomerular filtration rate categories or adjusted for iothalamate glomerular filtration rate (n=359), total energy intake, dietary phosphorus, or urine urea nitrogen excretion, when available.Possible residual confounding by kidney function or nutrition; urine phosphorus excretion was included in calculation of the titratable acid component of net acid excretion.In CKD, higher acid load and acidosis associate independently with increased circulating phosphorus concentration and augmented phosphaturia, but not consistently with FGF-23 or PTH concentrations. This may be an adaptation that increases titratable acid excretion and thus helps maintain acid-base homeostasis in CKD. Understanding whether administration of base can lower phosphorus concentrations requires testing in interventional trials.

View details for DOI 10.1053/j.ajkd.2017.04.022

View details for Web of Science ID 000411189900015

View details for PubMedID 28645705

View details for PubMedCentralID PMC5804342
Muscle Deficits in Rheumatoid Arthritis Contribute to Inferior Cortical Bone Structure and Trabecular Bone Mineral Density. The Journal of rheumatology Baker, J. F., Long, J., Mostoufi-Moab, S., Denburg, M., Jorgenson, E., Sharma, P., Zemel, B. S., Taratuta, E., Ibrahim, S., Leonard, M. B. 2017
Abstract

OBJECTIVE: Rheumatoid arthritis (RA) is associated with muscle loss, osteoporosis, and fracture. We examined associations between skeletal muscle mass, strength, and quality and trabecular and cortical bone deficits in patients with RA and healthy controls.METHODS: Participants, ages 18-75 years, completed whole-body dual-energy x-ray absorptiometry and peripheral quantitative computed tomography (pQCT) of the tibia to quantify appendicular lean mass and fat mass indices (ALMI, FMI), muscle density at the lower leg, trabecular bone density, and cortical bone thickness. Age-, sex-, and race-specific Z scores were calculated based on distributions in controls. Associations between body composition and pQCT bone outcomes were assessed in patients with RA and controls. Linear regression analyses assessed differences in bone outcomes after considering differences in body mass index (BMI) and body composition.RESULTS: The sample consisted of 112 patients with RA (55 men) and 412 controls (194 men). Compared to controls, patients with RA had greater BMI Z score (p < 0.001), lower ALMI Z score after adjustment for FMI (p = 0.02), lower muscle strength Z score (p = 0.01), and lower muscle density Z score (p < 0.001). Among RA, ALMI Z scores were positively associated with trabecular density [beta: 0.29 (0.062-0.52); p = 0.01] and cortical thickness [beta: 0.33 (0.13-0.53; p = 0.002]. Associations were similar in controls. Bone outcomes were inferior in patients with RA after adjusting for BMI, but similar to controls when adjusting for body composition. Radiographic damage and higher adiponectin levels were independently associated with inferior bone outcomes.CONCLUSION: Patients with RA exhibit deficits in cortical bone structure and trabecular density at the tibia and a preserved functional muscle-bone unit. A loss of mechanical loading may contribute to bone deficits.

View details for DOI 10.3899/jrheum.170513

View details for PubMedID 28916544
Assessment of muscle mass relative to fat mass and associations with physical functioning in rheumatoid arthritis. Rheumatology Baker, J. F., Giles, J. T., Weber, D., Leonard, M. B., Zemel, B. S., Long, J., Ibrahim, S., Katz, P. P. 2017; 56 (6): 981-988
Abstract

To determine whether a novel measure of appendicular lean mass relative to fat mass is associated with physical functioning in RA.In a cross-sectional design, three independent RA cohorts were retrospectively analysed. Whole-body DXA measures of appendicular lean mass index (ALMI, kg/m 2 ) and fat mass index (FMI, kg/m 2 ) were converted to age, sex and race-specific Z-scores using published National Health and Nutrition Examination Survey reference ranges. Adiposity-adjusted ALMI Z-scores (ALMI FMI ) were determined using a published method to adjust for normal associations between ALMI and FMI Z-scores. Associations between ALMI Z-scores, ALMI FMI Z-scores and physical functioning were assessed after adjusting for age, sex and study. Functional outcomes assessed included the HAQ, Valued Life Activities assessment and Short Physical Performance Battery. Low lean for age was defined as a Z-score of -1 or less.Our sample consisted of 442 patients with RA. The combined cohort had a mean ALMI Z-score of - 0.51 (1.08) and a mean ALMI FMI Z-score of - 0.58 (1.53), suggesting muscle mass deficits compared with a nationally representative sample. Greater ALMI FMI Z-scores demonstrated stronger associations with better functional outcomes compared with ALMI Z-scores. Associations were not attenuated with adjustment for systemic inflammation or pain. The FMI Z-score was independently associated with physical functioning, with a stronger association seen among patients with greater FMI Z-score. Adiposity-adjusted definitions of low lean mass more clearly identified those with functional impairment.Estimates of appendicular lean mass that are adjusted for adiposity demonstrate stronger positive associations with functional outcomes compared with unadjusted estimates.

View details for DOI 10.1093/rheumatology/kex020

View details for PubMedID 28340012
Assessment of Sex Differences in Fracture Risk Among Patients With Anorexia Nervosa: A Population-Based Cohort Study Using The Health Improvement Network JOURNAL OF BONE AND MINERAL RESEARCH Nagata, J. M., Golden, N. H., Leonard, M. B., Copelovitch, L., Denburg, M. R. 2017; 32 (5): 1082-1089
View details for DOI 10.1002/jbmr.3068

View details for Web of Science ID 000400590900021
Assessment of sex differences in bone deficits among adolescents with anorexia nervosa INTERNATIONAL JOURNAL OF EATING DISORDERS Nagata, J. M., Golden, N. H., Peebles, R., Long, J., Leonard, M. B., Chang, A. O., Carlson, J. L. 2017; 50 (4): 352-358
Abstract

The objective of this study was to compare sex differences in bone deficits among adolescents with anorexia nervosa (AN) and to identify other correlates of bone health.Electronic medical records of all patients 9-20 years of age with a DSM-5 diagnosis of AN who were evaluated by the eating disorders program at Stanford with dual-energy X-ray absorptiometry (DXA) between March 1997 and February 2011 were retrospectively reviewed. Whole body bone mineral content Z-scores and bone mineral density (BMD) Z-scores at multiple sites were recorded using the Bone Mineral Density in Childhood Study (BMDCS) reference data.A total of 25 males and 253 females with AN were included, with median age 15 years (interquartile range [IQR] 14-17) and median duration of illness 9 months (IQR 5-13). Using linear regression analyses, no significant sex differences in bone deficits were found at the lumbar spine, total hip, femoral neck, or whole body when controlling for age, %mBMI, and duration of illness. Lower %mBMI was significantly associated with bone deficits at all sites in adjusted models.This is the first study to evaluate sex differences in bone health among adolescents with AN, using novel DSM-5 criteria for AN and robust BMDCS reference data. We find no significant sex differences in bone deficits among adolescents with AN except for a higher proportion of females with femoral neck BMD Z-scores <-1. Degree of malnutrition was correlated with bone deficits at all sites. © 2016 Wiley Periodicals, Inc. (Int J Eat Disord 2016).

View details for DOI 10.1002/eat.22626

View details for Web of Science ID 000398841500004
Commercially available lifestyle modification program: randomized controlled trial addressing heart and bone health in BRCA1/2+breast cancer survivors after risk-reducing salpingo-oophorectomy JOURNAL OF CANCER SURVIVORSHIP Sturgeon, K. M., Dean, L. T., Heroux, M., Kane, J., Bauer, T., Palmer, E., Long, J., Lynch, S., Jacobs, L., Sarwer, D. B., Leonard, M. B., Schmitz, K. 2017; 11 (2): 246-255
View details for DOI 10.1007/s11764-016-0582-z

View details for Web of Science ID 000398471600008
Body composition estimation using skinfolds in children with and without health conditions affecting growth and body composition. Annals of human biology Wendel, D., Weber, D., Leonard, M. B., Magge, S. N., Kelly, A., Stallings, V. A., Pipan, M., Stettler, N., Zemel, B. S. 2017; 44 (2): 108-120
Abstract

Body composition prediction equations using skinfolds are useful alternatives to advanced techniques, but their utility across diverse paediatric populations is unknown.To evaluate published and new prediction equations across diverse samples of children with health conditions affecting growth and body composition.Anthropometric and dual-energy X-ray absorptiometry (DXA) body composition measures were obtained in children with Down syndrome (n = 59), Crohn disease (n = 128), steroid-sensitive nephrotic syndrome (n = 67) and a healthy reference group (n = 835). Published body composition equations were evaluated. New equations were developed for ages 3-21 years using the healthy reference sample and validated in other groups and national survey data.Fat mass (FM), fat-free mass (FFM) and percentage body fat (%BF) from published equations were highly correlated with DXA-derived measures (r = 0.71-0.98), but with poor agreement (mean difference = 2.4 kg, -1.9 kg and 6.3% for FM, FFM and %BF). New equations produced similar correlations (r = 0.85-1.0) with improved agreement for the reference group (0.2 kg, 0.4 kg and 0.0% for FM, FFM and %BF, respectively) and in sub-groups.New body composition prediction equations show excellent agreement with DXA and improve body composition estimation in healthy children and those with selected conditions affecting growth.

View details for DOI 10.3109/03014460.2016.1168867

View details for PubMedID 27121656
Assessment of Sex Differences in Body Composition Among Adolescents With Anorexia Nervosa. journal of adolescent health Nagata, J. M., Golden, N. H., Peebles, R., Long, J., Murray, S. B., Leonard, M. B., Carlson, J. L. 2017
Abstract

To compare deficits in fat mass (FM) and lean body mass (LM) among male and female adolescents with anorexia nervosa (AN) and to identify other covariates associated with body composition.We retrospectively reviewed electronic medical records of all subjects aged 9-20 years with a Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition diagnosis of AN and dual-energy x-ray absorptiometry scans after initial evaluation at Stanford between March 1997 and February 2011. From the dual-energy x-ray absorptiometry scans, LM and FM results were converted to age-, height-, sex-, and race-specific Z-scores for age using the National Health and Nutrition Examination Survey reference data.A total of 16 boys and 119 girls with AN met eligibility criteria. The FM Z-score in girls with AN (-3.24 ± 1.50) was significantly lower than that in boys with AN (-2.41 ± .96) in unadjusted models (p = .007). LM was reduced in both girls and boys with AN, but there was no significant sex difference in LM Z-scores. In multivariate models, lower percentage median body mass index was significantly associated with lower FM Z-scores (β = .08, p < .0001) and lower LM Z-score (β = .03, p = .0002), whereas lower whole body bone mineral content Z-score was significantly associated with lower LM Z-score (β = .21, p = .0006).FM deficits in girls were significantly greater than those in boys with AN in unadjusted models; however, the degree of malnutrition appeared to be the primary factor accounting for this difference. There were no significant sex differences in FM or LM in adjusted models.

View details for DOI 10.1016/j.jadohealth.2016.11.005

View details for PubMedID 28087266
Effect of high-dose cholecalciferol (vitamin D-3) on bone and body composition in children and young adults with HIV infection: a randomized, double-blind, placebo-controlled trial OSTEOPOROSIS INTERNATIONAL Rovner, A. J., Stallings, V. A., Rutstein, R., Schall, J. I., Leonard, M. B., Zemel, B. S. 2017; 28 (1): 201-209
View details for DOI 10.1007/s00198-016-3826-x

View details for Web of Science ID 000391390100020
Risk of Urolithiasis in Anorexia Nervosa: A Population-Based Cohort Study Using the Health Improvement Network. European eating disorders review : the journal of the Eating Disorders Association Denburg, M. R., Leonard, M. B., Jemielita, T. O., Golden, N. H., Tasian, G., Copelovitch, L. 2017
Abstract

This population-based retrospective cohort study sought to determine if anorexia nervosa (AN) is associated with a higher risk of urolithiasis. Nine thousand three hundred two females with AN were compared to 92 959 randomly selected age-matched and practice-matched females. Cox regression was used to estimate the hazard ratio (HR) for urolithiasis and evaluate effect modification by age. Twenty-three participants with AN (0.25%) developed urolithiasis compared with 154 unexposed participants (0.17%) over a median of 4 years of observation. The risk of urolithiasis varied significantly with age (interaction p = 0.02). AN was associated with a more than threefold higher risk of urolithiasis in females ≤25 years of age (HR 3.49, 95% CI: 1.56-7.81; p = 0.002), but not in females over 25 years (HR 1.18, 95% CI: 0.69-2.02; p = 0.54). The distribution of diagnosis codes for urolithiasis differed between groups (p = 0.04), with a higher proportion of codes for uric acid urolithiasis in the AN (16.2%) versus unexposed group (5.0%). Copyright © 2017 John Wiley & Sons, Ltd and Eating Disorders Association.

View details for DOI 10.1002/erv.2526

View details for PubMedID 28660717
) on bone and body composition in children and young adults with HIV infection: a randomized, double-blind, placebo-controlled trial. Osteoporosis international Rovner, A. J., Stallings, V. A., Rutstein, R., Schall, J. I., Leonard, M. B., Zemel, B. S. 2017; 28 (1): 201-209
Abstract

It is unknown whether vitamin D supplementation positively impacts body composition and bone outcomes in children and young adults with HIV. This RCT found that despite increasing 25(OH)D concentrations, high dose vitamin D3 supplementation did not impact bone or body composition in children and young adults with HIV infection.The objective of this paper was to determine the impact of high-dose daily cholecalciferol (vitamin D3) supplementation on body composition and bone density, structure, and strength in children and young adults with perinatally acquired (PHIV) or behaviorally acquired (BHIV) HIV infection.Participants were randomized to receive vitamin D3 supplementation (7000 IU/day) or placebo for 12 months. Serum 25-hydroxyvitamin D [25(OH)D] concentrations, dual energy X-ray absorptiometry (DXA) of the whole body and lumbar spine, and peripheral quantitative computed tomography (pQCT) of tibia sites were acquired at 0, 6, and 12 months. DXA and pQCT outcomes were expressed as sex- and population-ancestry specific Z-scores relative to age and adjusted for height or tibia length, as appropriate.Fifty-eight participants (5.0 to 24.9 years) received vitamin D3 supplements (n = 30) or placebo (n = 28). At enrollment, groups were similar in age, sex, population ancestry, growth status, serum 25(OH)D concentrations, body composition, and size-adjusted bone measures. Median 25(OH)D concentrations were similar (17.3 ng/mL in the vitamin D3 supplementation group vs 15.6 ng/mL in the placebo group), and both groups had mild bone deficits. At 12 months, 25(OH)D rose significantly in the vitamin D supplementation group but not in the placebo group (26.4 vs 14.8 ng/mL, respectively, p < 0.008). After adjusting for population ancestry, sex, antiretroviral therapy use, and season, there were no significant treatment group differences in bone or body composition outcomes.Despite increasing 25(OH)D concentrations, 12 months of high-dose vitamin D3 supplementation did not impact bone or body composition in children and young adults with HIV infection.

View details for DOI 10.1007/s00198-016-3826-x

View details for PubMedID 27837268
Assessment of Sex Differences in Fracture Risk Among Patients With Anorexia Nervosa: A Population-Based Cohort Study Using The Health Improvement Network. Journal of bone and mineral research Nagata, J. M., Golden, N. H., Leonard, M. B., Copelovitch, L., Denburg, M. R. 2016
Abstract

Though previous studies have demonstrated an increased fracture risk in females with anorexia nervosa (AN), fracture risk in males is not well characterized. The objective of this study was to examine sex differences in fracture risk and site-specific fracture incidence in AN. We performed a population-based retrospective cohort study using The Health Improvement Network (THIN; a large database of anonymized electronic medical records collected at primary care clinics throughout the United Kingdom). The median calendar year for the start of the observation period was 2004-2005. We identified 9239 females and 556 males <60 years of age with AN, and 97,889 randomly selected sex-, age-, and practice-matched participants without eating disorders (92,329 females and 5560 males). Multivariable Cox regression was used to estimate the hazard ratio (HR) for incident fracture. Median age at start of observation was 29.8 years in females and 30.2 years in males. The HR for fracture associated with AN differed by sex and age (interaction p = 0.002). Females with AN had an increased fracture risk at all ages (HR, 1.59; 95% confidence interval [CI], 1.45 to 1.75). AN was associated with a higher risk of fracture among males >40 years of age (HR, 2.54; 95% CI, 1.32 to 4.90; p = 0.005) but not among males ≤40 years. Females with AN had a higher risk of fracture at nearly all anatomic sites. The greatest excess fracture risk was noted at the hip/femur (HR, 5.59; 95% CI, 3.44 to 9.09) and pelvis (HR, 4.54; 95% CI, 2.42 to 8.50) in females and at the vertebrae (HR, 7.25; 95% CI, 1.21 to 43.45) for males with AN. AN was associated with higher incident fracture risk in females across all age groups and in males >40 years old. Sites of highest fracture risk include the hip/femur and pelvis in females and vertebrae in males with AN. © 2016 American Society for Bone and Mineral Research.

View details for DOI 10.1002/jbmr.3068

View details for PubMedID 28019700
Skeletal outcomes by peripheral quantitative computed tomography and dual-energy X-ray absorptiometry in adolescent girls with anorexia nervosa OSTEOPOROSIS INTERNATIONAL DiVasta, A. D., Feldman, H. A., O'Donnell, J. M., Long, J., Leonard, M. B., Gordon, C. M. 2016; 27 (12): 3549-3558
Abstract

We conducted the first comparison of dual-energy X-ray absorptiometry (DXA) and peripheral quantitative computed tomography (pQCT) outcomes in adolescent girls with anorexia nervosa. We observed deficits in bone density by both tools. pQCT assessments were associated with many of the same clinical parameters as have been previously established for DXA.Adolescents with anorexia nervosa (AN) commonly exhibit bone loss, but effects on bone geometry are less clear. We compared measures obtained by DXA and pQCT in girls with AN.Seventy females (age 15.5 ± 1.9 years ) with AN and 132 normal-weighted controls underwent tibial measures by pQCT including trabecular volumetric bone mineral density (vBMD) at the 3 % site, cortical vBMD and dimensions at the 38 % site, and muscle cross-sectional area (CSA) at the 66 % site. Participants with AN also underwent standard DXA measures. Independent t tests compared the pQCT results, while Pearson coefficient assessed correlations among DXA and pQCT measures.Trabecular vBMD Z-scores were lower in AN compared to controls (AN -0.31 ± 1.42 vs +0.11 ± 1.01, p = 0.01) and cortical vBMD Z-scores were higher (AN +0.18 ± 0.92 vs -0.50 ± 0.88, p < 0.001). Trabecular vBMD and cortical CSA Z-scores positively correlated with DXA BMD Z-scores (r range 0.57-0.82, p < 0.001). Markers of nutritional status positively correlated with Z-scores for trabecular vBMD, cortical CSA, section modulus, and muscle CSA (p < 0.04 for all).This study is the first to compare DXA and pQCT measurements in adolescent girls with AN. We observed deficits in BMD by both DXA and pQCT. pQCT assessments correlated well with DXA bone and body composition measures and were associated with many of the same clinical parameters and disease severity markers as have been previously established for DXA. The differences in cortical vBMD merit further study.

View details for DOI 10.1007/s00198-016-3685-5

View details for Web of Science ID 000388953700016

View details for PubMedID 27392467
Development of Novel Methods to Define Deficits in Appendicular Lean Mass Relative to Fat Mass PLOS ONE Weber, D., Long, J., Leonard, M. B., Zemel, B., Baker, J. F. 2016; 11 (10)
Abstract

Recent studies suggest that adjustment of measures of lean mass for adiposity improves associations with physical function. Our objective was to develop and test a method to adjust appendicular lean mass for adiposity.Whole-body DXA data in 14,850 adults in the National Health and Nutrition Examination Survey were used to generate sex-, and race-specific standard deviation scores (Z-Scores relative to age and T-scores relative to 25 year-olds) for appendicular lean mass index (ALMI, kg/m2) and fat mass index (FMI, kg/m2). Correlations between ALMI and FMI Z- and T-Scores were assessed within demographic categories. Fat-adjusted ALMI (ALMIFMI) scores were determined using residual methods. Sarcopenia was defined as a T-Score <-2.0 and low lean for age as a Z-Score <-1.0. Correlations with physical function were assessed in an at-risk population.Positive associations between ALMI and FMI Z- and T-Scores were significant (R >0.50; p<0.001) within all demographic categories. The impact of a unit greater FMI Z-score on ALMI Z-score was less in the elderly, men, white subjects, and among individuals with lower FMI (all tests for interaction p<0.001). There was fair agreement between ALMI and ALMIFMI estimates of sarcopenia and low lean for age [Kappa: 0.46, 0.52, respectively (p<0.0001)]. Elderly subjects were likely to be re-classified as sarcopenic while young subjects were likely to be re-classified as normal using ALMIFMI. ALMIFMI T-scores resulted in approximately twice the number of subjects defined as sarcopenic, compared with ALMI T-Scores. (1299 v. 534). Among rheumatoid arthritis patients, ALMIFMI Z-scores correlated with physical function (Health Assessment Questionnaire: rho = -0.22, p = 0.04; Short Physical Performance Battery: rho = 0.27, p = 0.01); however, the ALMI Z-Score did not.Adjustment of ALMI for the confounding association with FMI impacts the definition of lean mass deficits. These methods provide a practical tool for investigators and clinicians based on population-based reference data.

View details for DOI 10.1371/journal.pone.0164385

View details for Web of Science ID 000385504100053

View details for PubMedID 27723820

View details for PubMedCentralID PMC5056731
Hip Fracture in Patients With Non-Dialysis-Requiring Chronic Kidney Disease. Journal of bone and mineral research Kim, S. M., Long, J., Montez-Rath, M., Leonard, M., Chertow, G. M. 2016; 31 (10): 1803-1809
Abstract

Patients with end-stage renal disease (ESRD) are at a high risk for hip fracture. Little is known about the risk for, and consequences of, hip fracture among patients with non-dialysis-requiring chronic kidney disease (CKD). We examined the incidence of hip fracture, in-hospital mortality, length of stay, and costs among patients with ESRD, non-dialysis-requiring CKD, and normal or near normal kidney function. Using the Healthcare Cost and Utilization Project's Nationwide Inpatient Sample, a nationally representative database, we identified hospitalizations for hip fracture in 2010. We incorporated data from the United States Renal Data System (USRDS) and the US census to calculate population-specific rates. Age-standardized incidence of hip fracture was highest among patients with ESRD (3.89/1000 person-years), followed by non-dialysis-requiring CKD (1.81/1000 persons) and patients with normal or near normal kidney function (1.18/1000 persons). In-hospital mo rtality (odds ratio [OR] = 1.69, 95% confidence interval [CI] 1.46 to 1.96), lengths of stay (median [10th, 90th percentiles] 5 [3 to 11] versus 5 [3 to 10] days) and costs (median $14,807 versus $13,314) were significantly higher in patients with non-dialysis-requiring CKD relative to patients with normal or near normal kidney function. In summary, non-dialysis-requiring CKD is associated with higher age-standardized rates of hip fracture and post-hip fracture mortality and higher resource utilization. © 2016 American Society for Bone and Mineral Research.

View details for DOI 10.1002/jbmr.2862

View details for PubMedID 27145189
Children with lower respiratory tract infections and serum 25-hydroxyvitamin D-3 levels: A case-control study PEDIATRIC PULMONOLOGY Velarde Lopez, A. A., Gerber, J. S., Leonard, M. B., Xie, D., Schinnar, R., Strom, B. L. 2016; 51 (10): 1080-1087
Abstract

Pneumonia is the leading cause of death in children under age of 5 years worldwide. The role of vitamin D in respiratory infections including pneumonia is unclear; therefore, we aimed to determine if children with lower respiratory tract infections had low serum 25-hydroxyvitamin D3 .We performed a case-control study of children ages 3-60 months from the Guatemala City metropolitan area, hospitalized with community-acquired pneumonia between September and December 2012. Controls were selected from the well-baby/care immunization clinics serving the population from which cases emerged. We analyzed serum 25-hydroxyvitamin D3 levels and conducted parental interviews to assess subject age, sex, race, feeding type, vitamin D supplementation, frequency of sun exposure, and maternal education. Height and weight were ascertained from medical records. Complete information was available for 70 (83%) of 84 eligible cases and 68 (60%) of 113 eligible controls.The median (IQR) serum 25-hydroxyvitamin D3 concentration for cases was 23.2 ng/ml (14.4-29.9) compared to 27.5 ng/ml (21.4-32.3) in controls (P = 0.006). Multiple regression analysis using an a priori cut-point for vitamin D of <20 ng/ml showed that children with lower respiratory tract infections were more likely to have low 25-hydroxyvitamin D3 levels than controls (adjusted odds ratio 2.4, 95% confidence interval 1.1-5.2, P = 0.02).Children with lower respiratory tract infections in Guatemala had low 25-hydroxyvitamin D3 levels. Pediatr Pulmonol. 2016;51:1080-1087. © 2016 Wiley Periodicals, Inc.

View details for DOI 10.1002/ppul.23439

View details for Web of Science ID 000384681100012

View details for PubMedID 27133156
Rates and Outcomes of Parathyroidectomy for Secondary Hyperparathyroidism in the United States CLINICAL JOURNAL OF THE AMERICAN SOCIETY OF NEPHROLOGY Kim, S. M., Long, J., Montez-Rath, M. E., Leonard, M. B., Norton, J. A., Chertow, G. M. 2016; 11 (7): 1260-1267
Abstract

Secondary hyperparathyroidism is common among patients with ESRD. Although medical therapy for secondary hyperparathyroidism has changed dramatically over the last decade, rates of parathyroidectomy for secondary hyperparathyroidism across the United States population are unknown. We examined temporal trends in rates of parathyroidectomy, in-hospital mortality, length of hospital stay, and costs of hospitalization.Using the Healthcare Cost and Utilization Project's Nationwide Inpatient Sample, a representative national database on hospital stay regardless of age and payer in the United States, we identified parathyroidectomies for secondary hyperparathyroidism from 2002 to 2011. Data from the US Renal Data System reports were used to calculate the rate of parathyroidectomy.We identified 32,971 parathyroidectomies for secondary hyperparathyroidism between 2002 and 2011. The overall rate of parathyroidectomy was approximately 5.4/1000 patients (95% confidence interval [95% CI], 5.0/1000 to 6.0/1000). The rate decreased from 2003 (7.9/1000 patients; 95% CI, 6.2/1000 to 9.6/1000), reached a nadir in 2005 (3.3/1000 patients; 95% CI, 2.6/1000 to 4.0/1000), increased again through 2006 (5.4/1000 patients; 95% CI, 4.4/1000 to 6.4/1000), and remained stable since that time. Rates of in-hospital mortality decreased from 1.7% (95% CI, 0.8% to 2.6%) in 2002 to 0.8% (95% CI, 0.1% to 1.6%) in 2011 (P for trend <0.001). In-hospital mortality rates were significantly higher in patients with heart failure (odds ratio [OR], 4.23; 95% CI, 2.59 to 6.91) and peripheral vascular disease (OR, 4.59; 95% CI, 2.75 to 7.65) and lower among patients with prior kidney transplantation (OR, 0.20; 95% CI, 0.06 to 0.65).Despite the use of multiple medical therapies, rates of parathyroidectomy of secondary hyperparathyroidism have not declined in recent years.

View details for DOI 10.2215/CJN.10370915

View details for Web of Science ID 000379195500019

View details for PubMedID 27269300

View details for PubMedCentralID PMC4934842
Effect of Low-Magnitude Mechanical Stimuli on Bone Density and Structure in Pediatric Crohn's Disease: A Randomized Placebo-Controlled Trial JOURNAL OF BONE AND MINERAL RESEARCH Leonard, M. B., Shults, J., Long, J., Baldassano, R. N., Brown, J. K., Hommel, K., Zemel, B. S., Mahboubi, S., Whitehead, K. H., Herskovitz, R., Lee, D., Rausch, J., Rubin, C. T. 2016; 31 (6): 1177-1188
Abstract

Pediatric Crohn's Disease (CD) is associated with low trabecular bone mineral density (BMD), cortical area, and muscle mass. Low-magnitude mechanical stimulation (LMMS) may be anabolic. We conducted a 12-month randomized double-blind placebo-controlled trial of 10 minutes daily exposure to LMMS (30 Hz frequency, 0.3 g peak-to-peak acceleration). The primary outcomes were tibia trabecular BMD and cortical area by peripheral quantitative CT (pQCT) and vertebral trabecular BMD by QCT; additional outcomes included dual-energy X-ray absorptiometry (DXA) whole body, hip and spine BMD, and leg lean mass. Results were expressed as sex-specific Z-scores relative to age. CD participants, ages 8 to 21 years with tibia trabecular BMD <25th percentile for age, were eligible and received daily cholecalciferol (800 IU) and calcium (1000 mg). In total, 138 enrolled (48% male), and 121 (61 active, 60 placebo) completed the 12-month trial. Median adherence measured with an electronic monitor was 79% and did not differ between arms. By intention-to-treat analysis, LMMS had no significant effect on pQCT or DXA outcomes. The mean change in spine QCT trabecular BMD Z-score was +0.22 in the active arm and -0.02 in the placebo arm (difference in change 0.24 [95% CI 0.04, 0.44]; p = 0.02). Among those with >50% adherence, the effect was 0.38 (95% CI 0.17, 0.58, p < 0.0005). Within the active arm, each 10% greater adherence was associated with a 0.06 (95% CI 0.01, 1.17, p = 0.03) greater increase in spine QCT BMD Z-score. Treatment response did not vary according to baseline body mass index (BMI) Z-score, pubertal status, CD severity, or concurrent glucocorticoid or biologic medications. In all participants combined, height, pQCT trabecular BMD, and cortical area and DXA outcomes improved significantly. In conclusion, LMMS was associated with increases in vertebral trabecular BMD by QCT; however, no effects were observed at DXA or pQCT sites. © 2016 American Society for Bone and Mineral Research.

View details for DOI 10.1002/jbmr.2799

View details for Web of Science ID 000377269200008

View details for PubMedCentralID PMC4891301
Effect of Low-Magnitude Mechanical Stimuli on Bone Density and Structure in Pediatric Crohn's Disease: A Randomized Placebo-Controlled Trial. Journal of bone and mineral research Leonard, M. B., Shults, J., Long, J., Baldassano, R. N., Brown, J. K., Hommel, K., Zemel, B. S., Mahboubi, S., Howard Whitehead, K., Herskovitz, R., Lee, D., Rausch, J., Rubin, C. T. 2016; 31 (6): 1177-1188
Abstract

Pediatric Crohn's Disease (CD) is associated with low trabecular bone mineral density (BMD), cortical area, and muscle mass. Low-magnitude mechanical stimulation (LMMS) may be anabolic. We conducted a 12-month randomized double-blind placebo-controlled trial of 10 minutes daily exposure to LMMS (30 Hz frequency, 0.3 g peak-to-peak acceleration). The primary outcomes were tibia trabecular BMD and cortical area by peripheral quantitative CT (pQCT) and vertebral trabecular BMD by QCT; additional outcomes included dual-energy X-ray absorptiometry (DXA) whole body, hip and spine BMD, and leg lean mass. Results were expressed as sex-specific Z-scores relative to age. CD participants, ages 8 to 21 years with tibia trabecular BMD <25th percentile for age, were eligible and received daily cholecalciferol (800 IU) and calcium (1000 mg). In total, 138 enrolled (48% male), and 121 (61 active, 60 placebo) completed the 12-month trial. Median adherence measured with an electronic monitor was 79% and did not differ between arms. By intention-to-treat analysis, LMMS had no significant effect on pQCT or DXA outcomes. The mean change in spine QCT trabecular BMD Z-score was +0.22 in the active arm and -0.02 in the placebo arm (difference in change 0.24 [95% CI 0.04, 0.44]; p = 0.02). Among those with >50% adherence, the effect was 0.38 (95% CI 0.17, 0.58, p < 0.0005). Within the active arm, each 10% greater adherence was associated with a 0.06 (95% CI 0.01, 1.17, p = 0.03) greater increase in spine QCT BMD Z-score. Treatment response did not vary according to baseline body mass index (BMI) Z-score, pubertal status, CD severity, or concurrent glucocorticoid or biologic medications. In all participants combined, height, pQCT trabecular BMD, and cortical area and DXA outcomes improved significantly. In conclusion, LMMS was associated with increases in vertebral trabecular BMD by QCT; however, no effects were observed at DXA or pQCT sites. © 2016 American Society for Bone and Mineral Research.

View details for DOI 10.1002/jbmr.2799

View details for PubMedID 26821779

View details for PubMedCentralID PMC4891301
Comparison of Two ELISA Methods and Mass Spectrometry for Measurement of Vitamin D-Binding Protein: Implications for the Assessment of Bioavailable Vitamin D Concentrations Across Genotypes JOURNAL OF BONE AND MINERAL RESEARCH Denburg, M. R., Hoofnagle, A. N., Sayed, S., Gupta, J., de Boer, I. H., Appel, L. J., Durazo-Arvizu, R., Whitehead, K., Feldman, H. I., Leonard, M. B. 2016; 31 (6): 1128-1136
Abstract

Studies using vitamin D-binding protein (DBP) concentrations to estimate free and bioavailable vitamin D have increased dramatically in recent years. Combinations of two single-nucleotide polymorphisms (SNPs) produce three major DBP isoforms (Gc1f, Gc1s, and Gc2). A recent study showed that DBP concentrations quantified by liquid chromatography-tandem mass spectrometry (LC-MS/MS) did not differ by race, whereas a widely used monoclonal enzyme-linked immunosorbent assay (ELISA) quantified DBP differentially by isoform, yielding significantly lower DBP concentrations in black versus white individuals. We compared measurements of serum DBP using a monoclonal ELISA, a polyclonal ELISA, and LC-MS/MS in 125 participants in the Chronic Renal Insufficiency Cohort (CRIC). Serum free and bioavailable 25OHD were calculated based on DBP concentrations from these three assays in homozygous participants, and race differences were compared. We confirmed that the monoclonal ELISA quantifies DBP differentially by isoform and showed that the polyclonal ELISA is not subject to this bias. Whereas ≤9% of the variability in DBP concentrations quantified using either LC-MS/MS or the polyclonal ELISA was explained by genotype, 85% of the variability in the monoclonal ELISA-based measures was explained by genotype. DBP concentrations measured by the monoclonal ELISA were disproportionately lower than LC-MS/MS-based results for Gc1f homozygotes (median difference -67%; interquartile range [IQR] -71%, -64%), 95% of whom were black. In contrast, the polyclonal ELISA yielded consistently and similarly higher measurements of DBP than LC-MS/MS, irrespective of genotype, with a median percent difference of +50% (IQR +33%, +65%). Contrary to findings using the monoclonal ELISA, DBP concentrations did not differ by race, and free and bioavailable 25OHD were significantly lower in black versus white participants based on both the polyclonal ELISA and LC-MS/MS, consistent with their lower total 25OHD. Future studies of DBP and free or bioavailable vitamin D metabolites should employ DBP assays that are not biased by DBP genotype. © 2016 American Society for Bone and Mineral Research.

View details for DOI 10.1002/jbmr.2829

View details for Web of Science ID 000377269200003

View details for PubMedID 27250744

View details for PubMedCentralID PMC4945118
Serum Infliximab, Antidrug Antibodies, and Tumor Necrosis Factor Predict Sustained Response in Pediatric Crohn's Disease INFLAMMATORY BOWEL DISEASES Stein, R., Lee, D., Leonard, M. B., Thayu, M., Denson, L. A., Chuang, E., Herskovitz, R., Kerbowski, T., Baldassano, R. N. 2016; 22 (6): 1370-1377
Abstract

Serum infliximab (s-IFX) levels, antibodies to IFX (ATI), and inflammatory markers are important in predicting clinical outcomes in adults, but their roles in pediatric Crohn's disease (CD) require further study. The primary aim of this study was to determine the association between serologic parameters during induction and ongoing IFX therapy at 12 months in pediatric CD.S-IFX, ATI, serum tumor necrosis factor alpha (s-TNF-α), and C-reactive protein were measured at IFX initiation, 10 weeks, 6 months, and 12 months in a prospective cohort study of children with CD at a single tertiary care center.At 12 months, 60 of 77 participants (78%) remained on IFX. Participants who completed 12 months of IFX had higher 10-week median s-IFX levels (20.40 μg/mL; interquartile range [IQR], 11.20-35.00] versus 8.70 μg/mL; IQR 0.90-16.90; P = 0.01), a greater proportion with undetectable 10-week ATI (P = 0.008), and a greater median change in s-TNF-α between baseline and week 10 (-5.96 pg/mL; IQR, -8.73 to -4.17 versus -1.76 pg/mL; IQR, -5.60 to 0.30; P = 0.006). Receiver operating characteristic analysis to predict ongoing IFX at 12 months showed area under the curve (95% confidence interval) for 10-week s-IFX and change in s-TNF-α from baseline to 10 weeks to be 0.71 (0.54-0.88) and 0.74 (0.58-0.91), respectively. C-reactive protein was not associated with ongoing therapy.ATI, s-IFX, and s-TNF-α during IFX induction are associated with 12-month clinical outcomes in pediatric CD. Future studies are needed to further define the clinical role of s-TNF-α measurement and to compare the clinical utility of 10 and 14-week ATI and s-IFX levels.

View details for DOI 10.1097/MIB.0000000000000769

View details for Web of Science ID 000377379500018

View details for PubMedID 27057683
Increases in Sex Hormones during Anti-Tumor Necrosis Factor a Therapy in Adolescents with Crohn's Disease. journal of pediatrics DeBoer, M. D., Thayu, M., Griffin, L. M., Baldassano, R. N., Denson, L. A., Zemel, B. S., Denburg, M. R., Agard, H. E., Herskovitz, R., Long, J., Leonard, M. B. 2016; 171: 146-152 e2
Abstract

To evaluate children with Crohn's disease for inverse relationships between systemic inflammatory cytokines and sex hormone regulation in the context of anti-tumor necrosis factor α (TNF-α) therapy.An observational study design was used to assess sex hormone and gonadotropin levels at the time of initiation of anti-TNF-α therapy and 10 weeks and 12 months later in 72 adolescents (Tanner stage 2-5) with Crohn's disease. Mixed-model linear regression was used to evaluate relationships between hormone levels, systemic inflammation, and dual-energy x-ray absorptiometry whole-body fat mass Z scores over the study interval.Sex hormone Z scores increased significantly during the 10-week induction interval: testosterone Z scores in male patients increased from a median of -0.36 to 0.40 (P < .05) and estradiol Z scores in females increased from -0.35 to -0.02 (P < .01). In mixed model regression, the pediatric Crohn's disease activity index score, cytokine levels, and measures of inflammation were significantly and negatively associated with sex hormone Z scores and with luteinizing hormone and follicle-stimulating hormone levels, adjusted for sex and Tanner stage. Sex hormone and gonadotropin levels were not associated with body mass index or fat mass Z-scores.Crohn's disease is associated with delayed maturation, and initiation of anti-TNF-α therapy was associated with significant and rapid increases in sex hormone and gonadotropin levels, in association with improvements in disease activity and measures of inflammation. These data are consistent with preclinical studies of the effects of inflammation on sex hormone regulation.

View details for DOI 10.1016/j.jpeds.2016.01.003

View details for PubMedID 26873656
Increases in Sex Hormones during Anti-Tumor Necrosis Factor a Therapy in Adolescents with Crohn's Disease JOURNAL OF PEDIATRICS DeBoer, M. D., Thayu, M., Griffin, L. M., Baldassano, R. N., Denson, L. A., Zemel, B. S., Denburg, M. R., Agard, H. E., Herskovitz, R., Long, J., Leonard, M. B. 2016; 171: 146-?
View details for DOI 10.1016/j.jpeds.2016.01.003

View details for Web of Science ID 000372753600032
Fracture Burden and Risk Factors in Childhood CKD: Results from the CKiD Cohort Study. Journal of the American Society of Nephrology Denburg, M. R., Kumar, J., Jemielita, T., Brooks, E. R., Skversky, A., Portale, A. A., Salusky, I. B., Warady, B. A., Furth, S. L., Leonard, M. B. 2016; 27 (2): 543-550
Abstract

Childhood chronic kidney disease (CHD) poses multiple threats to bone accrual; however, the associated fracture risk is not well characterized. This prospective cohort study included 537 CKD in Children (CKiD) participants. Fracture histories were obtained at baseline, at years 1, 3, and 5 through November 1, 2009, and annually thereafter. We used Cox regression analysis of first incident fracture to evaluate potential correlates of fracture risk. At enrollment, median age was 11 years, and 16% of patients reported a prior fracture. Over a median of 3.9 years, 43 males and 24 females sustained incident fractures, corresponding to 395 (95% confidence interval [95% CI], 293-533) and 323 (95% CI, 216-481) fractures per 10,000 person-years, respectively. These rates were 2- to 3-fold higher than published general population rates. The only gender difference in fracture risk was a 2.6-fold higher risk in males aged ≥15 years (570/10,000 person-years, adjusted P=0.04). In multivariable analysis, advanced pubertal stage, greater height Z-score, difficulty walking, and higher average log-transformed parathyroid hormone level were independently associated with greater fracture risk (all P≤0.04). Phosphate binder treatment (predominantly calcium-based) was associated with lower fracture risk (hazard ratio, 0.37; 95% CI, 0.15-0.91; P=0.03). Participation in more than one team sport was associated with higher risk (hazard ratio, 4.87; 95% CI, 2.21-10.75; P<0.001). In conclusion, children with CKD have a high burden of fracture. Regarding modifiable factors, higher average parathyroid hormone level was associated with greater risk of fracture, whereas phosphate binder use was protective in this cohort.

View details for DOI 10.1681/ASN.2015020152

View details for PubMedID 26139439
Association of 25-hydroxyvitamin D with areal and volumetric measures of bone mineral density and parathyroid hormone: impact of vitamin D-binding protein and its assays. Osteoporosis international Jemielita, T. O., Leonard, M. B., Baker, J., Sayed, S., Zemel, B. S., Shults, J., Herskovitz, R., Denburg, M. R. 2016; 27 (2): 617-626
Abstract

A comparison of the association of different forms of 25-hydroxyvitamin D [25(OH)D] with parathyroid hormone (PTH) and with areal and volumetric bone mineral density (BMD) demonstrated that bioavailable and free 25(OH)D do not provide a better index of vitamin D status in terms of bone health compared to total 25(OH)D.This study aims to compare measures of vitamin D-binding protein (DBP) using a monoclonal versus polyclonal ELISA and assess correlations of total versus estimated free and bioavailable 25(OH)D with BMD and PTH concentrations.DXA and peripheral quantitative CT (pQCT) scans were obtained in 304 adults (158 black, 146 white), ages 21-80 years. Free and bioavailable 25(OH)D were calculated from total 25(OH)D, DBP, and albumin concentrations. Multivariable linear regression with standardized beta coefficients was used to evaluate associations of bone measures and PTH with total, free, and bioavailable 25(OH)D.Measures of DBP obtained using a monoclonal versus polyclonal ELISA were not correlated (r s = 0.02, p = 0.76). Free and bioavailable 25(OH)D based on the polyclonal assay were lower in black versus white participants (p < 0.0001); this race difference was not evident using the monoclonal assay. Adjusted for age, sex, calcium intake, and race, all forms of 25(OH)D were negatively associated with PTH, but the absolute coefficient was greatest for total 25(OH)D (-0.34, p < 0.001) versus free/bioavailable 25(OH)D (-0.18/-0.24 depending on DBP assay, p ≤ 0.003). In analyses stratified on race, none of the measures of 25(OH)D were associated with BMD across DXA and pQCT sites.The monoclonal versus polyclonal ELISA yielded highly discrepant measures of DBP, particularly among black individuals, likely related to established race differences in DBP polymorphisms. Contrary to prior studies, our findings indicate that using DBP to estimate bioavailable and free 25(OH)D does not provide a better index of vitamin D status in terms of bone health.

View details for DOI 10.1007/s00198-015-3296-6

View details for PubMedID 26359185
Declining Rates of Inpatient Parathyroidectomy for Primary Hyperparathyroidism in the US. PloS one Kim, S. M., Shu, A. D., Long, J., Montez-Rath, M. E., Leonard, M. B., Norton, J. A., Chertow, G. M. 2016; 11 (8)
Abstract

Parathyroidectomy is the only curative therapy for patients with primary hyperparathyroidism. However, the incidence, correlates and consequences of parathyroidectomy for primary hyperparathyroidism across the entire US population are unknown. We evaluated temporal trends in rates of inpatient parathyroidectomy for primary hyperparathyroidism, and associated in-hospital mortality, length of stay, and costs. We used the Healthcare Cost and Utilization Project Nationwide Inpatient Sample (NIS) from 2002-2011. Parathyroidectomies for primary hyperparathyroidism were identified using International Classification of Diseases, Ninth Revision codes. Unadjusted and age- and sex- adjusted rates of inpatient parathyroidectomy for primary hyperparathyroidism were derived from the NIS and the annual US Census. We estimated 109,583 parathyroidectomies for primary hyperparathyroidism between 2002 and 2011. More than half (55.4%) of patients were younger than age 65, and more than three-quarters (76.8%) were female. The overall rate of inpatient parathyroidectomy was 32.3 cases per million person-years. The adjusted rate decreased from 2004 (48.3 cases/million person-years) to 2007 (31.7 cases/million person-years) and was sustained thereafter. Although inpatient parathyroidectomy rates declined over time across all geographic regions, a steeper decline was observed in the South compared to other regions. Overall in-hospital mortality rates were 0.08%: 0.02% in patients younger than 65 years and 0.14% in patients 65 years and older. Inpatient parathyroidectomy rates for primary hyperparathyroidism have declined in recent years.

View details for DOI 10.1371/journal.pone.0161192

View details for PubMedID 27529699

View details for PubMedCentralID PMC4986953
Quantification of skeletal growth, modeling, and remodeling by in vivo micro computed tomography BONE Altman, A. R., Tseng, W., de Bakker, C. M., Chandra, A., Lan, S., Huh, B. K., Luo, S., Leonard, M. B., Qin, L., Liu, X. S. 2015; 81: 370-379
View details for DOI 10.1016/j.bone.2015.07.037

View details for Web of Science ID 000365372800045

View details for PubMedID 26254742
Increased risk of hip fracture associated with dually treated HIV/hepatitis B virus coinfection JOURNAL OF VIRAL HEPATITIS Byrne, D. D., Newcomb, C. W., Carbonari, D. M., Nezamzadeh, M. S., Leidl, K. B., Herlim, M., Yang, Y. X., Hennessy, S., Kostman, J. R., Leonard, M. B., Localio, A. R., Lo Re, V. 2015; 22 (11): 936-947
View details for DOI 10.1111/jvh.12398

View details for Web of Science ID 000362450600009

View details for PubMedID 25754215
Insulin-like Growth Factor 1 and Adiponectin and Associations with Muscle Deficits, Disease Characteristics, and Treatments in Rheumatoid Arthritis. journal of rheumatology Baker, J. F., Von Feldt, J. M., Mostoufi-Moab, S., Kim, W., Taratuta, E., Leonard, M. B. 2015; 42 (11): 2038-2045
View details for DOI 10.3899/jrheum.150280

View details for PubMedID 26329340
Use of proton pump inhibitors is associated with fractures in young adults: a population-based study. Osteoporosis international Freedberg, D. E., Haynes, K., Denburg, M. R., Zemel, B. S., Leonard, M. B., Abrams, J. A., Yang, Y. 2015; 26 (10): 2501-2507
Abstract

Proton pump inhibitors (PPIs) are associated with risk for fracture in osteoporotic adults. In this population-based study, we found a significant association between PPIs and fracture in young adults, with evidence of a dose-response effect. Young adults who use PPIs should be cautioned regarding risk for fracture.Proton pump inhibitors (PPIs) are associated with fracture in adults with osteoporosis. Because PPI therapy may interfere with bone accrual and attainment of peak bone mineral density, we studied the association between use of PPIs and fracture in children and young adults.We conducted a population-based, case-control study nested within records from general medical practices from 1994 to 2013. Participants were 4-29 years old with ≥1 year of follow-up who lacked chronic conditions associated with use of long-term acid suppression. Cases of fracture were defined as the first incident fracture at any site. Using incidence density sampling, cases were matched with up to five controls by age, sex, medical practice, and start of follow-up. PPI exposure was defined as 180 or more cumulative doses of PPIs. Conditional logistic regression was used to estimate the odds ratio and confidence interval for use of PPIs and fracture.We identified 124,799 cases and 605,643 controls. The adjusted odds ratio for the risk of fracture associated with PPI exposure was 1.13 (95 % CI 0.92 to 1.39) among children aged <18 years old and 1.39 (95 % CI 1.26 to 1.53) among young adults aged 18-29 years old. In young adults but not children, we observed a dose-response effect with increased total exposure to PPIs (p for trend <0.001).PPI use was associated with fracture in young adults, but overall evidence did not support a PPI-fracture relationship in children. Young adults who use PPIs should be cautioned regarding potentially increased risk for fracture, even if they lack traditional fracture risk factors.

View details for DOI 10.1007/s00198-015-3168-0

View details for PubMedID 25986385
Bone Mineral Accrual Is Associated With Parathyroid Hormone and 1,25-Dihydroxyvitamin D Levels in Children and Adolescents. journal of clinical endocrinology & metabolism DeBoer, M. D., Weber, D. R., Zemel, B. S., Denburg, M. R., Herskovitz, R., Long, J., Leonard, M. B. 2015; 100 (10): 3814-3821
View details for DOI 10.1210/jc.2015-1637

View details for PubMedID 26241322
Type 1 Diabetes Is Associated With an Increased Risk of Fracture Across the Life Span: A Population-Based Cohort Study Using The Health Improvement Network (THIN) DIABETES CARE Weber, D. R., Haynes, K., Leonard, M. B., Willi, S. M., Denburg, M. R. 2015; 38 (10): 1913-1920
View details for DOI 10.2337/dc15-0783

View details for Web of Science ID 000361840500028

View details for PubMedID 26216874
Structural Bone Deficits in HIV/HCV-Coinfected, HCV-Monoinfected, and HIV-Monoinfected Women JOURNAL OF INFECTIOUS DISEASES Lo Re, V., Lynn, K., Stumm, E. R., Long, J., Nezamzadeh, M. S., Baker, J. F., Hoofnagle, A. N., Kapalko, A. J., Mounzer, K., Zemel, B. S., Tebas, P., Kostman, J. R., Leonard, M. B. 2015; 212 (6): 924-933
Abstract

Coinfection with human immunodeficiency virus (HIV) and hepatitis C virus (HCV) is associated with reduced bone mineral density (BMD) and increased fracture rates, particularly in women. The structural underpinnings for skeletal fragility in coinfected women have not been characterized. We used tibial peripheral quantitative computed tomography to evaluate skeletal parameters in women, by HIV/HCV status.We conducted a cross-sectional study among 50 HIV/HCV-coinfected, 51 HCV-monoinfected, and 50 HIV-monoinfected women. Tibial volumetric BMD and cortical dimensions were determined with peripheral quantitative computed tomography. Race-specific z scores for age were generated using 263 female reference participants without HIV infection or liver disease.Coinfected participants had lower mean z scores for trabecular volumetric BMD (-0.85), cortical volumetric BMD (-0.67), cortical area (-0.61), and cortical thickness (-0.77) than reference participants (all P < .001). The smaller cortical dimensions were due to greater mean z scores for endosteal circumference (+0.67; P < .001) and comparable z scores for periosteal circumference (+0.04; P = .87). Trabecular volumetric BMD was lower in coinfected than in HCV- or HIV-monoinfected participants. HCV-infected women with stage 3-4 liver fibrosis had lower mean z scores for trabecular volumetric BMD, cortical thickness, and total hip BMD those with stage 0-2 fibrosis.Compared with healthy reference patients, HIV/HCV-coinfected women had decreased tibial trabecular volumetric BMD, diminished cortical dimensions, and significant endocortical bone loss.

View details for DOI 10.1093/infdis/jiv147

View details for Web of Science ID 000361285600012

View details for PubMedID 25754980
Adverse Fat Depots and Marrow Adiposity Are Associated With Skeletal Deficits and Insulin Resistance in Long-Term Survivors of Pediatric Hematopoietic Stem Cell Transplantation JOURNAL OF BONE AND MINERAL RESEARCH Mostoufi-Moab, S., Magland, J., Isaacoff, E. J., Sun, W., Rajapakse, C. S., Zemel, B., Wehrli, F., Shekdar, K., Baker, J., Long, J., Leonard, M. B. 2015; 30 (9): 1657-1666
View details for DOI 10.1002/jbmr.2512

View details for Web of Science ID 000359866800013
Deficits in bone density and structure in children and young adults following Fontan palliation BONE Avitabile, C. M., Goldberg, D. J., Zemel, B. S., Brodsky, J. L., Dodds, K., Hayden-Rush, C., Whitehead, K. K., Goldmuntz, E., Rychik, J., Leonard, M. B. 2015; 77: 12-16
Abstract

Survival of patients with congenital heart disease has improved such that there are now more adults than children living with these conditions. Complex single ventricle congenital heart disease requiring Fontan palliation is associated with multiple risk factors for impaired bone accrual. Bone density and structure have not been characterized in these patients.Tibia peripheral quantitative computed tomography (pQCT) was used to assess trabecular and cortical volumetric bone mineral density (vBMD), cortical dimensions, and calf muscle area in 43 Fontan participants (5-33 years old), a median of 10 years following Fontan palliation. pQCT outcomes were converted to sex- and race-specific Z-scores relative to age based on >700 healthy reference participants. Cortical dimensions and muscle area were further adjusted for tibia length.Height Z-scores were lower in Fontan compared to reference participants (mean ± SD: -0.29 ± 1.00 vs. 0.25 ± 0.93, p < 0.001); BMI Z-scores were similar (0.16 ± 0.88 vs. 0.35 ± 1.02, p = 0.1). Fontan participants had lower trabecular vBMD Z-scores (-0.85 ± 0.96 vs. 0.01 ± 1.02, p < 0.001); cortical vBMD Z-scores were similar (-0.17 ± 0.98 vs. 0.00 ± 1.00, p = 0.27). Cortical dimensions were reduced with lower cortical area (-0.59 ± 0.84 vs. 0.00 ± 0.88, p<0.001) and periosteal circumference (-0.50 ± 0.82 vs. 0.00 ± 0.84, p < 0.001) Z-scores, compared to reference participants. Calf muscle area Z-scores were lower in the Fontan participants (-0.45 ± 0.98 vs. 0.00 ± 0.96, p = 0.003) and lower calf muscle area Z-scores were associated with smaller periosteal circumference Z-scores (R = 0.62, p < 0.001). Musculoskeletal deficits were not associated with age, Fontan characteristics, parathyroid hormone or vitamin D levels.Children and young adults demonstrate low trabecular vBMD, cortical structure and muscle area following Fontan. Muscle deficits were associated with smaller periosteal dimensions. Future studies should determine the fracture implications of these deficits and identify interventions to promote musculoskeletal development.

View details for DOI 10.1016/j.bone.2015.04.012

View details for Web of Science ID 000355717800003

View details for PubMedID 25882907
Fractures on bisphosphonates in osteoporosis pseudoglioma syndrome (OPPG): pQCT shows poor bone density and structure BONE Streeten, E. A., Ramirez, S., Eliades, M., Jaimungal, S., Chandrasekaran, S., Kathleen, R., Morton, D. H., Puffenberger, E. G., Herskovitz, R., Leonard, M. B. 2015; 77: 17-23
View details for DOI 10.1016/j.bone.2015.04.007

View details for Web of Science ID 000355717800004

View details for PubMedID 25892485
Fractures on bisphosphonates in osteoporosis pseudoglioma syndrome (OPPG): pQCT shows poor bone density and structure. Bone Streeten, E. A., Ramirez, S., Eliades, M., Jaimungal, S., Chandrasekaran, S., Kathleen, R., Holmes Morton, D., Puffenberger, E. G., Herskovitz, R., Leonard, M. B. 2015; 77: 17-23
Abstract

Osteoporosis pseudoglioma syndrome (OPPG) is a rare autosomal recessive disorder of childhood osteoporosis and blindness due to inactivating mutations in LDL receptor-like protein 5 (LRP5). We and others have reported improvement in areal bone mineral density (aBMD) by DXA in OPPG on short term bisphosphonates. Long-term data on bisphosphonate use in OPPG and measures of volumetric BMD (vBMD) and cortical structure are not available. In addition, no long-term DXA data on untreated OPPG is available. The aims of this study were to: (1) record low trauma fractures and longitudinal aBMD by DXA in 5 OPPG patients on chronic bisphosphonate treatment, and in 4 OPPG patients never treated (2) to perform tibia peripheral quantitative CT (pQCT) to evaluate volumetric bone mineral density (vBMD), cortical structure and calf muscle area in 6 OPPG patients and 14 unaffected first degree family members. pQCT results were converted to sex-specific Z-scores for age and adjusted for tibia length based on data in >700 reference participants. We observed 4 fractures (3 femoral shafts) in 3 OPPG patients while on bisphosphonates, after each achieved significant improvement in aBMD. OPPG participants had significantly lower mean trabecular vBMD (-1.51 vs. 0.17, p = 0.002), cortical area (-2.36 vs. 0.37; p < 0.001) and periosteal circumference (-1.86 vs. -0.31, p = 0.001) Z-scores, compared with unaffected participants and had a trend toward lower muscle area Z-score (-0.69 vs. 0.47, p = 0.12). These data demonstrate substantial bone fragility despite improvements in aBMD. The pQCT data provide insight into the fragility with substantial deficits in trabecular vBMD and cortical dimensions, consistent with OPPG effects of bone formation. Treatment that improves bone quality is needed to reduce fractures in OPPG.

View details for DOI 10.1016/j.bone.2015.04.007

View details for PubMedID 25892485
Improvements in Bone Density and Structure during Anti-TNF-a Therapy in Pediatric Crohn's Disease. journal of clinical endocrinology & metabolism Griffin, L. M., Thayu, M., Baldassano, R. N., DeBoer, M. D., Zemel, B. S., Denburg, M. R., Denson, L. A., Shults, J., Herskovitz, R., Long, J., Leonard, M. B. 2015; 100 (7): 2630-2639
Abstract

Pediatric Crohn's Disease (CD) is associated with deficits in trabecular bone mineral density (BMD) and cortical structure, potentially related to TNF-α effects to decrease bone formation and promote bone resorption.This study aimed to examine changes in bone density and structure in children and adolescents with CD following initiation of anti-TNF-α therapy.Participants (n = 74; age 5-21 years) with CD completed a 12-month prospective cohort study.Tibia peripheral quantitative computed tomography scans were obtained at initiation of anti-TNF-α therapy and 12 months later. Musculoskeletal outcomes were expressed as sex-and race-specific z scores relative to age, based on >650 reference participants.At baseline, CD participants had lower height, trabecular BMD, cortical area (due to smaller periosteal and larger endocortical circumferences), and muscle area z scores, compared with reference participants (all P < .01). Pediatric CD activity index decreased during the 10-week induction (P < .001), in association with subsequent gains in height, trabecular BMD, cortical area (due to recovery of endocortical bone), and muscle area z scores over 12 months (height P < .05; others P < .001). Bone-specific alkaline phosphatase levels, a biomarker of bone formation, increased a median of 75% (P < .001) during induction with associated 12-month improvements in trabecular BMD and cortical area z scores (both P < .001). Younger age was associated with greater increases in trabecular BMD z scores (P < .001) and greater linear growth with greater recovery of cortical area (P < .001).Anti-TNF-α therapy was associated with improvements in trabecular BMD and cortical structure. Improvements were greater in younger and growing participants, suggesting a window of opportunity for treatment of bone deficits.

View details for DOI 10.1210/jc.2014-4152

View details for PubMedID 25919459
The impact of vitamin D-3 supplementation on muscle function among HIV-infected children and young adults: a randomized controlled trial JOURNAL OF MUSCULOSKELETAL & NEURONAL INTERACTIONS Brown, J. C., Schall, J. I., Rutstein, R. M., Leonard, M. B., Zemel, B. S., Stallings, V. A. 2015; 15 (2): 145-153
Abstract

We tested the hypothesis that daily vitD3 supplementation increases neuromuscular motor skills, jump power, jump energy, muscular force, and muscular strength.This was a secondary analysis of a randomized controlled trial of 12-months of oral 7,000 IU/day vitD3 supplementation or placebo among 56 persons living with HIV aged 9-25 years. Neuromuscular motor skills were quantified using the Bruininks-Oseretsky Test of Motor Proficiency. Power was quantified using peak jump power, and energy was quantified using peak jump height. Muscular force was quantified using isometric ankle plantar- and dorsiflexion, isokinetic knee flexion and extension. Muscular strength was quantified using isometric handgrip strength.After 12-months, serum 25-hydroxyvitamin D [25(OH)D] was higher with supplementation versus placebo (β=12.1 ng/mL; P<0.001). In intention-to-treat analyses, supplementation improved neuromuscular motor skills versus placebo (β=1.14; P=0.041). We observed no effect of supplementation on jump power, jump energy, muscular force, or muscular strength outcomes versus placebo.Among HIV-infected children and young adults supplementation with daily high-dose vitD3 increased concentration of serum 25(OH)D and improved neuromuscular motor skills versus placebo.

View details for Web of Science ID 000356001800004

View details for PubMedID 26032206
Tibia and radius bone geometry and volumetric density in obese compared to non-obese adolescents. Bone Leonard, M. B., Zemel, B. S., Wrotniak, B. H., Klieger, S. B., Shults, J., Stallings, V. A., Stettler, N. 2015; 73: 69-76
Abstract

Childhood obesity is associated with biologic and behavioral characteristics that may impact bone mineral density (BMD) and structure. The objective was to determine the association between obesity and bone outcomes, independent of sexual and skeletal maturity, muscle area and strength, physical activity, calcium intake, biomarkers of inflammation, and vitamin D status. Tibia and radius peripheral quantitative CT scans were obtained in 91 obese (BMI>97th percentile) and 51 non-obese adolescents (BMI>5th and <85th percentiles). Results were converted to sex- and race-specific Z-scores relative to age. Cortical structure, muscle area and muscle strength (by dynamometry) Z-scores were further adjusted for bone length. Obese participants had greater height Z-scores (p<0.001), and advanced skeletal maturity (p<0.0001), compared with non-obese participants. Tibia cortical section modulus and calf muscle area Z-scores were greater in obese participants (1.07 and 1.63, respectively, both p<0.0001). Tibia and radius trabecular and cortical volumetric BMD did not differ significantly between groups. Calf muscle area and strength Z-scores, advanced skeletal maturity, and physical activity (by accelerometry) were positively associated with tibia cortical section modulus Z-scores (all p<0.01). Adjustment for muscle area Z-score attenuated differences in tibia section modulus Z-scores between obese and non-obese participants from 1.07 to 0.28. After multivariate adjustment for greater calf muscle area and strength Z-scores, advanced maturity, and less moderate to vigorous physical activity, tibia section modulus Z-scores were 0.32 (95% CI -0.18, 0.43, p=0.06) greater in obese, vs. non-obese participants. Radius cortical section modulus Z-scores were 0.45 greater (p=0.08) in obese vs. non-obese participants; this difference was attenuated to 0.14 with adjustment for advanced maturity. These findings suggest that greater tibia cortical section modulus in obese adolescents is attributable to advanced skeletal maturation and greater muscle area and strength, while less moderate to vigorous physical activities offset the positive effects of these covariates. The impact of obesity on cortical structure was greater at weight bearing sites.

View details for DOI 10.1016/j.bone.2014.12.002

View details for PubMedID 25497572
Tibia and radius bone geometry and volumetric density in obese compared to non-obese adolescents BONE Leonard, M. B., Zemel, B. S., Wrotniak, B. H., Klieger, S. B., Shults, J., Stallings, V. A., Stettler, N. 2015; 73: 69-76
View details for DOI 10.1016/j.bone.2014.12.002

View details for Web of Science ID 000350532800009

View details for PubMedID 25497572
Usefulness of Insulin like Growth Factor 1 as a Marker of Heart Failure in Children and Young Adults After the Fontan Palliation Procedure AMERICAN JOURNAL OF CARDIOLOGY Avitabile, C. M., Leonard, M. B., Brodsky, J. L., Whitehead, K. K., Ravishankar, C., Cohen, M. S., Gaynor, J. W., Rychik, J., Goldberg, D. J. 2015; 115 (6): 816-820
Abstract

Growth hormone and its mediator, insulinlike growth factor 1 (IGF-1), are key determinants of growth in children and young adults. As patients with Fontan physiology often experience diminished longitudinal growth, we sought to describe IGF-1 levels in this population and to identify factors associated with IGF-1 deficiency. Forty-one Fontan subjects ≥5 years were evaluated in this cross-sectional study. Age- and gender-specific height Z scores were generated using national data. Laboratory testing included IGF-1 and brain natriuretic peptide (BNP) levels. IGF-1 levels were converted to age-, gender-, and Tanner stage-specific Z scores. BNP levels were log transformed to achieve a normal distribution (log-BNP). Medical records were reviewed for pertinent clinical variables. Predictors of IGF-1 Z score were assessed through the Student t test and Pearson's correlation. Median age was 11.1 years (range 5.1 to 33.5 years), and time from Fontan was 8.2 years (1.1 to 26.7). Mean height Z score was -0.2 ± 0.9 with a mean IGF-1 Z score of -0.1 ± 1.3. There was no association between IGF-1 Z score and height Z score. Longer interval since Fontan (R = -0.32, p = 0.04), higher log-BNP (R = -0.40; p = 0.01), and lower indexed systemic flow on cardiac magnetic resonance (R = 0.55, p = 0.02) were associated with lower IGF-1 Z scores. In conclusion, in this cohort with Fontan physiology, higher BNP and lower systemic flow were associated with lower IGF-1 Z score. Longitudinal studies are needed to determine if these relations represent a mechanistic explanation for diminished growth in children with this physiology and with other forms of congenital heart disease.

View details for DOI 10.1016/j.amjcard.2014.12.041

View details for Web of Science ID 000351482700018

View details for PubMedID 25616534
Muscle Torque Relative to Cross-Sectional Area and the Functional Muscle-Bone Unit in Children and Adolescents With Chronic Disease JOURNAL OF BONE AND MINERAL RESEARCH Lee, D. Y., Wetzsteon, R. J., Zemel, B. S., Shults, J., Organ, J. M., Foster, B. J., Herskovitz, R. M., Foerster, D. L., Leonard, M. B. 2015; 30 (3): 575-583
Abstract

Measures of muscle mass or size are often used as surrogates of forces acting on bone. However, chronic diseases may be associated with abnormal muscle force relative to muscle size. The muscle-bone unit was examined in 64 children and adolescents with new-onset Crohn's disease (CD), 54 with chronic kidney disease (CKD), 51 treated with glucocorticoids for nephrotic syndrome (NS), and 264 healthy controls. Muscle torque was assessed by isometric ankle dynamometry. Calf muscle cross-sectional area (CSA) and tibia cortical section modulus (Zp) were assessed by quantitative CT. Log-linear regression was used to determine the relations among muscle CSA, muscle torque, and Zp, adjusted for tibia length, age, Tanner stage, sex, and race. Muscle CSA and muscle torque-relative-to-muscle CSA were significantly lower than controls in advanced CKD (CSA -8.7%, p = 0.01; torque -22.9%, p < 0.001) and moderate-to-severe CD (CSA -14.1%, p < 0.001; torque -7.6%, p = 0.05), but not in NS. Zp was 11.5% lower in advanced CKD (p = 0.005) compared to controls, and this deficit was attenuated to 6.7% (p = 0.05) with adjustment for muscle CSA. With additional adjustment for muscle torque and body weight, Zp was 5.9% lower and the difference with controls was no longer significant (p = 0.09). In participants with moderate-to-severe CD, Zp was 6.8% greater than predicted (p = 0.01) given muscle CSA and torque deficits (R(2) = 0.92), likely due to acute muscle loss in newly-diagnosed patients. Zp did not differ in NS, compared with controls. In conclusion, muscle torque relative to muscle CSA was significantly lower in CKD and CD, compared with controls, and was independently associated with Zp. Future studies are needed to determine if abnormal muscle strength contributes to progressive bone deficits in chronic disease, independent of muscle area. © 2014 American Society for Bone and Mineral Research.

View details for Web of Science ID 000350066900023

View details for PubMedID 25264231
Revisiting KDIGO clinical practice guideline on chronic kidney disease-mineral and bone disorder: a commentary from a Kidney Disease: Improving Global Outcomes controversies conference KIDNEY INTERNATIONAL Ketteler, M., Elder, G. J., Evenepoel, P., Ix, J. H., Jamal, S. A., Lafage-Proust, M., Shroff, R., Thadhani, R. I., Tonelli, M. A., Kasiske, B. L., Wheeler, D. C., Leonard, M. B. 2015; 87 (3): 502-508
Abstract

A new definition and classification of chronic kidney disease-mineral and bone disorder (CKD-MBD) was proposed in 2005 and it was later followed by a guideline publication on this topic from Kidney Disease: Improving Global Outcomes (KDIGO) in 2009. This work recognized that CKD-MBD is a syndrome of bone abnormalities, laboratory abnormalities, and vascular calcification linked to fractures, cardiovascular disease, and mortality. Because of limited data at the time of the original guideline systematic review, many of the recommendations were cautiously vague. KDIGO convened a Controversies Conference in October 2013 to review the CKD-MBD literature published since the 2009 guideline. Specifically, the objective of this conference was to determine whether sufficient new data had emerged to support a reassessment of the CKD-MBD guideline and if so to determine the scope of these potential revisions. This report summarizes the results of these proceedings, highlighting important new studies conducted in the interval since the original KDIGO CKD-MBD guideline.Kidney International advance online publication, 4 February 2015; doi:10.1038/ki.2014.425.

View details for DOI 10.1038/ki.2014.425

View details for Web of Science ID 000350533300006

View details for PubMedID 25651364
Muscle Torque Relative to Cross-Sectional Area and the Functional Muscle-Bone Unit in Children and Adolescents With Chronic Disease JOURNAL OF BONE AND MINERAL RESEARCH Lee, D. Y., Wetzsteon, R. J., Zemel, B. S., Shults, J., Organ, J. M., Foster, B. J., Herskovitz, R. M., Foerster, D. L., Leonard, M. B. 2015; 30 (3): 563-571
View details for Web of Science ID 000350066900020
Obesity Is Associated with Greater Valgus Knee Alignment in Pubertal Children, and Higher Body Mass Index Is Associated with Greater Variability in Knee Alignment in Girls JOURNAL OF RHEUMATOLOGY Bout-Tabaku, S., Shults, J., Zemel, B. S., Leonard, M. B., Berkowitz, R. I., Stettler, N., Burnham, J. M. 2015; 42 (1): 126-133
Abstract

In adults, osteoarthritis (OA) is associated with obesity and knee alignment. Whether knee alignment differences develop during childhood and are associated with obesity is unknown. We assessed the distribution of knee alignment in children and adolescents, and determined how knee alignment differs between obese and nonobese children.This cross-sectional study examined knee alignment in 155 healthy weight and 165 obese subjects. Knee alignment [metaphyseal-diaphyseal angle (MDA) and anterior tibiofemoral angle (ATFA)] and fat mass were measured using whole body dual-energy X-ray absorptiometry (DEXA). National reference data were used to generate age- and sex-specific body mass index (BMI, kg/m(2)) Z-scores. Multivariable linear regression was used to identify independent factors associated with ATFA and MDA.The mean MDA and ATFA were similar between obese and nonobese subjects. In stratified analyses, females had greater variability in MDA and ATFA values (p < 0.001 and p = 0.04, respectively) at higher BMI Z-scores. Compared with healthy weight controls, obese subjects had less valgus of the MDA prior to the onset of puberty (+ 2.0°, p = 0.001), but had greater valgus at later pubertal stages (-1.9°, p = 0.01).We found significantly greater variability in knee alignment among females at higher BMI Z-scores, and greater valgus alignment in obese adolescents in late puberty. The major limitation is the use of DEXA for assessment of alignment, which needs validation against longstanding radiographs. Longitudinal studies are needed to determine whether childhood obesity is a risk factor for progressive malalignment that may predispose to pain and risk of early osteoarthritis.

View details for DOI 10.3899/jrheum.131349

View details for Web of Science ID 000347127300022

View details for PubMedID 25362652
Are Men at Greater Risk of Lean Mass Deficits in Rheumatoid Arthritis? ARTHRITIS CARE & RESEARCH Baker, J. F., Long, J., Ibrahim, S., Leonard, M. B., Katz, P. 2015; 67 (1): 112-119
Abstract

We aimed to determine if there were sex differences in lean body mass (LBM) in patients with rheumatoid arthritis (RA) when compared with sex- and race-specific National Health and Nutrition Examination Survey (NHANES) reference data, and to investigate the impact of sex differences in risk factors for LBM deficits.Dual x-ray absorptiometry measures of whole body LBM and appendicular LBM (arms and legs, appendicular lean mass [ALM]) were obtained on a total of 190 subjects from 2 independent cohorts (141 from San Francisco [SF], 49 from Philadelphia [PA]), expressed as indices adjusted for height (LBM index and ALM index, kg/m(2) ), and converted to sex- and race-specific Z scores relative to age and based on NHANES data. Sarcopenia was defined using 4 different sex-specific definitions. Multivariable linear and logistic regression analyses adjusted for disease activity, disease duration, physical activity, anti-cyclic citrullinated peptide seropositivity, fat mass index, and glucocorticoid use.While there were significant differences between the 2 cohorts, ALM index Z scores were significantly lower in men compared to women in both (SF: -1.43 versus -0.43, P < 0.0001; PA: -0.83 versus -0.06, P = 0.03). Observed sex differences were significant after adjustment in multivariable analyses within both cohorts. Odds of sarcopenia were 3 to 8 times greater in men in the SF cohort. Men in the PA cohort also had a higher, but nonsignificant, risk of sarcopenia.RA is associated with significant LBM deficits, with greater deficits observed in men. Future study may help elucidate the mechanisms driving greater deficits among men.

View details for DOI 10.1002/acr.22396

View details for Web of Science ID 000346917200016

View details for PubMedID 25048740
Risk of Fracture in Urolithiasis: A Population-Based Cohort Study Using the Health Improvement Network CLINICAL JOURNAL OF THE AMERICAN SOCIETY OF NEPHROLOGY Denburg, M. R., Leonard, M. B., Haynes, K., Tuchman, S., Tasian, G., Shults, J., Copelovitch, L. 2014; 9 (12): 2133-2140
Abstract

Studies have shown decreased bone mineral density in individuals with urolithiasis, but their burden of fracture remains unclear. This study sought to determine whether urolithiasis is associated with increased fracture risk across the lifespan and to delineate sex effects.A population-based retrospective cohort study using The Health Improvement Network was performed. The median calendar year for the start of the observation period was 2004 (1994-2012). This study identified 51,785 participants with ≥1 of 87 diagnostic codes for urolithiasis and 517,267 randomly selected age-, sex-, and practice-matched participants. Cox regression was used to estimate the hazard ratio (HR) for first fracture. Fractures identified using diagnostic codes were classified by anatomic site.Median age was 53 years, and 67% of participants were men, confirming their greater urolithiasis burden. Median time from urolithiasis diagnosis to fracture was 10 years. The HR for fracture associated with urolithiasis differed by sex and age (P for interactions, P≤0.003). In men, the adjusted HR was greatest in adolescence (1.55; 95% confidence interval [95% CI], 1.07 to 2.25) with an overall HR of 1.10 (95% CI, 1.05 to 1.16). Urolithiasis was associated with higher fracture risk in women aged 30-79 years (HR, 1.17-1.52), and was highest in women aged 30-39 years (HR, 1.52; 95% CI, 1.23 to 1.87). Peak background fracture rates were highest in boys aged 10-19 years and in women aged 70-79 years. The incidence per 10,000 person-years in participants with versus without urolithiasis was 392 versus 258 in male participants aged 10-19 years, and 263 versus 218 in women aged 70-79 years. Distribution of fracture site within sex did not differ between participants with versus without urolithiasis.Urolithiasis was associated with higher incident fracture risk. The significantly higher risk at times of peak background fracture incidence in adolescent boys and elderly women has profound public health implications.

View details for DOI 10.2215/CJN.04340514

View details for Web of Science ID 000345947800018

View details for PubMedID 25341724
Urinary Creatinine Excretion, Bioelectrical Impedance Analysis, and Clinical Outcomes in Patients with CKD: The CRIC Study CLINICAL JOURNAL OF THE AMERICAN SOCIETY OF NEPHROLOGY Wilson, F. P., Xie, D., Anderson, A. H., Leonard, M. B., Reese, P. P., Delafontaine, P., Horwitz, E., Kallem, R., Navaneethan, S., Ojo, A., Porter, A. C., Sondheimer, J. H., Sweeney, H. L., Townsend, R. R., Feldman, H. I. 2014; 9 (12): 2095-2103
Abstract

Previous studies in chronic disease states have demonstrated an association between lower urinary creatinine excretion (UCr) and increased mortality, a finding presumed to reflect the effect of low muscle mass on clinical outcomes. Little is known about the relationship between UCr and other measures of body composition in terms of the ability to predict outcomes of interest.Using data from the Chronic Renal Insufficiency Cohort (CRIC), the relationship between UCr, fat free mass (FFM) as estimated by bioelectrical impedance analysis, and (in a subpopulation) whole-body dual-energy x-ray absorptiometry assessment of appendicular lean mass were characterized. The associations of UCr and FFM with mortality and ESRD were compared using Cox proportional hazards models.A total of 3604 CRIC participants (91% of the full CRIC cohort) with both a baseline UCr and FFM measurement were included; of these, 232 had contemporaneous dual-energy x-ray absorptiometry measurements. Participants were recruited between July 2003 and March 2007. UCr and FFM were modestly correlated (rho=0.50; P<0.001), while FFM and appendicular lean mass were highly correlated (rho=0.91; P<0.001). Higher urinary urea nitrogen, black race, younger age, and lower serum cystatin C level were all significantly associated with higher UCr. Over a median (interquartile range) of 4.2 (3.1-5.0) years of follow-up, 336 (9.3%) participants died and 510 (14.2%) reached ESRD. Lower UCr was associated with death and ESRD even after adjustment for FFM (adjusted hazard ratio for death per 1 SD higher level of UCr, 0.63 [95% confidence interval, 0.56 to 0.72]; adjusted hazard ratio for ESRD per 1 SD higher level of UCr, 0.70 [95% confidence interval, 0.63 to 0.75]).Among a cohort of individuals with CKD, lower UCr is associated with death and ESRD independent of FFM as assessed by bioelectrical impedance analysis.

View details for DOI 10.2215/CJN.03790414

View details for Web of Science ID 000345947800013

View details for PubMedID 25381342
Lean mass deficits, vitamin D status and exercise capacity in children and young adults after Fontan palliation HEART Avitabile, C. M., Leonard, M. B., Zemel, B. S., Brodsky, J. L., Lee, D., Dodds, K., Hayden-Rush, C., Whitehead, K. K., Goldmuntz, E., Paridon, S. M., Rychik, J., Goldberg, D. J. 2014; 100 (21): 1702-1707
Abstract

We sought to evaluate body composition in children and young adults with Fontan physiology. Leg lean mass (LM) deficits correlate with diminished exercise capacity in other populations and may contribute to exercise limitations in this cohort.This cross-sectional study included whole body dual energy X-ray absorptiometry scans in 50 Fontan participants ≥5 years, and measures of peak oxygen consumption (VO2) in 28. Whole body and leg LM (a measure of skeletal muscle) were converted to sex- and race-specific Z-scores, relative to age and stature, based on 992 healthy reference participants.Median age was 11.5 (range 5.1-33.5) years at 9.3 (1.1-26.7) years from Fontan. Height Z-scores were lower in Fontan compared with reference participants (-0.47±1.08 vs 0.25±0.93, p<0.0001). Body mass index Z-scores were similar (0.15±0.98 vs 0.35±1.02, p=0.18). LM Z-scores were lower in Fontan compared with reference participants (whole body LM -0.33±0.77 vs 0.00±0.74, p=0.003; leg LM -0.89±0.91 vs 0.00±0.89, p<0.0001). LM Z-scores were not associated with age or Fontan characteristics. Leg LM Z-scores were lower in vitamin D deficient versus sufficient Fontan participants (-1.47±0.63 vs -0.71±0.92, p=0.01). Median per cent predicted peak VO2 was 81% (range 13%-113%) and was associated with leg LM Z-scores (r=0.54, p=0.003).Following Fontan, children and young adults are shorter than their peers and have significant LM deficits. Skeletal muscle deficits were associated with vitamin D deficiency and reduced exercise capacity. Future studies should examine the progression of these deficits to further understand the contribution of peripheral musculature to Fontan exercise capacity.

View details for DOI 10.1136/heartjnl-2014-305723

View details for Web of Science ID 000345027300013

View details for PubMedID 24973081
Deficits in Muscle Mass, Muscle Density, and Modified Associations With Fat in Rheumatoid Arthritis ARTHRITIS CARE & RESEARCH Baker, J. F., Von Feldt, J., Mostoufi-Moab, S., Noaiseh, G., Taratuta, E., Kim, W., Leonard, M. B. 2014; 66 (11): 1612-1618
Abstract

To quantify muscle outcomes, independent of fat mass, in rheumatoid arthritis (RA) patients compared to healthy controls.Quantitative computed tomography scans measured calf muscle and fat cross-sectional area (CSA) and muscle density (an index of intramuscular adipose tissue), and isometric dynamometry was used to measure ankle muscle strength in 50 participants with RA ages 18-70 years and 500 healthy controls. Multivariable linear regression models assessed muscle deficits in RA after adjusting for group differences in adiposity and assessing for an altered muscle-fat association. Associations between RA disease characteristics and fat-adjusted muscle outcomes were also assessed.Compared to controls, RA subjects had significantly greater body mass index (BMI) and fat area, and lower muscle area, muscle density, and muscle strength (P < 0.001 for all). Strength deficits were eliminated with adjustment for the smaller muscle area. The magnitude of muscle deficits, relative to controls, was significantly greater (P < 0.03 for interaction) in participants with lower fat area and BMI. Among those in the lower tertiles of adiposity, RA subjects demonstrated more significant deficits compared to controls with similar adiposity. In contrast, among those in the highest tertile for adiposity, RA was not associated with muscle deficits. Among RA, greater Sharp/van der Heijde scores were associated with lower muscle CSA and muscle density. Greater disease activity and disability were associated with low muscle density.Deficits in muscle area and muscle density are present in RA patients compared to controls and are most pronounced in subjects with low fat mass. Greater joint destruction is associated with greater muscle deficits.

View details for DOI 10.1002/acr.22328

View details for Web of Science ID 000344334200003

View details for PubMedID 24664868
A Comparison of Fat and Lean Body Mass Index to BMI for the Identification of Metabolic Syndrome in Children and Adolescents JOURNAL OF CLINICAL ENDOCRINOLOGY & METABOLISM Weber, D. R., Leonard, M. B., Shults, J., Zemel, B. S. 2014; 99 (9): 3208-3216
Abstract

The use of body mass index (BMI) to assess risk for cardiometabolic disease in the pediatric population may be limited by a failure to differentiate between fat and lean body mass.The objectives of the study were to identify biologically based criteria for the definition of obesity using fat (FMI) and lean body mass index (LBMI) and to compare the ability of FMI and LBMI to BMI to identify the presence of metabolic syndrome (MetSyn).This was a cross-sectional study using National Health and Nutrition Examination Survey 1999-2006 data.A total of 3004 participants aged 12-20 years with dual-energy X-ray absorptiometry body composition and fasting laboratory data participated in the study.Adjusted odds ratios for MetSyn according to FMI and LBMI status and area under the curve for the identification of MetSyn were measured.Receiver-operating characteristic curve analyses identified the 80th percentile for FMI and the 74th percentile for LBMI as the optimal cut points for the identification of MetSyn. There was no difference in the area under the curve for FMI [0.867; 95% confidence interval (CI) 0.838-0.891] vs BMI (0.868; 95% CI 0.837-0.894) Z-scores for MetSyn discrimination. Separate multivariate regression models identified odds ratios for the identification of MetSyn of 6.2 (95% CI 3.3-11.5) for BMI-Z, 6.4 (95% CI 3.7-11.1) for FMI-Z, and 4.6 (95% CI 3.0-7.1) for LBMI-Z. Models containing both FMI-Z and LBMI-Z revealed that greater LBMI-Z was associated with greater odds of low high-density lipoprotein (1.5; 95% CI 1.2-1.9), high blood pressure (1.8; 95% CI 1.1-2.9), and insulin resistance (1.8; 95% CI 1.4-2.5), independent of FMI-Z.The use of FMI and LBMI does not improve upon BMI for the identification of MetSyn in the pediatric population. Unexpectedly, higher LBMI was associated with greater odds of multiple cardiometabolic risk factors independent of FMI. The use of FMI and LBMI allow for the independent evaluation of relationships between body compartments and disease and warrants future research.

View details for DOI 10.1210/jc.2014-1684

View details for Web of Science ID 000342341400058

View details for PubMedID 24926951
Risk of hip fracture associated with untreated and treated chronic hepatitis B virus infection JOURNAL OF HEPATOLOGY Byrne, D. D., Newcomb, C. W., Carbonari, D. M., Nezamzadeh, M. S., Leidl, K. B., Herlim, M., Yang, Y., Hennessy, S., Kostman, J. R., Leonard, M. B., Localio, A. R., Lo Re, V. 2014; 61 (2): 210-218
Abstract

Chronic hepatitis B (CHB) infection is associated with reduced bone mineral density, but its association with fractures is unknown. Our objectives were to determine whether untreated or treated CHB-infected persons are at increased risk for hip fracture compared to uninfected persons.We conducted a cohort study among 18,796 untreated CHB-infected, 7777 treated CHB-infected, and 979,751 randomly sampled uninfected persons within the U.S. Medicaid populations of California, Florida, New York, Ohio, and Pennsylvania (1999-2007). CHB infection was defined by two CHB diagnoses recorded >6 months apart and was classified as treated if a diagnosis was recorded and antiviral therapy was dispensed. After propensity score matching of CHB-infected and uninfected persons, Cox regression was used to estimate hazard ratios (HRs) with 95% confidence intervals (CIs) of incident hip fracture in: (1) untreated CHB-infected vs. uninfected, and (2) treated CHB-infected vs. uninfected patients.Untreated CHB-infected patients of black race had a higher rate of hip fracture than uninfected black persons (HR, 2.55 [95% CI, 1.42-4.58]). Compared to uninfected persons, relative hazards of hip fracture were increased for untreated white (HR, 1.26 [95% CI, 0.98-1.62]) and Hispanic (HR, 1.36 [95% CI, 0.77-2.40]) CHB-infected patients, and treated black (HR, 3.09 [95% CI, 0.59-16.22]) and white (HR, 1.90 [95% CI, 0.81-4.47]) CHB-infected patients, but these associations were not statistically significant.Among U.S. Medicaid enrollees, untreated CHB-infected patients of black race had a higher risk of hip fracture than uninfected black persons.

View details for DOI 10.1016/j.jhep.2014.04.001

View details for Web of Science ID 000339775700008

View details for PubMedID 24713185
Changes in trabecular bone density in incident pediatric Crohn's disease: a comparison of imaging methods OSTEOPOROSIS INTERNATIONAL Tsampalieros, A., Berkenstock, M. K., Zemel, B. S., Griffin, L., Shults, J., Burnham, J. M., Baldassano, R. N., Leonard, M. B. 2014; 25 (7): 1875-1883
Abstract

This study of changes in dual energy x-ray absorptiometry (DXA) spine BMD following diagnosis and treatment for childhood Crohn's disease demonstrated that changes in conventional posteroanterior BMD results were confounded by impaired growth, and suggested that lateral spine measurements and strategies to estimate volumetric BMD were more sensitive to disease and treatment effects.We previously reported significant increases in peripheral quantitative CT (pQCT) measures of trabecular volumetric bone mineral density (vBMD) following diagnosis and treatment of pediatric Crohn's disease (CD). The objective of this study was to compare pQCT trabecular vBMD and three DXA measures of spine BMD in this cohort: (1) conventional posteroanterior BMD (PA-BMD), (2) PA-BMD adjusted for height Z (PA-BMDHtZ), and (3) width-adjusted volumetric BMD (WA-BMD) estimated from PA and lateral scans.Spine DXA [lumbar (L1-4) for posteroanterior and L3 for lateral] and tibia pQCT scans were obtained in 65 CD subjects (ages 7-18 years) at diagnosis and 12 months later. BMD results were converted to sex, race, and age-specific Z-scores based on reference data in >650 children (ages 5-21 years). Multivariable linear regression models identified factors associated with BMD Z-scores.At CD diagnosis, all BMD Z-scores were lower compared with the reference children (all p values <0.01). The pQCT vBMD Z-scores (-1.46 ± 1.30) were lower compared with DXA PA-BMD (-0.75 ± 0.98), PA-BMDHtZ (-0.53 ± 0.87), and WA-BMD (-0.61 ± 1.10) among CD participants. Only PA-BMD Z-scores were correlated with height Z-scores at baseline (R = 0.47, p < 0.0001). pQCT and WA-BMD Z-scores increased significantly over 12 months to -1.04 ± 1.26 and -0.20 ± 1.14, respectively. Changes in all four BMD Z-scores were positively associated with changes in height Z-scores (p < 0.05). Glucocorticoid doses were inversely associated with changes in WA-BMD (p < 0.01) only.Conventional and height Z-score-adjusted PA DXA methods did not demonstrate the significant increases in trabecular vBMD noted on pQCT and WA-BMD scans. WA-BMD captured glucocorticoid effects, potentially due to isolation of the vertebral body on the lateral projection. Future studies are needed to identify the BMD measure that provides greatest fracture discrimination in CD.

View details for DOI 10.1007/s00198-014-2701-x

View details for Web of Science ID 000337034600007

View details for PubMedID 24760243
Serum Aldosterone and Death, End-Stage Renal Disease, and Cardiovascular Events in Blacks and Whites Findings From the Chronic Renal Insufficiency Cohort (CRIC) Study HYPERTENSION Deo, R., Yang, W., Khan, A. M., Bansal, N., Zhang, X., Leonard, M. B., Keane, M. G., Soliman, E. Z., Steigerwalt, S., Townsend, R. R., Shlipak, M. G., Feldman, H. I. 2014; 64 (1): 103-110
Abstract

Prior studies have demonstrated that elevated aldosterone concentrations are an independent risk factor for death in patients with cardiovascular disease. Limited studies, however, have evaluated systematically the association between serum aldosterone and adverse events in the setting of chronic kidney disease. We investigated the association between serum aldosterone and death and end-stage renal disease in 3866 participants from the Chronic Renal Insufficiency Cohort. We also evaluated the association between aldosterone and incident congestive heart failure and atherosclerotic events in participants without baseline cardiovascular disease. Cox proportional hazards models were used to evaluate independent associations between elevated aldosterone concentrations and each outcome. Interactions were hypothesized and explored between aldosterone and sex, race, and the use of loop diuretics and renin-angiotensin-aldosterone system inhibitors. During a median follow-up period of 5.4 years, 587 participants died, 743 developed end-stage renal disease, 187 developed congestive heart failure, and 177 experienced an atherosclerotic event. Aldosterone concentrations (per SD of the log-transformed aldosterone) were not an independent risk factor for death (adjusted hazard ratio, 1.00; 95% confidence interval, 0.93-1.12), end-stage renal disease (adjusted hazard ratio, 1.07; 95% confidence interval, 0.99-1.17), or atherosclerotic events (adjusted hazard ratio, 1.04; 95% confidence interval, 0.85-1.18). Aldosterone was associated with congestive heart failure (adjusted hazard ratio, 1.21; 95% confidence interval, 1.02-1.35). Among participants with chronic kidney disease, higher aldosterone concentrations were independently associated with the development of congestive heart failure but not for death, end-stage renal disease, or atherosclerotic events. Further studies should evaluate whether mineralocorticoid receptor antagonists may reduce adverse events in individuals with chronic kidney disease because elevated cortisol levels may activate the mineralocorticoid receptor.

View details for DOI 10.1161/HYPERTENSIONAHA.114.03311

View details for Web of Science ID 000337700400018

View details for PubMedID 24752431
Changes in Vitamin D-Related Mineral Metabolism After Induction With Anti-Tumor Necrosis Factor-alpha Therapy in Crohn's Disease JOURNAL OF CLINICAL ENDOCRINOLOGY & METABOLISM Augustine, M. V., Leonard, M. B., Thayu, M., Baldassano, R. N., de Boer, I. H., Shults, J., Denson, L. A., DeBoer, M. D., Herskovitz, R., Denburg, M. R. 2014; 99 (6): E991-E998
Abstract

Preclinical studies suggest that TNF-α suppresses PTH synthesis, inhibits renal 1α-hydroxylase activity, and impairs fibroblast growth factor 23 (FGF23) degradation. The impact of inflammation on vitamin D and mineral metabolism has not been well-characterized in Crohn's disease (CD).The objective of the study was to assess short-term changes in vitamin D-related mineral metabolism in CD after anti-TNF-α induction therapy.Eighty-seven CD participants, aged 5-39 years, were assessed at the initiation of anti-TNF-α therapy and 10 weeks later.Indices of clinical disease activity and serum concentrations of vitamin D metabolites, vitamin D-binding protein (DBP), calcium, PTH, FGF23, IL-6, and TNF-α were measured at each visit. A multivariable generalized estimating equation (GEE) regression analysis was used to examine the correlates of PTH and 1,25-dihydroxyvitamin D [1,25(OH)2D] concentrations at each visit.After anti-TNF-α therapy, cytokines and inflammatory markers [IL-6, TNF-α, erythrocyte sedimentation rate (ESR), and C-reactive protein (CRP)] concentrations decreased (all P < .0001), and PTH and 1,25(OH)2D concentrations increased (median 21 vs 30 pg/mL, P < .0001, and median 41.7 vs 48.1 pg/mL, P = .014, respectively). Levels of 25-hydroxyvitamin D [25(OH)D], 24,25-dihydroxyvitamin D, DBP, and FGF23 did not change. In GEE analyses, higher IL-6, TNF-α, ESR, and CRP were associated with lower PTH concentrations (all P < .001), adjusted for corrected calcium and 25(OH)D levels. Higher PTH was associated with higher 1,25(OH)2D concentrations (P < .001) at each visit, independent of 25(OH)D concentrations. Higher levels of all inflammatory markers were associated with lower 1,25(OH)2D concentrations (all P < .05). However, when PTH was added to these models, the inflammatory markers (with the exception of CRP) were no longer significantly associated with 1,25(OH)2D.Greater inflammation was associated with lower PTH and 1,25(OH)2D concentrations. After anti-TNF-α induction, PTH and 1,25(OH)2D concentrations increased without concomitant changes in 25(OH)D and FGF23, consistent with effects of inflammation on PTH and thereby renal conversion of 25(OH)D to 1,25(OH)2D.

View details for DOI 10.1210/jc.2013-3846

View details for Web of Science ID 000342340500007

View details for PubMedID 24617709
Prevalence of diagnosed chronic hepatitis B infection among US Medicaid enrollees, 2000-2007 29th International Conference on Pharmacoepidemiology and Therapeutic Risk Management Byrne, D. D., Newcomb, C. W., Carbonari, D. M., Nezamzadeh, M. S., Leidl, K. B., Herlim, M., Yang, Y., Hennessy, S., Kostman, J. R., Leonard, M. B., Localio, R., Lo Re, V. ELSEVIER SCIENCE INC. 2014: 418–23
Abstract

Few population-based studies have estimated the number of persons diagnosed with chronic hepatitis B (CHB) infection in the United States. Our objective was to estimate the prevalence of diagnosed CHB infection among persons enrolled in the U.S. Medicaid programs of California, Florida, New York, Ohio, and Pennsylvania between 2000 and 2007. As part of our analyses, we confirmed the accuracy of CHB diagnoses within the Medicaid database.CHB infection was defined by the presence of two outpatients CHB diagnoses recorded more than 6 months apart. Two clinicians reviewed the medical records of a random sample of patients who met this definition to confirm the diagnosis, which enabled calculation of the positive predictive value (PPV). The period prevalence of diagnosed CHB infection among Medicaid enrollees with at least 6 months of membership from 2000 to 2007 was then estimated, adjusting for both the PPV and estimated sensitivity of our definition of CHB infection.The definition of CHB infection accurately identified clinician-confirmed cases (PPV, 96.3%; 95% confidence interval [CI], 87.3-99.5). Using this definition, 31,046 cases of CHB were diagnosed among 31,358,010 eligible Medicaid members from the five states (prevalence, 9.9 [95% CI, 9.8-10.0] per 10,000). Adjusting for the PPV and estimated sensitivity of our CHB definition, the prevalence of diagnosed CHB infection was 15.6 (95% CI, 15.4-15.7) per 10,000.Two outpatient CHB diagnoses recorded more than 6 months apart validly identified clinician-confirmed CHB. The prevalence of diagnosed CHB infection among U.S. Medicaid enrollees was 15.6 per 10,000.

View details for DOI 10.1016/j.annepidem.2014.02.013

View details for Web of Science ID 000336638300002

View details for PubMedID 24703196
Increasing Use of Vitamin D Supplementation in the Chronic Renal Insufficiency Cohort Study JOURNAL OF RENAL NUTRITION Mariani, L. H., White, M. T., Shults, J., Anderson, C. A., Feldman, H. I., Wolf, M., Reese, P. P., Denburg, M. R., Townsend, R. R., Lo, J. C., Cappola, A. R., Carlow, D., Gadegbeku, C. A., Steigerwalt, S., Leonard, M. B. 2014; 24 (3): 186-193
Abstract

This study examined rates and determinants of vitamin D supplementation among Chronic Renal Insufficiency Cohort (CRIC) participants and determined the association between dose and 25-hydroxyvitamin D (25(OH)D) level. The 2010 Institute of Medicine Report noted a significant increase in vitamin D supplementation in the general population, but use in chronic kidney disease (CKD) is unknown.CRIC is a multicenter prospective observational cohort study of 3,939 participants with a median baseline age of 60 and an estimated glomerular filtration rate (eGFR) of 42.1 mL/minute per 1.73 m2. Of the cohort, 54.9% was male, 42.1% were Black, and 48.4% were diabetic. Multivariable logistic generalized estimating equations were used to examine determinants of supplementation use assessed annually between 2003 and 2011. Cross-sectional linear regression models, based on a subset of 1,155 participants, assessed associations between supplement dose and 25(OH)D level, measured by high-performance liquid chromatography coupled with tandem mass spectrometry.The proportion of participants reporting supplement use increased (P < .0001), from 10% at baseline to 44% at 7-year follow-up visits. This was largely due to initiation of products containing only ergocalciferol or cholecalciferol. The odds of supplementation were greater in older, female, non-Black, married participants with greater education and lower body mass index. Among participants taking supplementation, dose was positively associated with 25(OH)D level, adjusted for race, season, diabetes, dietary intake, eGFR, and proteinuria. Only 3.8% of non-Black and 16.5% of Black participants taking a supplement were deficient (<20 ng/mL), whereas 22.7% of non-Black and 62.4% of black participants not reporting supplement use were deficient.Vitamin D supplementation rates rose significantly among CRIC participants over 7 years of follow-up and were associated with greater serum 25(OH)D levels. Studies of vitamin D levels on clinical outcomes in CKD and future vitamin D interventional studies should consider these changes in supplementation practices.

View details for DOI 10.1053/j.jrn.2014.01.015

View details for Web of Science ID 000335313500009

View details for PubMedID 24613295
2013 Pediatric Position Development Conference: Executive Summary and Reflections JOURNAL OF CLINICAL DENSITOMETRY Gordon, C. M., Leonard, M. B., Zemel, B. S. 2014; 17 (2): 219-224
Abstract

The International Society for Clinical Densitometry (ISCD) convened its second Pediatric Position Development Conference (PDC) on October 2-3, 2013 in Baltimore, MD. The conference was co-sponsored by the American Society for Bone and Mineral Research (ASBMR) and was held immediately before their annual meeting. The aim of a PDC is to make recommendations for standards in the field of bone densitometry. The recommendations address issues such as quality control, data acquisition and analysis, and the interpretation and reporting of bone densitometric results. In 2007, ISCD convened its first Pediatric PDC to address issues specific to skeletal health assessments in children and adolescents. The 2013 Pediatric PDC focused on advances in the field since that initial conference that would lead to revisions of the original positions. Topics for consideration were developed by the ISCD and its Scientific Advisory Committee. Clinically relevant questions related to each topic were assigned to task forces for a comprehensive review of the medical literature and subsequent presentation of reports to an international panel of experts. Expert panelists included representatives from both the ISCD and ASBMR. The recommendations of the PDC Expert Panel were subsequently reviewed by the ISCD Board of Directors and positions accepted by majority vote. The approved recommendations became the Official Positions of the ISCD. The positions are to be submitted to the ASBMR for its consideration for endorsement. Topics considered at the Pediatric PDC included fracture prediction and definition of osteoporosis, dual-energy X-ray absorptiometry assessment in chronic diseases that may affect the skeleton, dual-energy X-ray absorptiometry interpretation and reporting, quantitative computed tomography measurements, and densitometry in infants and young children. We discuss potential implications of the new recommendations and factors leading to a change in the wording of these positions, considering the science that has evolved over the past 6yr.

View details for DOI 10.1016/j.jocd.2014.01.007

View details for Web of Science ID 000335933500001

View details for PubMedID 24657108
Bone Health in Children and Adolescents With Chronic Diseases That May Affect the Skeleton: The 2013 ISCD Pediatric Official Positions JOURNAL OF CLINICAL DENSITOMETRY Bianchi, M. L., Leonard, M. B., Bechtold, S., Hoegler, W., Mughal, M. Z., Schoenau, E., Sylvester, F. A., Vogiatzi, M., van den Heuvel-Eibrink, M. M., Ward, L. 2014; 17 (2): 281-294
View details for DOI 10.1016/j.jocd.2014.01.005

View details for Web of Science ID 000335933500006
Bone health in children and adolescents with chronic diseases that may affect the skeleton: the 2013 ISCD Pediatric Official Positions. Journal of clinical densitometry Bianchi, M. L., Leonard, M. B., Bechtold, S., Högler, W., Mughal, M. Z., Schönau, E., Sylvester, F. A., Vogiatzi, M., van den Heuvel-Eibrink, M. M., Ward, L. 2014; 17 (2): 281-294
Abstract

The aim of this Task Force was to review the use of dual-energy X-ray absorptiometry (DXA) in children and adolescents with underlying chronic diseases that pose risk factors for compromised bone health, such as inflammation, glucocorticoid therapy, or decreased mobility. The Task Force systematically analyzed more than 270 studies, with an emphasis on those published in the interval since the original 2007 Position Statements. Important developments over this period included prospective cohort studies demonstrating that DXA measures of areal bone mineral density (aBMD) predicted incident fractures and the development of robust reference data and strategies to adjust for bone size in children with growth impairment. In this report, we summarize the current literature on the relationship between DXA-based aBMD and both fracture (vertebral and non-vertebral) outcomes and non-fracture risk factors (e.g., disease characteristics, ambulatory status, and glucocorticoid exposure) in children with chronic illnesses. Most publications described the aBMD profile of children with underlying diseases, as well as the cross-sectional or longitudinal relationship between aBMD and clinically relevant non-fracture outcomes. Studies that addressed the relationship between aBMD and prevalent or incident fractures in children with chronic illnesses are now emerging. In view of these updated data, this report provides guidelines for the use of DXA-based aBMD in this setting. The initial recommendation that DXA is part of a comprehensive skeletal healthy assessment in patients with increased risk of fracture is unchanged. Although the prior guidelines recommended DXA assessment in children with chronic diseases at the time of clinical presentation with ongoing monitoring, this revised Position Statement focuses on the performance of DXA when the patient may benefit from interventions to decrease their elevated risk of a clinically significant fracture and when the DXA results will influence that management.

View details for DOI 10.1016/j.jocd.2014.01.005

View details for PubMedID 24656723
Changes in DXA and Quantitative CT Measures of Musculoskeletal Outcomes Following Pediatric Renal Transplantation AMERICAN JOURNAL OF TRANSPLANTATION Tsampalieros, A., Griffin, L., Terpstra, A. M., Kalkwarf, H. J., Shults, J., Foster, B. J., Zemel, B. S., Foerster, D. L., Leonard, M. B. 2014; 14 (1): 124-132
Abstract

This prospective study evaluated changes in dual energy X-ray absorptiometry (DXA) whole body bone mineral content (WB-BMC) and spine areal bone mineral density (spine-BMD), and tibia quantitative computed tomography (QCT) trabecular and cortical volumetric BMD and cortical area in 56 children over 12 months following renal transplantation. At transplant, spine-BMD Z-scores were greater in younger recipients (<13 years), versus 898 reference participants (p < 0.001). In multivariate models, greater decreases in spine-BMD Z-scores were associated with greater glucocorticoid dose (p < 0.001) and declines in parathyroid hormone levels (p = 0.008). Changes in DXA spine-BMD and QCT trabecular BMD were correlated (r = 0.47, p < 0.01). At 12 months, spine-BMD Z-scores remained elevated in younger recipients, but did not differ in older recipients (≥ 13) and reference participants. Baseline WB-BMC Z-scores were significantly lower than reference participants (p = 0.02). Greater glucocorticoid doses were associated with declines in WB-BMC Z-scores (p < 0.001) while greater linear growth was associated with gains in WB-BMC Z-scores (p = 0.01). Changes in WB-BMC Z-scores were associated with changes in tibia cortical area Z-scores (r = 0.52, p < 0.001), but not changes in cortical BMD Z-scores. Despite resolution of muscle deficits, WB-BMC Z-scores at 12 months remained significantly reduced. These data suggest that spine and WB DXA provides insight into trabecular and cortical outcomes following pediatric renal transplantation.

View details for DOI 10.1111/ajt.12524

View details for Web of Science ID 000328597900017

View details for PubMedID 24298998
Childhood Cancer Survivors Exposed to Total Body Irradiation Are At Significant Risk For Slipped Capital Femoral Epiphysis During Recombinant Growth Hormone Therapy PEDIATRIC BLOOD & CANCER Mostoufi-Moab, S., Isaacoff, E. J., Spiegel, D., Gruccio, D., Ginsberg, J. P., Hobbie, W., Shults, J., Leonard, M. B. 2013; 60 (11): 1766-1771
Abstract

Childhood cancer survivors treated with cranial or total body irradiation (TBI) are at risk for growth hormone deficiency (GHD). Recombinant growth hormone (rhGH) therapy is associated with slipped capital femoral epiphysis (SCFE). We compared the incidence of SCFE after TBI versus cranial irradiation (CI) in childhood cancer survivors treated with rhGH.Retrospective cohort study (1980-2010) of 119 survivors treated with rhGH for irradiation-induced GHD (56 TBI; 63 CI). SCFE incidence rates were compared in CI and TBI recipients, and compared with national registry SCFE rates in children treated with rhGH for idiopathic GHD.Median survivor follow-up since rhGH initiation was 4.8 (range 0.2-18.3) years. SCFE was diagnosed in 10 subjects post-TBI and none after CI (P < 0.001). All 10 subjects had atypical valgus SCFE, and 7 were bilateral at presentation. Within TBI recipients, age at cancer diagnosis, sex, race, underlying malignancy, age at radiation, and age at initiation of rhGH did not differ significantly between those with versus without SCFE. The mean (SD) age at SCFE diagnosis was 12.3 (2.7) years and median duration of rhGH therapy to SCFE was 1.8 years. The SCFE incidence rate after TBI exposure was 35.9 per 1,000 person years, representing a 211-fold greater rate than reported in children treated with rhGH for idiopathic GH deficiency.The markedly greater SCFE incidence rate in childhood cancer survivors with TBI-associated GHD, compared with rates in children with idiopathic GHD, suggests that cancer treatment effects to the proximal femoral physis may contribute to SCFE. Pediatr Blood Cancer. © 2013 Wiley Periodicals, Inc.

View details for DOI 10.1002/pbc.24667

View details for Web of Science ID 000324299800014

View details for PubMedID 23818448
Reply to RF Burton. American journal of clinical nutrition Weber, D. R., Moore, R. H., Leonard, M. B., Zemel, B. S. 2013; 98 (5): 1368-1369
View details for DOI 10.3945/ajcn.113.068379

View details for PubMedID 24142240
Vitamin D bioavailability and catabolism in pediatric chronic kidney disease PEDIATRIC NEPHROLOGY Denburg, M. R., Kalkwarf, H. J., de Boer, I. H., Hewison, M., Shults, J., Zemel, B. S., Stokes, D., Foerster, D., Laskin, B., Ramirez, A., Leonard, M. B. 2013; 28 (9): 1843-1853
Abstract

Vitamin D-binding protein (DBP) and catabolism have not been examined in the clinical setting of childhood chronic kidney disease (CKD).The concentrations of serum vitamin D {25-hydroxyvitamin D [25(OH)D], 1,25-dihydroxyvitamin D [1,25(OH)(2)D], 24,25-dihydroxyvitamin D [24,25(OH)(2)D]}, DBP, intact parathyroid hormone (iPTH), and fibroblast growth factor-23 (FGF23) were measured in 148 participants with CKD stages 2-5D secondary to congenital anomalies of the kidney/urinary tract (CAKUT), glomerulonephritis (GN), or focal segmental glomerulosclerosis (FSGS). Free and bioavailable 25(OH)D concentrations were calculated using total 25(OH)D, albumin, and DBP concentrations.The concentrations of all vitamin D metabolites were lower with more advanced CKD (p < 0.001) and glomerular diagnoses (p ≤ 0.002). Among non-dialysis participants, DBP was lower in FSGS versus other diagnoses (FSGS-dialysis interaction p = 0.02). Winter season, older age, FSGS and GN, and higher FGF23 concentrations were independently associated with lower concentrations of free and bioavailable 25(OH)D. Black race was associated with lower total 25(OH)D and DBP, but not free or bioavailable 25(OH)D. 24,25(OH)(2)D was the vitamin D metabolite most strongly associated with iPTH. Lower 25(OH)D and higher iPTH concentrations, black race, and greater CKD severity were independently associated with lower levels of 24,25(OH)(2)D, while higher FGF23 concentrations and GN were associated with higher levels of 24,25(OH)(2)D.Children with CKD exhibit altered catabolism and concentrations of DBP and free and bioavailable 25(OH)D, and there is an important impact of their underlying disease.

View details for DOI 10.1007/s00467-013-2493-9

View details for Web of Science ID 000322323700017

View details for PubMedID 23728936
Long-Term Inflammation and Glucocorticoid Therapy Impair Skeletal Modeling During Growth in Childhood Crohn Disease JOURNAL OF CLINICAL ENDOCRINOLOGY & METABOLISM Tsampalieros, A., Lam, C. K., Spencer, J. C., Thayu, M., Shults, J., Zemel, B. S., Herskovitz, R. M., Baldassano, R. N., Leonard, M. B. 2013; 98 (8): 3438-3445
Abstract

Glucocorticoids and inflammation inhibit bone formation; however, the impact on skeletal modeling is unknown.The objectives of the study were to examine changes in bone mineral density (BMD) and cortical structure after Crohn disease (CD) diagnosis and identify associations with growth, glucocorticoids, and disease activity.This was a prospective cohort study among 76 CD participants, aged 5-21 years. Tibia quantitative computed tomography trabecular BMD and cortical dimensions were obtained at diagnosis and 6 and 12 and a median of 42 months later; 51 completed the final visit.Sex, race, and age-specific Z-scores were generated for outcomes based on more than 650 reference participants, and cortical dimension Z-scores were further adjusted for tibia length. Generalized estimating equations were used to model changes in Z-scores.Disease activity improved over the study interval (P < .001). Trabecular BMD Z-scores improved over the first 6 months; increases were associated with improved disease activity (P < .001), younger age (P = .005), and increases in vitamin D levels (P = .02). Greater increases in tibia length were associated with greater increases in cortical area Z-scores (P < .001). Greater glucocorticoid doses and disease activity were significantly associated with failure to accrue cortical area and were more pronounced with greater linear growth (interaction P < .05). Mean (±SD) trabecular BMD (-1.0 ± 1.21) and cortical area (-0.57 ± 1.10) Z-scores at the final visit were significantly reduced.CD was associated with persistent deficits in trabecular BMD, although younger participants demonstrated a greater potential for recovery. In addition, greater linear growth was associated with a greater recovery of cortical dimensions, especially among participants with less glucocorticoid exposure and inflammation. These data suggest that younger age and concurrent growth provide a window of opportunity for skeletal recovery.

View details for DOI 10.1210/jc.2013-1631

View details for Web of Science ID 000322781300063

View details for PubMedID 23690309
FGF23 Modifies the Relationship Between Vitamin D and Cardiac Remodeling CIRCULATION-HEART FAILURE Ky, B., Shults, J., Keane, M. G., Sutton, M. S., Wolf, M., Feldman, H. I., Reese, P. P., Anderson, C. A., Townsend, R. R., Deo, R., Lo, J., Gadegbeku, C., Carlow, D., Sulik, M. J., Leonard, M. B. 2013; 6 (4): 817-824
Abstract

There is growing evidence to support an important role for vitamin D and related hormones, parathyroid hormone and fibroblast growth factor 23 (FGF23), on cardiac remodeling in chronic kidney disease. Our objective was to determine the relationships between vitamin D and cardiac remodeling in chronic kidney disease and the effects of parathyroid hormone and FGF23 on these associations.In 1431 participants from the Chronic Renal Insufficiency Cohort study, we measured 25-hydroxyvitamin D (25(OH)D), 1,25-dihydroxyvitamin D (1,25(OH)2D), FGF23, and parathyroid hormone and performed quantitative echocardiography. Using linear regression methods, we determined significant negative interactions between 25(OH)D and FGF23 on left ventricular (LV) mass (P=0.016), end-diastolic volume (P=0.029), and end-systolic volumes (P=0.021). In participants with an FGF23 level greater than the median of 123.5 RU/mL, each doubling of 25(OH)D was associated with a 2.5% (95% confidence interval, -4.8, -0.2) lower LV mass. This association was less pronounced with FGF23 levels less than the median (0.4%; 95% confidence interval, -1.9, 2.7). Conversely, in participants with deficient 25(OH)D levels <20 ng/mL, each doubling of FGF23 was associated with a 3.4% (95% confidence interval, 1.2, 5.6) greater LV mass compared with only a 1.6% (95% confidence interval, -0.2, 3.5) difference in participants with sufficient 25(OH)D. Similar findings were observed with 25(OH)D and volumes (P<0.05), and 1,25(OH)2D and LV mass and volumes (P<0.005). There was no effect modification by parathyroid hormone.We identified significant interactions among 25(OH)D, 1,25(OH)2D, and FGF23 on cardiac remodeling. Increased LV mass and cavity dilatation were observed with low 25(OH)D and high FGF23. Our findings suggest that consideration of both hormones is crucial to understanding the role of either in cardiac remodeling, and may have important therapeutic implications.

View details for DOI 10.1161/CIRCHEARTFAILURE.112.000105

View details for Web of Science ID 000335157800032

View details for PubMedID 23748358
Fat and lean BMI reference curves in children and adolescents and their utility in identifying excess adiposity compared with BMI and percentage body fat AMERICAN JOURNAL OF CLINICAL NUTRITION Weber, D. R., Moore, R. H., Leonard, M. B., Zemel, B. S. 2013; 98 (1): 49-56
Abstract

Body mass index (BMI) and percentage body fat (%BF) are widely used to assess adiposity. These indexes fail to account for independent contributions of fat mass (FM) and lean body mass (LBM) to body weight, which vary according to age, sex, pubertal status, and population ancestry in the pediatric population.The objective was to develop pediatric reference curves for fat mass index (FMI) and lean body mass index (LBMI) and evaluate the effects of population ancestry and LBM on measures of excess adiposity (BMI, %BF, and FMI).Sex-specific FMI and LBMI reference curves relative to age for children and adolescents aged 8-20 y were generated from cross-sectional body-composition data measured by dual-energy X-ray absorptiometry from NHANES.The mean LBMI z score was higher in blacks (males: 0.26; females: 0.45) than in whites (males: -0.07; females: -0.09) and Mexican Americans (males: 0.05; females: -0.09). The positive predictive value of overweight by BMI to identify excess adiposity defined by FMI was lower in blacks (males: 35.9%; females: 30.3%) than in whites (males: 65.4%; females: 52.2%) and Mexican Americans (males: 73.3%; females: 68.3%). Participants classified as having excess adiposity by FMI but normal adiposity by %BF had significantly higher BMI, LBMI, and height z scores than did those classified as having excess adiposity by %BF but normal adiposity by FMI.Relative to FMI, the prevalence of excess adiposity is overestimated by BMI in blacks and underestimated by %BF in individuals with high LBM. The use of FMI and LBMI improves on the use of %BF and BMI by allowing for the independent assessment of FM and LBM.

View details for DOI 10.3945/ajcn.112.053611

View details for Web of Science ID 000320909200008

View details for PubMedID 23697708
Mineral Metabolism and Cortical Volumetric Bone Mineral Density in Childhood Chronic Kidney Disease JOURNAL OF CLINICAL ENDOCRINOLOGY & METABOLISM Denburg, M. R., Tsampalieros, A. K., de Boer, I. H., Shults, J., Kalkwarf, H. J., Zemel, B. S., Foerster, D., Stokes, D., Leonard, M. B. 2013; 98 (5): 1930-1938
Abstract

The relationships among cortical volumetric bone mineral density (CortBMD) and comprehensive measures of mineral metabolism have not been addressed in chronic kidney disease (CKD).The aim of the study was to identify the determinants of CortBMD in childhood CKD. A secondary objective was to assess whether CortBMD was associated with subsequent fracture.This prospective cohort study included 171 children, adolescents, and young adults (aged 5-21 years) with CKD stages 2-5D at enrollment and 89 1 year later.Serum measures included vitamin D [25-hydroxyvitamin D (25[OH]D), 1,25-dihydroxyvitamin D (1,25(OH)₂D), 24,25-dihydroxyvitamin D], vitamin D-binding protein, intact PTH, fibroblast growth factor 23, calcium, and phosphorus. Tibia quantitative computed tomography measures of CortBMD were expressed as sex-, race-, and age-specific Z-scores based on 675 controls. Multivariable linear regression identified the independent correlates of CortBMD Z-scores and the change in CortBMD Z-scores.Lower calcium (β = .31/1 mg/dL, P = .01) and 25(OH)D (β = .18/10 ng/mL, P = .04) and higher PTH (β = -.02/10%, P = .002) and 1,25(OH)₂D (β = -.07/10%, P < .001) were independently associated with lower CortBMD Z-scores at baseline. The correlations of total, free, and bioavailable 25(OH)D with CortBMD did not differ. Higher baseline 1,25(OH)₂D (P < .05) and greater increases in PTH (P < .001) were associated with greater declines in CortBMD Z-scores. Greater increases in calcium concentrations were associated with greater increases in CortBMD Z-scores in growing children (interaction P = .009). The hazard ratio for fracture was 1.75 (95% confidence interval 1.15-2.67; P = .009) per SD lower baseline CortBMD.Greater PTH and 1,25(OH)₂D and lower calcium concentrations were independently associated with baseline and progressive cortical deficits in childhood CKD. Lower CortBMD Z-score was associated with increased fracture risk.

View details for DOI 10.1210/jc.2012-4188

View details for Web of Science ID 000318688200053

View details for PubMedID 23547048
Changes in bone structure and the muscle-bone unit in children with chronic kidney disease KIDNEY INTERNATIONAL Tsampalieros, A., Kalkwarf, H. J., Wetzsteon, R. J., Shults, J., Zemel, B. S., Foster, B. J., Foerster, D. L., Leonard, M. B. 2013; 83 (3): 495-502
Abstract

The impact of pediatric chronic kidney disease (CKD) on acquisition of volumetric bone mineral density (BMD) and cortical dimensions is lacking. To address this issue, we obtained tibia quantitative computed tomography scans from 103 patients aged 5-21 years with CKD (26 on dialysis) at baseline and 12 months later. Gender, ethnicity, tibia length, and/or age-specific Z-scores were generated for trabecular and cortical BMD, cortical area, periosteal and endosteal circumference, and muscle area based on over 700 reference subjects. Muscle area, cortical area, and periosteal and endosteal Z-scores were significantly lower at baseline compared with the reference cohort. Cortical BMD, cortical area, and periosteal Z-scores all exhibited a significant further decrease over 12 months. Higher parathyroid hormone levels were associated with significantly greater increases in trabecular BMD and decreases in cortical BMD in the younger patients (significant interaction terms for trabecular BMD and cortical BMD). The estimated glomerular filtration rate was not associated with changes in BMD Z-scores independent of parathyroid hormone. Changes in muscle and cortical area were significantly and positively associated in control subjects but not in CKD patients. Thus, children and adolescents with CKD have progressive cortical bone deficits related to secondary hyperparathyroidism and potential impairment of the functional muscle-bone unit. Interventions are needed to enhance bone accrual in childhood-onset CKD.

View details for DOI 10.1038/ki.2012.347

View details for Web of Science ID 000316156100022

View details for PubMedID 23032560
Glucocorticoid effects on changes in bone mineral density and cortical structure in childhood nephrotic syndrome JOURNAL OF BONE AND MINERAL RESEARCH Tsampalieros, A., Gupta, P., Denburg, M. R., Shults, J., Zemel, B. S., Mostoufi-Moab, S., Wetzsteon, R. J., Herskovitz, R. M., Whitehead, K. M., Leonard, M. B. 2013; 28 (3): 480-488
Abstract

The impact of glucocorticoids (GC) on skeletal development has not been established. The objective of this study was to examine changes in volumetric bone mineral density (vBMD) and cortical structure over 1 year in childhood nephrotic syndrome (NS) and to identify associations with concurrent GC exposure and growth. Fifty-six NS participants, aged 5 to 21 years, were enrolled a median of 4.3 (0.5 to 8.1) years after diagnosis. Tibia peripheral quantitative computed tomography (pQCT) scans were obtained at enrollment and 6 and 12 months later. Sex, race, and age-specific Z-scores were generated for trabecular vBMD (TrabBMD-Z), cortical vBMD (CortBMD-Z), and cortical area (CortArea-Z) based on >650 reference participants. CortArea-Z was further adjusted for tibia length-for-age Z-score. Quasi-least squares regression was used to identify determinants of changes in pQCT Z-scores. At enrollment, mean TrabBMD-Z (-0.54 ± 1.32) was significantly lower (p = 0.0001) and CortBMD-Z (0.73 ± 1.16, p < 0.0001) and CortArea-Z (0.27 ± 0.91, p = 0.03) significantly greater in NS versus reference participants, as previously described. Forty-eight (86%) participants were treated with GC over the study interval (median dose 0.29 mg/kg/day). On average, TrabBMD-Z and CortBMD-Z did not change significantly over the study interval; however, CortArea-Z decreased (p = 0.003). Greater GC dose (p < 0.001), lesser increases in tibia length (p < 0.001), and lesser increases in CortArea-Z (p = 0.003) were independently associated with greater increases in CortBMD-Z. Greater increases in tibia length were associated with greater declines in CortArea-Z (p < 0.01); this association was absent in reference participants (interaction p < 0.02). In conclusion, GC therapy was associated with increases in CortBMD-Z, potentially related to suppressed bone formation and greater secondary mineralization. Conversely, greater growth and expansion of CortArea-Z (ie, new bone formation) were associated with declines in CortBMD-Z. Greater linear growth was associated with impaired expansion of cortical area in NS. Studies are needed to determine the fracture implications of these findings.

View details for DOI 10.1002/jbmr.1785

View details for Web of Science ID 000315106300008

View details for PubMedID 23044926
Associations between body composition and bone density and structure in men and women across the adult age spectrum BONE Baker, J. F., Davis, M., Alexander, R., Zemel, B. S., Mostoufi-Moab, S., Shults, J., Sulik, M., Schiferl, D. J., Leonard, M. B. 2013; 53 (1): 34-41
Abstract

The objective of this study was to identify independent associations between body composition and bone outcomes, including cortical structure and cortical and trabecular volumetric bone mineral density (vBMD) across the adult age spectrum.This cross-sectional study evaluated over 400 healthy adults (48% male, 44% black race), ages 21-78years. Multivariable linear regression models evaluated associations between whole-body DXA measures of lean body mass index (LBMI) and fat mass index (FMI) and tibia peripheral quantitative CT (pQCT) measures of cortical section modulus, cortical and trabecular vBMD and muscle density (as a measure of intramuscular fat), adjusted for age, sex, and race. All associations reported below were statistically significant (p<0.05).Older age and female sex were associated with lower LBMI and muscle strength. Black race was associated with greater LBMI but lower muscle density. Greater FMI was associated with lower muscle density. Cortical section modulus was positively associated with LBMI and muscle strength and negatively associated with FMI. Adjustment for body composition eliminated the greater section modulus observed in black participants and attenuated the lower section modulus in females. Greater LBMI was associated with lower cortical BMD and greater trabecular BMD. FMI was not associated with either BMD outcome. Greater muscle density was associated with greater trabecular and cortical BMD. Associations between body composition and bone outcomes did not vary by sex (no significant tests for interaction).These data highlight age-, sex- and race-specific differences in body composition, muscle strength and muscle density, and demonstrate discrete associations with bone density and structure. These data also show that age-, sex- and race-related patterns of bone density and strength are independent of differences in body composition. Longitudinal studies are needed to examine the temporal relations between changes in bone and body composition.

View details for DOI 10.1016/j.bone.2012.11.035

View details for Web of Science ID 000314257100007

View details for PubMedID 23238122

View details for PubMedCentralID PMC3552077
Nutritional vitamin D use in chronic kidney disease: a survey of pediatric nephrologists PEDIATRIC NEPHROLOGY Griffin, L. M., Denburg, M. R., Shults, J., Furth, S. L., Salusky, I. B., Hwang, W., Leonard, M. B. 2013; 28 (2): 265-275
Abstract

Vitamin D deficiency may contribute to risk of cardiovascular disease, diabetes, and infections, in addition to known effects on mineral metabolism. Controversy remains regarding the use of nutritional vitamin D supplementation in chronic kidney disease (CKD), and the supplementation practices of pediatric nephrologists are unknown.An electronic survey containing eight vignettes was sent to physician members of the International Pediatric Nephrology Association in 2011 to identify physician and patient characteristics that influence nephrologists to supplement CKD patients with nutritional vitamin D. Vignettes contained patient characteristics including light vs dark skin, CKD stage, cause of renal disease, parathyroid hormone (PTH), and 25(OH) vitamin D levels. Multivariate logistic generalized estimating equation regression was used to identify predictors of supplementation.Of 1,084 eligible physicians, 504 (46%) completed the survey. Supplementation was recommended in 73% of cases overall (ranging from 91% of those with vitamin D levels <10 ng/mL to 35% with levels >30). Greater CKD severity was associated with greater recommendation of supplementation, especially for patients with higher vitamin D levels (test for interaction p < 0.0001). PTH level above target for CKD stage was associated with greater recommendation to supplement in pre-dialysis CKD, but did not have an impact on recommendations in dialysis patients (test for interaction p < 0.0001). Skin color, cause of CKD, and albumin levels were not associated with supplementation recommendation.Recommending nutritional vitamin D is common worldwide, driven by CKD stage and vitamin D and PTH levels. Future studies are needed to establish the risks and benefits of supplementation.

View details for DOI 10.1007/s00467-012-2307-5

View details for Web of Science ID 000313431600012

View details for PubMedID 23086591
Physical Performance and Frailty in Chronic Kidney Disease AMERICAN JOURNAL OF NEPHROLOGY Reese, P. P., Cappola, A. R., Shults, J., Townsend, R. R., Gadegbeku, C. A., Anderson, C., Baker, J. F., Carlow, D., Sulik, M. J., Lo, J. C., Go, A. S., Ky, B., Mariani, L., Feldman, H. I., Leonard, M. B. 2013; 38 (4): 307-315
Abstract

Poor physical performance and frailty are associated with elevated risks of death and disability. Chronic kidney disease (CKD) is also strongly associated with these outcomes. The risks of poor physical performance and frailty among CKD patients, however, are not well established.We measured the Short Physical Performance Battery (SPPB; a summary test of gait speed, chair raises and balance; range 0-12) and the five elements of frailty among 1,111 Chronic Renal Insufficiency Cohort participants. Adjusting for demographics and multiple comorbidities, we fit a linear regression model for the outcome of SPPB score and an ordinal logistic regression model for frailty status.Median (interquartile range, IQR) age was 65 (57-71) years, median estimated glomerular filtration rate (eGFR) for non-dialysis patients was 49 (36-62) ml/min/1.73 m(2), and median SPPB score was 9 (7-10). Seven percent of participants were frail and 43% were pre-frail. Compared with the SPPB score for eGFR >60 ml/min/1.73 m(2), the SPPB was 0.51 points lower for eGFR 30-59; 0.61 points lower for eGFR 15-29, and 1.75 points lower for eGFR <15 (p < 0.01 for all comparisons). eGFR 30-59 (odds ratio, OR 1.45; p = 0.024), eGFR 15-29 (OR 2.02; p = 0.002) and eGFR <15 (OR 4.83; p < 0.001) were associated with worse frailty status compared with eGFR >60 ml/min/1.73 m(2).CKD severity was associated with poor physical performance and frailty in a graded fashion. Future trials should determine if outcomes for CKD patients with frailty and poor physical performance are improved by targeted interventions.

View details for DOI 10.1159/000355568

View details for Web of Science ID 000326134100006

View details for PubMedID 24107579

View details for PubMedCentralID PMC4019506
Changes in Vitamin D and Parathyroid Hormone Metabolism in Incident Pediatric Crohn's Disease INFLAMMATORY BOWEL DISEASES Prosnitz, A. R., Leonard, M. B., Shults, J., Zemel, B. S., Hollis, B. W., Denson, L. A., Baldassano, R. N., Cohen, A. B., Thayu, M. 2013; 19 (1): 45-53
Abstract

Prior studies of vitamin D metabolism in Crohn's disease (CD) did not include controls or examine changes following diagnosis. This study examined associations among 25-hydroxyvitamin D [25(OH)D], 1,25-dihydroxyvitamin D [1,25(OH)(2)D], and parathyroid hormone (PTH) levels in incident pediatric CD, compared with controls, and following diagnosis.Serum vitamin D and PTH were measured at diagnosis (n = 78), 6, 12, and a median of 43 months (n = 52) later in CD participants, and once in 221 controls. Multivariate regression was used to examine baseline associations and quasi-least squares regression to assess subsequent changes.At diagnosis, 42% of CD participants were 25(OH)D-deficient (<20 ng/mL). The odds ratio for deficiency was 2.1 (95% confidence interval [CI]: 1.1, 3.9; P < 0.05) vs. controls, adjusted for age, race, and season. 1,25(OH)(2)D was lower in CD vs. controls (P < 0.05), adjusted for 25(OH)D, tumor necrosis factor alpha (TNF-α), and PTH. TNF-α was associated with lower 1,25(OH)(2)D (P < 0.05), and the positive association between PTH and 1,25(OH)(2)D in controls was absent in CD (interaction P = 0.02). Among participants with 25(OH)D <30 ng/mL, CD was associated with lower PTH (P < 0.05) vs. controls. Following diagnosis, 25(OH)D and 1,25(OH)(2)D improved (P < 0.001). At the final visit, 3% were 25(OH)D-deficient, PTH was no longer low relative to 25(OH)D, and 1,25(OH)(2)D was significantly elevated (P < 0.001) compared with controls.Incident CD was associated with 25(OH)D and 1,25(OH)2D deficiency and a relative hypoparathyroidism that resolved following diagnosis. Inflammatory cytokine suppression of PTH and renal 1-α-hyroxylase may contribute to these alterations.

View details for DOI 10.1002/ibd.22969

View details for Web of Science ID 000316397200014

View details for PubMedID 22488969
Risk of hip fracture associated with hepatitis c virus infection and hepatitis C/human immunodeficiency virus coinfection HEPATOLOGY Lo Re, V., Volk, J., Newcomb, C. W., Yang, Y., Freeman, C. P., Hennessy, S., Kostman, J. R., Tebas, P., Leonard, M. B., Localio, A. R. 2012; 56 (5): 1688-1698
Abstract

Hepatitis C virus (HCV) infection has been associated with reduced bone mineral density, but its association with fracture rates is unknown, particularly in the setting of human immunodeficiency virus (HIV) coinfection. Our aims were to determine whether persons with HCV infection alone are at increased risk for hip fracture, compared to uninfected individuals, and to examine whether the risk of hip fracture is higher among HCV/HIV-coinfected persons, compared to those with HCV alone, those with HIV alone, and those uninfected with either virus. We conducted a cohort study in 36,950 HCV/HIV-coinfected, 276,901 HCV-monoinfected, 95,827 HIV-monoinfected, and 3,110,904 HCV/HIV-uninfected persons within the U.S. Medicaid populations of California, Florida, New York, Ohio, and Pennsylvania (1999-2005). Incidence rates of hip fracture were lowest among uninfected persons (1.29 events/1,000 person-years), increased with the presence of either HIV infection (1.95 events/1,000 person-years) or HCV infection (2.69 events/1,000 person-years), and were highest among HCV/HIV-coinfected individuals (3.06 events/1,000 person-years). HCV/HIV coinfection was associated with an increased relative hazard (adjusted hazard ratio [HR] [95% confidence interval; CI]) of hip fracture, compared to HCV-monoinfected (HR, 1.38; 95% CI: 1.25-1.53), HIV-monoinfected (females: HR, 1.76; 95% CI: 1.44-2.16; males: HR, 1.36; 95% CI: 1.20-1.55), and HCV/HIV-uninfected persons (females: HR, 2.65; 95% CI: 2.21-3.17; males: HR, 2.20; 95% CI: 1.97-2.47). HCV monoinfection was associated with an increased risk of hip fracture, compared to uninfected individuals, and the relative increase was highest in the youngest age groups (females, 18-39 years: HR, 3.56; 95% CI: 2.93-4.32; males, 18-39 years: HR, 2.40; 95% CI: 2.02-2.84).Among Medicaid enrollees, HCV/HIV coinfection was associated with increased rates of hip fracture, compared to HCV-monoinfected, HIV-monoinfected, and HCV/HIV-uninfected persons. HCV-monoinfected patients had an increased risk of hip fracture, compared to uninfected individuals.

View details for DOI 10.1002/hep.25866

View details for Web of Science ID 000310543100014

View details for PubMedID 22619086
Body composition analysis in the pediatric population. Pediatric endocrinology reviews : PER Weber, D. R., Leonard, M. B., Zemel, B. S. 2012; 10 (1): 130-139
Abstract

Body composition analysis has become a useful tool in both clinical and research settings. Its use in the pediatric population is complicated by the rapid periods of growth and physical development that are characteristic of infancy, childhood, and adolescence. A thorough understanding of the changing nature of body composition during this time is essential for choosing the most appropriate measurement technique for a given individual, population, or clinical question. Growing evidence suggests that tissues such as fat, muscle, and bone are intimately involved in the regulation of whole body energy metabolism. This knowledge, when coupled with advancements in imaging techniques such as MRI and PET-CT, offers the possibility of developing new models of "functional" body composition. These models may prove to be especially important when assessing malnutrition and metabolic risk in patients with chronic disease.

View details for PubMedID 23469390
Vitamin D, Metabolic Dyslipidemia, and Metabolic Syndrome in Rheumatoid Arthritis AMERICAN JOURNAL OF MEDICINE Baker, J. F., Mehta, N. N., Baker, D. G., Toedter, G., Shults, J., Von Feldt, J. M., Leonard, M. B. 2012; 125 (10)
Abstract

Vitamin D deficiency is a potential risk factor for cardiometabolic disease. We investigated the associations between vitamin D and dyslipidemia and the metabolic syndrome in patients with rheumatoid arthritis, a group at high risk for cardiovascular disease.Serum 25(OH)vitamin D and lipoprotein levels were measured at baseline in a random sample of 499 participants, ages 18-85 years, enrolled in a randomized trial of golimumab (GOlimumab Before Employing methotrexate as the First-line Option in the treatment of Rheumatoid arthritis of Early onset or GO-BEFORE Trial). Participants had rheumatoid arthritis with active disease, and were naïve to methotrexate and biologic therapies. Multivariable linear regression was performed to assess associations between vitamin D levels and lipoprotein fractions. Multivariable logistic regression was performed to determine the odds of hyperlipidemia and the metabolic syndrome in participants with vitamin D deficiency (<20 ng/mL).In multivariable linear regression, vitamin D levels (per 10 ng/mL) were associated inversely with low-density lipoprotein (β: -0.029 [-0.049, -0.0091], P=.004) and triglyceride (β: -0.094 [-0.15, -0.039] P=.001) levels, adjusted for demographic, cardiovascular, and disease-specific variables. Vitamin D and high-density lipoprotein levels were not associated in univariate or multivariate analyses. Vitamin D deficiency was associated independently with an increased odds of hyperlipidemia (odds ratio 1.72; 95% confidence interval, 1.10-2.45; P=.014) and metabolic syndrome (odds ratio 3.45; 95% confidence interval, 1.75-6.80; P <.001) in adjusted models.In conclusion, vitamin D deficiency was associated with the metabolic syndrome and dyslipidemia in rheumatoid arthritis, suggesting a potential role in cardiovascular disease risk. Large-scale, prospective studies are needed to determine if vitamin D supplementation improves lipoprotein levels and reduces cardiovascular risk in rheumatoid arthritis.

View details for DOI 10.1016/j.amjmed.2012.01.025

View details for Web of Science ID 000309120400036

View details for PubMedID 22800875
Longitudinal Assessment of Bone Density and Structure in Childhood Survivors of Acute Lymphoblastic Leukemia without Cranial Radiation JOURNAL OF CLINICAL ENDOCRINOLOGY & METABOLISM Mostoufi-Moab, S., Brodsky, J., Isaacoff, E. J., Tsampalieros, A., Ginsberg, J. P., Zemel, B., Shults, J., Leonard, M. B. 2012; 97 (10): 3584-3592
Abstract

Children with acute lymphoblastic leukemia (ALL) are at risk for impaired bone accrual. This peripheral quantitative computed tomography study assessed changes in bone mineral density (BMD) and structure after completion of ALL treatment.Fifty ALL participants, ages 5-22 yr, were enrolled within 2 yr (median 0.8 yr) after completing ALL therapy. Tibia peripheral quantitative computed tomography scans were performed at enrollment and 12 months later. Age-, sex-, and race-specific Z-scores for trabecular BMD (TrabBMD), cortical BMD (CortBMD), and cortical area (CortArea) were generated based on more than 650 reference participants. Multivariable linear regression models examined determinants of changes in Z-scores.At enrollment, mean TrabBMD (-1.03±1.34) and CortBMD (-0.84±1.05) Z-scores were low (both P<0.001) compared with reference participants. TrabBMD and CortBMD Z-scores increased to -0.58±1.41 and -0.51±0.91 over 1 yr, respectively (both P<0.001). Changes in cortical outcomes varied according to the interval since completion of therapy. Among those enrolled less than 6 months after therapy, CortArea Z-scores increased and CortBMD Z-scores decreased (both P<0.01). Among those enrolled 6 months or more after therapy, CortArea Z-scores did not change and CortBMD Z-scores increased (P<0.01). Changes in CortArea and CortBMD Z-scores were inversely associated (r=-0.32, P<0.001). Cumulative glucocorticoid exposure, leukemia risk status, and antimetabolite chemotherapy were not associated with outcomes.TrabBMD was low after completion of ALL therapy and improved significantly. Early increases in cortical dimensions were associated with declines in CortBMD; however, participants further from ALL therapy demonstrated stable cortical dimensions and increases in CortBMD, potentially reflecting the time necessary to mineralize newly formed bone.

View details for DOI 10.1210/jc.2012-2393

View details for Web of Science ID 000309664400054

View details for PubMedID 22865901
Associations between vitamin D, disease activity, and clinical response to therapy in rheumatoid arthritis CLINICAL AND EXPERIMENTAL RHEUMATOLOGY Baker, J. F., Baker, D. G., TOEDTER, G., Shults, J., Von Feldt, J. M., Leonard, M. B. 2012; 30 (5): 658-664
Abstract

Vitamin D deficiency is a potential risk factor for autoimmunity. Prior studies of the association between vitamin D levels and rheumatoid arthritis (RA) disease activity have yielded conflicting results.Serum 25(OH)vitamin D levels were measured at baseline in 499 participants with active RA, ages 18-85 years, enrolled in a randomised clinical trial of golimumab (Go-Before Trial). Subjects were methotrexate and biologic therapy naïve. Multivariable linear regression was used to assess associations between vitamin D levels and disease activity scores (DAS28), van der Heijde-Sharp (vdHS) erosion scores, and serum inflammatory markers. Generalised estimating equations were used to evaluate the associations between vitamin D status and the response to therapy over 52 weeks, using the DAS28 and ACR response.Forty-eight percent of participants were vitamin D deficient, defined as serum 25(OH)vitamin D <20 ng/mL. Deficiency was not associated with greater DAS28 (β-0.021 [95% CI -0.22, 0.18]), adjusted for age, race, sex, BMI, disease duration and glomerular filtration rate. Vitamin D deficiency was not associated with baseline vdHS scores or inflammatory markers in adjusted or unadjusted models. There was no association between baseline vitamin D deficiency and change in DAS28 (β = -0.024 [-0.30, 0.25]), proportion meeting ACR response (OR 0.82 [0.56, 1.20]), or radiographic progression at 52 weeks (OR 0.91 [0.59-1.40]).Vitamin D levels were not associated with RA disease activity, inflammatory markers, or vdHS scores at baseline. Furthermore, there was no association between baseline vitamin D level and response to therapy or radiographic progression.

View details for Web of Science ID 000310828600003

View details for PubMedID 22776409
Estimating GFR Among Participants in the Chronic Renal Insufficiency Cohort (CRIC) Study AMERICAN JOURNAL OF KIDNEY DISEASES Anderson, A. H., Yang, W., Hsu, C., Joffe, M. M., Leonard, M. B., Xie, D., Chen, J., Greene, T., Jaar, B. G., Kao, P., Kusek, J. W., Landis, J. R., Lash, J. P., Townsend, R. R., Weir, M. R., Feldman, H. I. 2012; 60 (2): 250-261
Abstract

Glomerular filtration rate (GFR) is considered the best measure of kidney function, but repeated assessment is not feasible in most research studies.Cross-sectional study of 1,433 participants in the Chronic Renal Insufficiency Cohort (CRIC) Study (ie, the GFR subcohort) to derive an internal GFR estimating equation using a split-sample approach.Adults from 7 US metropolitan areas with mild to moderate chronic kidney disease; 48% had diabetes and 37% were black.CRIC GFR estimating equation.Urinary (125)I-iothalamate clearance testing (measured GFR [mGFR]).Laboratory measures, including serum creatinine and cystatin C, and anthropometrics.In the validation data set, the model that included serum creatinine level, serum cystatin C level, age, sex, and race was the most parsimonious and similarly predictive of mGFR compared with a model additionally including bioelectrical impedance analysis phase angle, CRIC clinical center, and 24-hour urinary creatinine excretion. Specifically, root mean square errors for the separate models were 0.207 versus 0.202, respectively. Performance of the CRIC GFR estimating equation was most accurate for the subgroups of younger participants, men, nonblacks, non-Hispanics, those without diabetes, those with body mass index <30 kg/m(2), those with higher 24-hour urine creatinine excretion, those with lower high-sensitivity C-reactive protein levels, and those with higher mGFRs.Urinary clearance of (125)I-iothalamate is an imperfect measure of true GFR; cystatin C level is not standardized to certified reference material; lack of external validation; small sample sizes limit analyses of subgroup-specific predictors.The CRIC GFR estimating equation predicts mGFR accurately in the CRIC cohort using serum creatinine and cystatin C levels, age, sex, and race. Its performance was best in younger and healthier participants.

View details for DOI 10.1053/j.ajkd.2012.04.012

View details for Web of Science ID 000306477200013

View details for PubMedID 22658574
Assessment of dual-energy x-ray absorptiometry measures of bone health in pediatric chronic kidney disease PEDIATRIC NEPHROLOGY Griffin, L. M., Kalkwarf, H. J., Zemel, B. S., Shults, J., Wetzsteon, R. J., Strife, C. F., Leonard, M. B. 2012; 27 (7): 1139-1148
Abstract

Dual-energy X-ray absorptiometry (DXA) techniques are limited in childhood chronic kidney disease (CKD) by the confounding effect of short stature and opposing parathyroid hormone effects on trabecular and cortical bone. Peripheral quantitative computed tomography (pQCT) is not subject to these limitations.Lumbar spine (LS) and whole-body (WB) DXA and tibia pQCT scans were obtained in 88 stage 4-5 CKD and >650 healthy participants, ages 5-21 years. Sex- and race-specific Z-scores were generated for bone mineral density (BMD) and bone mineral content (BMC) by DXA, relative to age and adjusted for height Z-score (LS-BMD-Z and WB-BMC-Z), and compared to pQCT Z-scores for trabecular BMD (TrabBMD-Z) for age and cortical BMC (CortBMC-Z) for age and tibia length.LS-BMD-Z [0.50 (95% C.I. 0.28, 0.73), p<0.0001] and TrabBMD-Z [0.53 (0.27, 0.79), p<0.0001] were greater in CKD, and WB-BMC-Z [-0.36 (-0.53, -0.19), p<0.0001] and CortBMC-Z [-0.48 (-0.70, -0.27), p<0.0001] were lower, compared to reference participants. Z-scores were correlated at trabecular (LS-BMD-Z and TrabBMD-Z: R=0.36) and cortical (WB-BMC-Z and CortBMC-Z: R=0.64) sites in CKD; similar to correlations in reference participants.Lumbar spine and whole-body DXA suggested greater trabecular BMD and lower cortical BMC in CKD, consistent with pQCT results; however, correlations were modest. Studies are needed to identify methods that predict fracture in childhood CKD.

View details for DOI 10.1007/s00467-012-2116-x

View details for Web of Science ID 000304626700014

View details for PubMedID 22350304
Fibroblast Growth Factor 23 and Inflammation in CKD CLINICAL JOURNAL OF THE AMERICAN SOCIETY OF NEPHROLOGY Mendoza, F. A., Lsakova, T., Ricardo, A. C., Xie, H., Navaneethan, S. D., Anderson, A. H., Bazzano, L. A., Xie, D., Kretzler, M., Nesse, L., Hamm, L. L., Negrea, L., Leonard, M. B., Raj, D., Wolf, M. 2012; 7 (7): 1155-1162
Abstract

Levels of fibroblast growth factor 23 (FGF23) and inflammatory markers are commonly elevated in CKD, and each is associated with adverse clinical outcomes. This study tested the hypothesis that FGF23 is independently associated with inflammation in CKD.The association between levels of FGF23 and the inflammatory markers IL-6, C-reactive protein (CRP), TNF-α, and fibrinogen was assessed in a cross-sectional analysis of 3879 participants enrolled in the Chronic Renal Insufficiency Cohort (CRIC) study between June 2003 and September 2008.FGF23 correlated directly with IL-6 (r=0.4), CRP (r=0.2), TNF-α (r=0.4), and fibrinogen (r=0.3; P<0.001 for each). In univariate and multivariable-adjusted linear regression analyses, natural log (ln) transformed FGF23 was significantly associated with lnIL-6, lnCRP, lnTNF-α, and fibrinogen (P<0.001 for each). Each unit higher lnFGF23 was associated with severe inflammation, defined as levels of all inflammatory markers in the highest 25th percentile, in univariate (odds ratio [OR], 2.4 [95% confidence interval (CI), 2.0-2.9]) and multivariable-adjusted (OR, 2.0 [95% CI, 1.6-2.5]) logistic regression analyses. Ascending FGF23 quartiles were independently associated with severe inflammation (OR, 5.6 for the highest versus lowest FGF23 quartile [95% CI, 2.3-13.9]; P for trend < 0.001).Higher FGF23 levels are independently associated with higher levels of inflammatory markers in patients with CKD and with significantly greater odds of severe inflammation. Future studies should evaluate whether inflammation modifies the association between FGF23 and adverse outcomes in CKD.

View details for DOI 10.2215/CJN.13281211

View details for Web of Science ID 000306148500015

View details for PubMedID 22554719
Earlier Onset and Greater Severity of Disordered Mineral Metabolism in Diabetic Patients With Chronic Kidney Disease DIABETES CARE Wahl, P., Xie, H., Scialla, J., Anderson, C. A., Bellovich, K., Brecklin, C., Chen, J., Feldman, H., Gutierrez, O. M., Lash, J., Leonard, M. B., Negrea, L., Rosas, S. E., Anderson, A. H., Townsend, R. R., Wolf, M., Isakova, T. 2012; 35 (5): 994-1001
Abstract

Disordered mineral metabolism is a common complication of chronic kidney disease (CKD) and a novel risk factor for CKD progression, cardiovascular disease, and mortality. Although diabetes is the leading cause of CKD and is associated with worse clinical outcomes than other etiologies, few studies have evaluated mineral metabolism in CKD according to diabetes status.Using the Chronic Renal Insufficiency Cohort Study, we tested the hypothesis that diabetes is independently associated with lower serum calcium and higher serum phosphate, parathyroid hormone (PTH), and fibroblast growth factor 23 (FGF23).Compared with participants without diabetes (n = 1,936), those with diabetes (n = 1,820) were more likely to have lower estimated glomerular filtration rate (eGFR), lower serum albumin, and higher urinary protein excretion (all P < 0.001). Unadjusted serum phosphate, PTH, and FGF23 levels were higher and calcium was lower among those with compared with those without diabetes (all P < 0.001). After multivariate adjustment, diabetes remained a significant predictor of serum phosphate, PTH, and FGF23 but not calcium. The eGFR cut point at which 50% of participants met criteria for secondary hyperparathyroidism or elevated FGF23 was higher in participants with diabetes compared with those without (PTH: eGFR 30-39 vs. 20-29, P < 0.001; FGF23: eGFR 50-59 vs. 40-49, P < 0.001).Disordered mineral metabolism begins earlier in the course of CKD and is more severe among CKD patients with compared with those without diabetes. Future studies should explore mechanisms for these differences and whether they contribute to excess risks of adverse clinical outcomes among diabetic patients with CKD.

View details for DOI 10.2337/dc11-2235

View details for Web of Science ID 000303218900012

View details for PubMedID 22446176
Vitamin D deficiency is common in children and adolescents with chronic kidney disease KIDNEY INTERNATIONAL Kalkwarf, H. J., Denburg, M. R., Strife, C. F., Zemel, B. S., Foerster, D. L., Wetzsteon, R. J., Leonard, M. B. 2012; 81 (7): 690-697
Abstract

Here we determined if vitamin D deficiency is more common in children with chronic kidney disease compared to healthy children. In addition, we sought to identify disease-specific risk factors for this deficiency, as well as its metabolic consequences. We found that nearly half of 182 patients (ages 5 to 21) with kidney disease (stages 2 to 5) and a third of age-matched 276 healthy children were 25-hydroxyvitamin D deficient (<20 ng/ml). The risk of deficiency was significantly greater in advanced disease. Focal segmental glomerulosclerosis and low albumin were significantly associated with lower 25-hydroxyvitamin D, which, in turn, was associated with significantly higher intact parathyroid hormone levels. We found that 25-hydroxyvitamin D levels were positively associated with 1,25-dihydroxyvitamin D, the relationship being greatest in advanced disease (significant interaction), and inversely related to those of inflammatory markers C-reactive protein and IL-6. The association with C-reactive protein persisted when adjusted for the severity of kidney disease. Thus, lower 25-hydroxyvitamin D may contribute to hyperparathyroidism, inflammation, and lower 1,25-dihydroxyvitamin D in children and adolescents, especially those with advanced kidney disease.

View details for DOI 10.1038/ki.2011.431

View details for Web of Science ID 000301847900011

View details for PubMedID 22205356
Interpretation of Body Mass Index in Children with CKD CLINICAL JOURNAL OF THE AMERICAN SOCIETY OF NEPHROLOGY Gao, T., Leonard, M. B., Zemel, B., Kalkwarf, H. J., Foster, B. J. 2012; 7 (4): 558-564
Abstract

Clinical practice guidelines recommend that body mass index (BMI) in children with CKD be expressed relative to height-age (BMI-height-age-z) rather than chronologic age (BMI-age-z) to account for delayed growth and sexual maturation. This approach has not been validated. This study sought to (1) compare children who have CKD with healthy children regarding the relationships between BMI-age-z and each of relative lean mass (LM) and adiposity and (2) determine whether BMI-height-age-z reflects relative LM and adiposity in CKD in the same way that BMI-age-z does in healthy children.In a cross-sectional study, dual-energy x-ray absorptiometry was used to assess whole-body fat mass (FM) and LM in 143 participants with CKD and 958 healthy participants (age, 5-21 years); FM and LM were expressed as sex-specific Z-scores relative to height (LM-height-z, FM-height-z), with healthy participants as the reference. BMI-age-z and BMI-height-age-z were determined using the 2000 Centers for Disease Control and Prevention reference data.Compared with healthy children of the same sex, age, race, and BMI-age-z, LM-height-z was significantly higher in males with all CKD stages (by 0.41-0.43 SDs) and in females with mild to moderate CKD (by 0.38 SD); FM-height-z was significantly higher in both males (by 0.26 SD) and females (by 0.52 SD) with severe CKD. Underestimation of relative LM and adiposity was improved by expressing BMI relative to height-age.In children with CKD, BMI-height-age-z reflects relative LM and adiposity in the same way that BMI-age-z does in healthy children.

View details for DOI 10.2215/CJN.09710911

View details for Web of Science ID 000302281900007

View details for PubMedID 22300738
Bone Density and Structure in Long-Term Survivors of Pediatric Allogeneic Hematopoietic Stem Cell Transplantation JOURNAL OF BONE AND MINERAL RESEARCH Mostoufi-Moab, S., Ginsberg, J. P., Bunin, N., Zemel, B., Shults, J., Leonard, M. B. 2012; 27 (4): 760-769
Abstract

Children requiring allogeneic hematopoietic stem cell transplantation (alloHSCT) have multiple risk factors for impaired bone accrual. The impact of alloHSCT on volumetric bone mineral density (vBMD) and cortical structure has not been addressed. Tibia peripheral quantitative computed tomography (pQCT) scans were obtained in 55 alloHSCT recipients, ages 5 to 26 years, a median of 7 (range, 3-16) years after alloHSCT. pQCT outcomes were converted to sex- and race- specific Z-scores relative to age based on reference data in >700 concurrent healthy participants. Cortical section modulus (Zp; a summary measure of cortical bone structure and strength), and muscle and fat area Z-scores were further adjusted for tibia length for age Z-scores. AlloHSCT survivors had lower height Z-scores (-1.21 ± 1.25 versus 0.23 ± 0.92; p < 0.001), versus reference participants; BMI Z-scores did not differ. AlloHSCT survivors had lower trabecular vBMD (-1.05; 95% confidence interval [CI], -1.33 to -0.78; p < 0.001), cortical Zp (-0.63; 95% CI, -0.91 to -0.35; p < 0.001), and muscle (-1.01; 95% CI, -1.30 to -0.72; p < 0.001) Z-scores and greater fat (0.82; 95% CI, 0.54-1.11; p < 0.001) Z-scores, versus reference participants. Adjustment for muscle deficits eliminated Zp deficits in alloHSCT. Total body irradiation (TBI) was associated with lower trabecular vBMD (-1.30 ± 1.40 versus -0.49 ± 0.88; p = 0.01) and muscle (-1.34 ± 1.42 versus -0.34 ± 0.87; p < 0.01) Z-scores. Growth hormone deficiency (GHD) was associated with lower Zp Z-scores (-1.64 ± 2.47 versus -0.28 ± 1.24; p = 0.05); however, muscle differences were not significant (-1.69 ± 1.84 versus -0.78 ± 1.01; p = 0.09). History of graft versus host disease was not associated with pQCT outcomes. In summary, alloHSCT was associated with significant deficits in trabecular vBMD, cortical geometry, and muscle area years after transplantation. TBI and GHD were significant risk factors for musculoskeletal deficits. Future studies are needed to determine the metabolic and fracture implications of these deficits, and to identify therapies to improve bone accrual following alloHSCT during childhood.

View details for DOI 10.1002/jbmr.1499

View details for Web of Science ID 000301708100005

View details for PubMedID 22189761
Bone Density and Cortical Structure after Pediatric Renal Transplantation JOURNAL OF THE AMERICAN SOCIETY OF NEPHROLOGY Terpstra, A. M., Kalkwarf, H. J., Shults, J., Zemel, B. S., Wetzsteon, R. J., Foster, B. J., Strife, C. F., Foerster, D. L., Leonard, M. B. 2012; 23 (4): 715-726
Abstract

The impact of renal transplantation on trabecular and cortical bone mineral density (BMD) and cortical structure is unknown. We obtained quantitative computed tomography scans of the tibia in pediatric renal transplant recipients at transplantation and 3, 6, and 12 months; 58 recipients completed at least two visits. We used more than 700 reference participants to generate Z-scores for trabecular BMD, cortical BMD, section modulus (a summary measure of cortical dimensions and strength), and muscle and fat area. At baseline, compared with reference participants, renal transplant recipients had significantly lower mean section modulus and muscle area; trabecular BMD was significantly greater than reference participants only in transplant recipients younger than 13 years. After transplantation, trabecular BMD decreased significantly in association with greater glucocorticoid exposure. Cortical BMD increased significantly in association with greater glucocorticoid exposure and greater decreases in parathyroid hormone levels. Muscle and fat area both increased significantly, but section modulus did not improve. At 12 months, transplantation associated with significantly lower section modulus and greater fat area compared with reference participants. Muscle area and cortical BMD did not differ significantly between transplant recipients and reference participants. Trabecular BMD was no longer significantly elevated in younger recipients and was low in older recipients. Pediatric renal transplant associated with persistent deficits in section modulus, despite recovery of muscle, and low trabecular BMD in older recipients. Future studies should determine the implications of these data on fracture risk and identify strategies to improve bone density and structure.

View details for DOI 10.1681/ASN.2011050480

View details for Web of Science ID 000302333300019

View details for PubMedID 22282589
Micro-MR Imaging-based Computational Biomechanics Demonstrates Reduction in Cortical and Trabecular Bone Strength after Renal Transplantation RADIOLOGY Rajapakse, C. S., Leonard, M. B., Bhagat, Y. A., Sun, W., Magland, J. F., Wehrli, F. W. 2012; 262 (3): 912-920
Abstract

To examine the ability of three-dimensional micro-magnetic resonance (MR) imaging-based computational biomechanics to detect mechanical alterations in trabecular bone and cortical bone in the distal tibia of incident renal transplant recipients 6 months after renal transplantation and compare them with bone mineral density (BMD) outcomes.The study was approved by the institutional review board and complied with HIPAA guidelines. Written informed consent was obtained from all subjects. Micro-MR imaging of distal tibial metaphysis was performed within 2 weeks after renal transplantation (baseline) and 6 months later in 49 participants (24 female; median age, 44 years; range, 19-61 years) with a clinical 1.5-T whole-body imager using a modified three-dimensional fast large-angle spin-echo pulse sequence. Micro-finite-element models for cortical bone, trabecular bone, and whole-bone section were generated from each image by delineating the endosteal and periosteal boundaries. Mechanical parameters (stiffness and failure load) were estimated with simulated uniaxial compression tests on the micro-finite-element models. Structural parameters (trabecular bone volume fraction [BV/TV, bone volume to total volume ratio], trabecular thickness [TbTh], and cortical thickness [CtTh]) were computed from micro-MR images. Total hip and spine areal BMD were determined with dual-energy x-ray absorptiometry (DXA). Parameters obtained at the follow-up were compared with the baseline values by using parametric or nonparametric tests depending on the normality of data.All mechanical parameters were significantly lower at 6 months compared with baseline. Decreases in cortical bone, trabecular bone, and whole-bone stiffness were 3.7% (P = .03), 4.9% (P = .03), and 4.3% (P = .003), respectively. Decreases in cortical bone, trabecular bone, and whole-bone failure strength were 7.6% (P = .0003), 6.0% (P = .004), and 5.6% (P = .0004), respectively. Conventional structural measures, BV/TV, TbTh, and CtTh, did not change significantly. Spine BMD decreased by 2.9% (P < .0001), while hip BMD did not change significantly at DXA.MR imaging-based micro-finite-element analysis suggests that stiffness and failure strength of the distal tibia decrease over a 6-month interval after renal transplantation.

View details for DOI 10.1148/radiol.11111044

View details for Web of Science ID 000302121400020

View details for PubMedID 22357891
Reduced Fracture Risk With Early Corticosteroid Withdrawal After Kidney Transplant AMERICAN JOURNAL OF TRANSPLANTATION Nikkel, L. E., Mohan, S., Zhang, A., McMahon, D. J., Boutroy, S., Dube, G., Tanriover, B., Cohen, D., Ratner, L., Hollenbeak, C. S., Leonard, M. B., Shane, E., Nickolas, T. L. 2012; 12 (3): 649-659
Abstract

Corticosteroid use after kidney transplantation results in severe bone loss and high fracture risk. Although corticosteroid withdrawal in the early posttransplant period has been associated with bone mass preservation, there are no published data regarding corticosteroid withdrawal and risk of fracture. We hypothesized lower fracture incidence in patients discharged from the hospital without than with corticosteroids after transplantation. From the United States Renal Data System (USRDS), 77, 430 patients were identified who received their first kidney transplant from 2000 to 2006. Fracture incidence leading to hospitalization was determined from 2000 to 2007; discharge immunosuppression was determined from United Networks for Organ Sharing forms. Time-to-event analyses were used to evaluate fracture risk. Median (interquartile range) follow-up was 1448 (808-2061) days. There were 2395 fractures during follow-up; fracture incidence rates were 0.008 and 0.0058 per patient-year for recipients discharged with and without corticosteroid, respectively. Corticosteroid withdrawal was associated with a 31% fracture risk reduction (HR 0.69; 95% CI 0.59-0.81). Fractures associated with hospitalization are significantly lower with regimens that withdraw corticosteroid. As this study likely underestimates overall fracture incidence, prospective studies are needed to determine differences in overall fracture risk in patients managed with and without corticosteroids after kidney transplantation.

View details for DOI 10.1111/j.1600-6143.2011.03872.x

View details for Web of Science ID 000300832500022

View details for PubMedID 22151430
Changes in vitamin D binding protein and vitamin D concentrations associated with liver transplantation LIVER INTERNATIONAL Reese, P. P., Bloom, R. D., Feldman, H. I., Huverserian, A., Thomasson, A., Shults, J., Hamano, T., Goral, S., Shaked, A., Olthoff, K., Rickels, M. R., Bleicher, M., Leonard, M. B. 2012; 32 (2): 287-296
Abstract

Vitamin D deficiency is associated with fractures, infections and death. Liver disease impairs vitamin D and vitamin D binding protein (DBP) metabolism.We aimed to determine the impact of liver transplantation on vitamin D, particularly on DBP and free vitamin D concentrations.Serum 25(OH)D, 1,25(OH)(2) D and DBP concentrations were measured in 202 adults before liver transplantation and 3 months later in 155. Free vitamin D concentrations were estimated from these values. Risk factors for 25(OH)D deficiency (<20 ng/ml) and low 1,25(OH)(2) D (<20 pg/ml) were examined with logistic regression, and changes in concentrations following transplantation with linear regression.Pretransplant, 84% were 25(OH)D deficient, 13% had 25(OH)D concentrations <2.5 ng/ml, and 77% had low 1,25(OH)(2) D. Model for end-stage liver disease score ≥ 20 (P < 0.005) and hypoalbuminemia (P < 0.005) were associated with low 25(OH)D and 1,25(OH)(2) D concentrations. Following transplantation, 25(OH)D concentrations increased a median of 17.8 ng/ml (P < 0.001). Albumin increased from a median of 2.7 to 3.8 g/dl (P < 0.001) and DBP from 8.6 to 23.8 mg/dl (P < 0.001). Changes in total 25(OH)D were positively and independently associated with changes in DBP (P < 0.05) and albumin (P < 0.001). Free 25(OH)D concentrations rose from 6.0 to 9.7 pg/ml (P < 0.001). In contrast, total 1,25(OH)(2)D concentrations rose only by 4.3 pg/ml (P < 0.001) and free 1,25(OH)(2D concentrations declined (P < 0.001).Serum total and free 25(OH)D and DBP concentrations rose substantially following transplantation, while 1,25(OH)(2) D concentrations showed modest changes and free 1,25(OH)(2) D decreased. Studies of the effects of vitamin D status on diverse transplant complications are needed.

View details for DOI 10.1111/j.1478-3231.2011.02638.x

View details for Web of Science ID 000298919500014

View details for PubMedID 22098635
Associations Between Psychiatric Comorbidities and Sleep Disturbances in Children With Attention-Deficit/Hyperactivity Disorder JOURNAL OF DEVELOPMENTAL AND BEHAVIORAL PEDIATRICS Accardo, J. A., Marcus, C. L., Leonard, M. B., Shults, J., Meltzer, L. J., Elia, J. 2012; 33 (2): 97-105
Abstract

Children with attention-deficit/hyperactivity disorder (ADHD) often have sleep complaints and also higher rates of psychiatric comorbidities such as mood and anxiety disorders that may affect sleep. The authors hypothesized that children with ADHD and psychiatric comorbidities would have higher overall sleep disturbance scores as measured by a sleep questionnaire than children with ADHD without comorbidities.This cross-sectional analysis in an academic center studied 317 children with ADHD; 195 subjects had no comorbid conditions, 60 were anxious and 62 were depressed. Participants completed the Schedule for Affective Disorders and Schizophrenia for School-Age Children-Present State, 4th Revised Edition and the Children's Sleep Habits Questionnaire.Median age (range) was 8.9 (6-18.7) years; 78% were male. Median (interquartile range) Total Sleep Disturbance Score (TSDS) on Children's Sleep Habits Questionnaire for subjects with no comorbidities was 44 (40-49); anxiety, 48 (43-54); and depression, 46 (41-52). Compared with subjects without comorbidities, TSDS in anxious subjects was greater (p = .008). TSDS in depressed subjects was not significantly different. Compared with subjects without comorbidities, anxious subjects had higher Bedtime Resistance, Sleep Onset Delay, and Night Wakings subscales (p = .03, .007, and .007, respectively); depressed subjects had higher Sleep Onset Delay and Sleep Duration subscales (p = .003 and .01, respectively).Anxiety in children with ADHD contributed to higher overall sleep disturbance scores, compared with children with ADHD alone. Both comorbidities were associated with higher Sleep Onset Latency subscale scores. Further study of the impact of psychiatric comorbidities on sleep in children with ADHD is warranted.

View details for DOI 10.1097/DBP.0b013e31823f6853

View details for Web of Science ID 000300399700001

View details for PubMedID 22261833
Body Composition Abnormalities in Long-Term Survivors of Pediatric Hematopoietic Stem Cell Transplantation JOURNAL OF PEDIATRICS Mostoufi-Moab, S., Ginsberg, J. P., Bunin, N., Zemel, B. S., Shults, J., Thayu, M., Leonard, M. B. 2012; 160 (1): 122-128
Abstract

To quantify lean mass (LM) and fat mass (FM) in survivors of childhood allogeneic hematopoietic stem-cell transplantation (alloHSCT) compared with healthy reference participants and identify risk factors for body composition abnormalities.Whole body LM and FM were measured with dual energy x-ray absorptiometry in 54 survivors (ages 5-25 years) and 894 healthy reference participants in a cross-sectional study. Multivariate regression models were used to compare sex- and race-specific Z-scores for LM for height (LM-Ht) and FM for height (FM-Ht) in survivors and reference participants and to identify correlates of LM-Ht and FM-Ht Z-scores in alloHSCT.Height Z-scores were significantly lower in alloHSCT survivors (P < .001) compared with reference participants; body mass index Z-scores did not differ (P = .13). Survivors had significantly lower mean LM-Ht Z-scores (-0.72; 95% CI, -1.02--0.42; P < .001) and greater FM-Ht Z-scores (1.10; 95% CI, 0.84-1.39; P < .001) compared with reference participants. LM-Ht Z-score deficits in alloHSCT survivors were larger (-1.26; 95% CI, -1.53--0.99; P < .001) after adjustment for FM-Ht Z-scores. Endocrinopathies and alloHSCT characteristics were not associated with LM-Ht or FM-Ht Z-scores.Survivors of childhood alloHSCT have significant LM deficits and FM excess. Future studies should identify the mechanism and consequences of these abnormalities.

View details for DOI 10.1016/j.jpeds.2011.06.041

View details for Web of Science ID 000298143000029

View details for PubMedID 21839468
Correlates of Osteoprotegerin and Association with Aortic Pulse Wave Velocity in Patients with Chronic Kidney Disease CLINICAL JOURNAL OF THE AMERICAN SOCIETY OF NEPHROLOGY Scialla, J. J., Leonard, M. B., Townsend, R. R., Appel, L., Wolf, M., Budoff, M. J., Chen, J., Lustigova, E., Gadegbeku, C. A., Glenn, M., Hanish, A., Raj, D., Rosas, S. E., Seliger, S. L., Weir, M. R., Parekh, R. S. 2011; 6 (11): 2612-2619
Abstract

Osteoprotegerin (OPG), a cytokine that regulates bone resorption, has been implicated in the process of vascular calcification and stiffness.Serum OPG was measured in 351 participants with chronic kidney disease (CKD) from one site of the Chronic Renal Insufficiency Cohort Study. Cortical bone mineral content (BMC) was measured by quantitative computed tomography in the tibia. Multivariable linear regression was used to test the association between serum OPG and traditional cardiovascular risk factors, measures of abnormal bone and mineral metabolism, and pulse wave velocity.Higher serum OPG levels were associated with older age, female gender, greater systolic BP, lower estimated GFR, and lower serum albumin. OPG was not associated with measures of abnormal bone or mineral metabolism including serum phosphorus, albumin-corrected serum calcium, intact parathyroid hormone, bone-specific alkaline phosphatase, or cortical BMC. Among 226 participants with concurrent aortic pulse wave velocity measurements, increasing tertiles of serum OPG were associated with higher aortic pulse wave velocity after adjustment for demographics, traditional vascular risk factors, and nontraditional risk factors such as estimated GFR, albuminuria, serum phosphate, corrected serum calcium, presence of secondary hyperparathyroidism, serum albumin, and C-reactive protein or after additional adjustment for cortical BMC in a subset (n = 161).These data support a strong relationship between serum OPG and arterial stiffness independent of many potential confounders including traditional cardiovascular risk factors, abnormal bone and mineral metabolism, and inflammation.

View details for DOI 10.2215/CJN.03910411

View details for Web of Science ID 000296821300011

View details for PubMedID 21940840
Validation of The Health Improvement Network (THIN) database for epidemiologic studies of chronic kidney disease PHARMACOEPIDEMIOLOGY AND DRUG SAFETY Denburg, M. R., Haynes, K., Shults, J., Lewis, J. D., Leonard, M. B. 2011; 20 (11): 1138-1149
Abstract

Chronic kidney disease (CKD) is a prevalent and important outcome and covariate in pharmacoepidemiology. The Health Improvement Network (THIN) in the UK represents a unique resource for population-based studies of CKD. We compiled a valid list of Read codes to identify subjects with moderate to advanced CKD.A cross-sectional validation study was performed to identify codes that best define CKD Stages 3-5. All subjects with at least one non-zero measure of serum creatinine after 1 January 2002 were included. Estimated glomerular filtration rate (eGFR) was calculated according to the Schwartz formula for subjects aged < 18 years and the Modification of Diet in Renal Disease formula for subjects aged ≥ 18 years. CKD was defined as an eGFR <60 mL/minute/1.73 m² on at least two occasions, more than 90 days apart.The laboratory definition identified 230,426 subjects with CKD, for a period prevalence in 2008 of 4.56% (95%CI, 4.54-4.58). A list of 45 Read codes was compiled, which yielded a positive predictive value of 88.9% (95%CI, 88.7-89.1), sensitivity of 48.8%, negative predictive value of 86.5%, and specificity of 98.2%. Of the 11.1% of subjects with a code who did not meet the laboratory definition, 83.6% had at least one eGFR <60. The most commonly used code was for CKD Stage 3.The proposed list of codes can be used to accurately identify CKD when serum creatinine data are limited. The most sensitive approach for the detection of CKD is to use this list to supplement creatinine measures.

View details for DOI 10.1002/pds.2203

View details for Web of Science ID 000296974300003

View details for PubMedID 22020900
Associations between body mass, radiographic joint damage, adipokines and risk factors for bone loss in rheumatoid arthritis RHEUMATOLOGY Baker, J. F., George, M., Baker, D. G., Toedter, G., Von Feldt, J. M., Leonard, M. B. 2011; 50 (11): 2100-2107
Abstract

To evaluate the association between BMI and radiographic joint damage (RJD) in RA.van der Heijde-Sharp (vdHS) erosion scores were determined in 499 participants with RA, ages 18-85 years, while enrolled in a clinical trial of golimumab (GO-BEFORE trial). Subjects were MTX and biologic therapy naïve. Multivariable logistic regressions determined the odds of prevalent RJD (defined as vdHS score >10) according to BMI category. Longitudinal analyses evaluated the association between BMI category and progression of vdHS score over 52 weeks. Analyses in a subset of 100 participants examined the association between adipokines and vdHS scores.At enrolment and 52 weeks, 37.6 and 43.6% of participants had RJD. Compared with normal weight, obese subjects had lower odds of RJD [0.40 (95% CI 0.22, 0.74); P = 0.003], and underweight subjects had greater odds [3.86 (95% CI 1.66, 9.00); P = 0.002] at baseline, adjusted for demographic and disease characteristics. The baseline associations between BMI category and RJD were greater among participants with multiple risk factors for bone loss (female >50 years, smoking, glucocorticoid exposure and vitamin D deficiency); test for interaction P = 0.05. Adjustment for adiponectin levels did not attenuate the association between BMI and vdHS scores. Baseline BMI and change in weight did not independently predict radiographic progression (P > 0.1).Higher BMI was independently associated with less RJD and was greatest in participants with risk factors for bone loss. Future studies are needed to examine the associations between RJD, obesity, weight loss and osteoporosis.

View details for DOI 10.1093/rheumatology/ker294

View details for Web of Science ID 000296295800025

View details for PubMedID 21890621
On the Significance of Motion Degradation in High-resolution 3D mu MRI of Trabecular Bone ACADEMIC RADIOLOGY Bhagat, Y. A., Rajapakse, C. S., Magland, J. F., Wald, M. J., Song, H. K., Leonard, M. B., Wehrli, F. W. 2011; 18 (10): 1205-1216
Abstract

Subtle subject movement during high-resolution three-dimensional micro-magnetic resonance imaging of trabecular bone (TB) causes blurring, thereby rendering the data unreliable for quantitative analysis. In this work, the effects of translational and rotational motion displacements were evaluated qualitatively and quantitatively.In experiment 1, motion was induced by applying various simulated and previously observed in vivo trajectories as phase shifts to k-space or rotation angles to k-space segments of a virtually motion-free data set. In experiment 2, images that were visually free of motion artifacts from two groups of 10 healthy individuals, differing in age, were selected to probe the effects of motion on TB parameters. In both experiments, images were rated for motion severity, and the scores were compared to a focus criterion, the normalized gradient squared.Strong correlations were observed between the motion quality scores and the corresponding normalized gradient squared values (R(2) = 0.52-0.64, P < .01). The results from experiment 1 demonstrated consistently lower image quality and alterations in structural parameters of 9% to 45% with increased amplitude of displacements. In experiment 2, the significant differences in structural parameter group means of the motion-free images were lost upon motion degradation. Autofocusing, a postprocessing correction method, partially recovered the sharpness of the original motion-free images in 13 of 20 subjects.Quantitative TB structural measures are highly sensitive to subtle motion-induced degradation, which adversely affects precision and statistical power. The results underscore the influence of subject movement in high-resolution three-dimensional micro-magnetic resonance imaging and its correction for TB structure analysis.

View details for DOI 10.1016/j.acra.2011.06.006

View details for Web of Science ID 000295344500002

View details for PubMedID 21816638
Volumetric Bone Mineral Density and Bone Structure in Childhood Chronic Kidney Disease JOURNAL OF BONE AND MINERAL RESEARCH Wetzsteon, R. J., Kalkwarf, H. J., Shults, J., Zemel, B. S., Foster, B. J., Griffin, L., Strife, C. F., Foerster, D. L., Jean-Pierre, D. K., Leonard, M. B. 2011; 26 (9): 2235-2244
Abstract

Chronic kidney disease (CKD) is associated with increased fracture risk and skeletal deformities. The impact of CKD on volumetric bone mineral density (vBMD) and cortical dimensions during growth is unknown. Tibia quantitative computed tomographic scans were obtained in 156 children with CKD [69 stages 2 to 3, 51 stages 4 to 5, and 36 stage 5D (dialysis)] and 831 healthy participants aged 5 to 21 years. Sex-, race-, and age- or tibia length-specific Z-scores were generated for trabecular BMD (TrabBMD), cortical BMD (CortBMD), cortical area (CortArea) and endosteal circumference (EndoC). Greater CKD severity was associated with a higher TrabBMD Z-score in younger participants (p < .001) compared with healthy children; this association was attenuated in older participants (interaction p < .001). Mean CortArea Z-score was lower (p < .01) in CKD 4-5 [-0.49, 95% confidence interval (CI) -0.80, -0.18)] and CKD 5D (-0.49, 95% CI -0.83, -0.15) compared with healthy children. Among CKD participants, parathyroid hormone (PTH) levels were positively associated with TrabBMD Z-score (p < .01), and this association was significantly attenuated in older participants (interaction p < .05). Higher levels of PTH and biomarkers of bone formation (bone-specific alkaline phosphatase) and resorption (serum C-terminal telopeptide of type 1 collagen) were associated with lower CortBMD and CortArea Z-scores and greater EndoC Z-score (r = 0.18-0.36, all p ≤ .02). CortBMD Z-score was significantly lower in CKD participants with PTH levels above versus below the upper limit of the Kidney Disease Outcome Quality Initiative (KDOQI) CKD stage-specific target range: -0.46 ± 1.29 versus 0.12 ± 1.14 (p < .01). In summary, childhood CKD and secondary hyperparathyroidism were associated with significant reductions in cortical area and CortBMD and greater TrabBMD in younger children. Future studies are needed to establish the fracture implications of these alterations and to determine if cortical and trabecular abnormalities are reversible.

View details for DOI 10.1002/jbmr.427

View details for Web of Science ID 000294444300024

View details for PubMedID 21590737
Discriminants of Prevalent Fractures in Chronic Kidney Disease JOURNAL OF THE AMERICAN SOCIETY OF NEPHROLOGY Nickolas, T. L., Cremers, S., Zhang, A., Thomas, V., Stein, E., Cohen, A., Chauncey, R., Nikkel, L., Yin, M. T., Liu, X. S., Boutroy, S., Staron, R. B., Leonard, M. B., McMahon, D. J., Dworakowski, E., Shane, E. 2011; 22 (8): 1560-1572
Abstract

Patients with chronic kidney disease (CKD) have higher rates of fracture than the general population. Increased bone remodeling, leading to microarchitectural deterioration and increased fragility, may accompany declining kidney function, but there are no reliable methods to identify patients at increased risk for fracture. In this cross-sectional study of 82 patients with predialysis CKD, high-resolution imaging revealed that the 23 patients with current fractures had significantly lower areal density at the femoral neck; total, cortical, and trabecular volumetric bone density; cortical area and thickness; and trabecular thickness. Compared with levels in the lowest tertile, higher levels of osteocalcin, procollagen type-1 N-terminal propeptide, and tartrate-resistant acid phosphatase 5b were associated with higher odds of fracture, even after adjustment for femoral neck T-score. Discrimination of fracture prevalence was best with a femoral neck T-score of -2.0 or less and a value in the upper two tertiles for osteocalcin, procollagen type-1 N-terminal propeptide, or tartrate-resistant acid phosphatase 5b; these values corresponded to the upper half of the normal premenopausal reference range. In summary, these cross-sectional data suggest that measurement of bone turnover markers may increase the diagnostic accuracy of densitometry to identify patients with CKD at high risk for fracture.

View details for DOI 10.1681/ASN.2010121275

View details for Web of Science ID 000294083300023

View details for PubMedID 21784896
Skeletal Health of Children and Adolescents With Inflammatory Bowel Disease JOURNAL OF PEDIATRIC GASTROENTEROLOGY AND NUTRITION Pappa, H., Thayu, M., Sylvester, F., Leonard, M., Zemel, B., Gordon, C. 2011; 53 (1): 11-25
Abstract

Current evidence points to suboptimal bone health in children and adolescents with inflammatory bowel disease (IBD) when compared with their healthy peers. This compromise is evident from diagnosis. The clinical consequences and long-term outcome of this finding are still unknown. The mechanism of suboptimal bone health in children and adolescents with IBD lays mainly in reduced bone formation, but also reduced bone resorption, processes necessary for bone growth. Factors contributing to this derangement are inflammation, delayed growth and puberty, lean mass deficits, and use of glucocorticoids. We recognize that evidence is sparse on the topic of bone health in children and adolescents with IBD. In this clinical guideline, based on current evidence, we provide recommendations on screening and monitoring bone health in children and adolescents with IBD, including modalities to achieve this and their limitations; monitoring of parameters of growth, pubertal development, and reasons for concern; evaluation of vitamin D status and vitamin D and calcium intake; exercise; and nutritional support. We also report on the current evidence of the effect of biologics on bone health in children and adolescents with IBD, as well as the role of bone active medications such as bisphosphonates. Finally, we summarize the existing numerous gaps in knowledge and potential subjects for future research endeavors.

View details for DOI 10.1097/MPG.0b013e31821988a3

View details for Web of Science ID 000291925500003

View details for PubMedID 21694532
Circulating MicroRNA Is a Biomarker of Pediatric Crohn Disease JOURNAL OF PEDIATRIC GASTROENTEROLOGY AND NUTRITION Zahm, A. M., Thayu, M., Hand, N. J., Horner, A., Leonard, M. B., Friedman, J. R. 2011; 53 (1): 26-33
Abstract

The gold standard for the diagnosis and evaluation of Crohn disease (CD) is endoscopy/colonoscopy, although this is invasive, costly, and associated with risks to the patient. Recently, circulating microRNAs (miRNAs) have emerged as promising noninvasive biomarkers. Here, we examined the utility of serum miRNAs as biomarkers of CD in children.Studies were conducted using sera samples from patients with pediatric CD, healthy controls, and a comparison group of patients with pediatric celiac disease. Serum miRNA levels were explored initially using a microfluidic quantitative reverse transcription-polymerase chain reaction array platform. Findings were subsequently validated using quantitative reverse transcription-polymerase chain reaction in larger validation sample sets. The diagnostic utility of CD-associated serum miRNA was examined using receiver operating characteristic analysis.A survey of miRNA levels in the sera of control and patients with CD detected significant elevation of 24 miRNAs, 11 of which were chosen for further validation. All of the candidate biomarker miRNAs were confirmed in an independent CD sample set (n = 46). To explore the specificity of the CD-associated miRNAs, they were measured in the sera of patients with celiac disease (n = 12); none were changed compared with healthy controls. Receiver operating characteristic analyses revealed that serum miRNAs have promising diagnostic utility, with sensitivities for CD above 80%. Significant decreases in serum miRNAs were observed in 24 incident patients with pediatric CD after 6 months of treatment.The present study identifies 11 CD-associated serum miRNA with encouraging diagnostic potential. Our findings suggest serum miRNAs may prove useful as noninvasive biomarkers in CD.

View details for DOI 10.1097/MPG.0b013e31822200cc

View details for Web of Science ID 000291925500004

View details for PubMedID 21546856
Fibroblast Growth Factor 23 and Risks of Mortality and End-Stage Renal Disease in Patients With Chronic Kidney Disease JAMA-JOURNAL OF THE AMERICAN MEDICAL ASSOCIATION Isakova, T., Xie, H., Yang, W., Xie, D., Anderson, A. H., Scialla, J., Wahl, P., Gutierrez, O. M., Steigerwalt, S., He, J., Schwartz, S., Lo, J., Ojo, A., Sondheimer, J., Hsu, C., Lash, J., Leonard, M., Kusek, J. W., Feldman, H. I., Wolf, M. 2011; 305 (23): 2432-2439
Abstract

A high level of the phosphate-regulating hormone fibroblast growth factor 23 (FGF-23) is associated with mortality in patients with end-stage renal disease, but little is known about its relationship with adverse outcomes in the much larger population of patients with earlier stages of chronic kidney disease.To evaluate FGF-23 as a risk factor for adverse outcomes in patients with chronic kidney disease.A prospective study of 3879 participants with chronic kidney disease stages 2 through 4 who enrolled in the Chronic Renal Insufficiency Cohort between June 2003 and September 2008.All-cause mortality and end-stage renal disease.At study enrollment, the mean (SD) estimated glomerular filtration rate (GFR) was 42.8 (13.5) mL/min/1.73 m(2), and the median FGF-23 level was 145.5 RU/mL (interquartile range [IQR], 96-239 reference unit [RU]/mL). During a median follow-up of 3.5 years (IQR, 2.5-4.4 years), 266 participants died (20.3/1000 person-years) and 410 reached end-stage renal disease (33.0/1000 person-years). In adjusted analyses, higher levels of FGF-23 were independently associated with a greater risk of death (hazard ratio [HR], per SD of natural log-transformed FGF-23, 1.5; 95% confidence interval [CI], 1.3-1.7). Mortality risk increased by quartile of FGF-23: the HR was 1.3 (95% CI, 0.8-2.2) for the second quartile, 2.0 (95% CI, 1.2-3.3) for the third quartile, and 3.0 (95% CI, 1.8-5.1) for the fourth quartile. Elevated fibroblast growth factor 23 was independently associated with significantly higher risk of end-stage renal disease among participants with an estimated GFR between 30 and 44 mL/min/1.73 m(2) (HR, 1.3 per SD of FGF-23 natural log-transformed FGF-23; 95% CI, 1.04-1.6) and 45 mL/min/1.73 m(2) or higher (HR, 1.7; 95% CI, 1.1-2.4), but not less than 30 mL/min/1.73 m(2).Elevated FGF-23 is an independent risk factor for end-stage renal disease in patients with relatively preserved kidney function and for mortality across the spectrum of chronic kidney disease.

View details for DOI 10.1001/jama.2011.826

View details for Web of Science ID 000291597300023

View details for PubMedID 21673295
Fibroblast growth factor 23 is elevated before parathyroid hormone and phosphate in chronic kidney disease KIDNEY INTERNATIONAL Isakova, T., Wahl, P., Vargas, G. S., Gutierrez, O. M., Scialla, J., Xie, H., Appleby, D., Nessel, L., Bellovich, K., Chen, J., Hamm, L., Gadegbeku, C., Horwitz, E., Townsend, R. R., Anderson, C. A., Lash, J. P., Hsu, C., Leonard, M. B., Wolf, M. 2011; 79 (12): 1370-1378
Abstract

Fibroblast growth factor 23 (FGF23) regulates phosphorus metabolism and is a strong predictor of mortality in dialysis patients. FGF23 is thought to be an early biomarker of disordered phosphorus metabolism in the initial stages of chronic kidney disease (CKD). We measured FGF23 in baseline samples from 3879 patients in the Chronic Renal Insufficiency Cohort study, which is a diverse cohort of patients with CKD stage 2-4. Mean serum phosphate and median parathyroid hormone (PTH) levels were in the normal range, but median FGF23 was markedly greater than in healthy populations, and increased significantly with decreasing estimated glomerular filtration rate (eGFR). High levels of FGF23, defined as being above 100 RU/ml, were more common than secondary hyperparathyroidism and hyperphosphatemia in all strata of eGFR. The threshold of eGFR at which the slope of FGF23 increased was significantly higher than the corresponding threshold for PTH based on non-overlapping 95% confidence intervals. Thus, increased FGF23 is a common manifestation of CKD that develops earlier than increased phosphate or PTH. Hence, FGF23 measurements may be a sensitive early biomarker of disordered phosphorus metabolism in patients with CKD and normal serum phosphate levels.

View details for DOI 10.1038/ki.2011.47

View details for Web of Science ID 000291093300013

View details for PubMedID 21389978
Exposure to CYP3A4-inducing and CYP3A4-non-inducing antiepileptic agents and the risk of fractures PHARMACOEPIDEMIOLOGY AND DRUG SAFETY Schelleman, H., Pollard, J. R., Newcomb, C., Markowitz, C. E., Bilker, W. B., Leonard, M. B., Hennessy, S. 2011; 20 (6): 619-625
Abstract

To evaluate whether exposure to Cytochrome P450, family 3, subfamily A, polypeptide 4 (CYP3A4)-inducing antiepileptics increases fracture risk compared to CYP3A4-non-inducing antiepileptics.We performed a retrospective cohort study of initiators of antiepileptic agents using a UK medical record database (The Health Improvement Network) from 1995 to 2007. We considered an antiepileptic user an initiator if he or she had not received a prescription for an antiepileptic agent within the first year after entry in the database. Proportional hazards regression was used to calculate hazard ratios for fracture during long-term (≥ 6 months) exposure to CYP3A4 inducing versus CYP3A4 non-inducing antiepileptics.We identified 4077 initiators of CYP3A4-inducing antiepileptics and 6433 initiators of CYP3A4-non-inducing antiepileptics with at least 6 months of antiepileptic exposure. During 6006 person-years exposed to CYP3A4-inducing antiepileptics, 118 fractures were identified for an incidence rate of 1.96 (95% confidence interval (CI): 1.63-2.35) fractures per 100 person-years. During 7184 person-years exposed to CYP3A4-non-inducing antiepileptics, 127 fractures were identified, for an incidence rate of 1.77 (95% CI: 1.47-2.10) fractures per 100 person-years. The adjusted hazard ratio for CYP3A4-inducing antiepileptic versus CYP3A4-non-inducing antiepileptic was 1.21 (95% CI: 0.93-1.56). No duration-response relationship was evident.Our results do not support the hypothesis that CYP3A4 induction by antiepileptic agents increases the fracture risk. Further research will be needed to evaluate whether mechanisms other than CYP3A4 induction might explain some of the elevated risk of fractures associated with long-term use of antiepileptic agents.

View details for DOI 10.1002/pds.2141

View details for Web of Science ID 000292601300008

View details for PubMedID 21538673
Mechanical loads and cortical bone geometry in healthy children and young adults BONE Wetzsteon, R. J., Zemel, B. S., Shults, J., Howard, K. M., Kibe, L. W., Leonard, M. B. 2011; 48 (5): 1103-1108
Abstract

Muscle and bone form a functional unit. While muscle size is a useful surrogate of mechanical load on bone, the independent contributions to bone strength of muscle force, muscle size, gravitational load (body weight), and physical activity have not been assessed. Three hundred twenty-one healthy participants (32% black, 47% male), aged 5-35 years were assessed. Peak dorsiflexion muscle torque (ft-lbs) of the ankle was assessed using isometric dynamometry. Tibia peripheral quantitative computed tomography measures included polar section modulus (Zp; mm(3)), periosteal and endosteal circumference (mm), cortical area (mm(2)), and volumetric bone mineral density (vBMD; mg/cm(3)) at the 38% site, and muscle cross-sectional area (CSA; mm(2)), at the 66% site. Physical activity (average hours per week) was assessed by questionnaire. Log linear regression was used to assess determinants of muscle specific force (MSF; torque relative to muscle CSA) and Zp adjusted for age and tibia length. MSF was greater in blacks than whites (p<0.05) and lower in females than males (p<0.001). Zp was greater in blacks than whites (p=0.002) in Tanner stages 1-4, but the difference was attenuated in Tanner 5 (interaction, p=0.02); R(2)=0.87. Muscle CSA, muscle torque, body weight, and physical activity were added to the model and each load covariate was independently and significantly (all, p<0.02) associated with Zp (R(2)=0.92), periosteal circumference, and cortical area. Inclusion of these measures attenuated but did not eliminate the significant race differences. Only muscle CSA was positively associated with endosteal circumference, while none of the load covariates were associated with vBMD. In conclusion, bone geometry is associated with several factors that define the mechanical load on bone, independent of age, tibia length, maturation, race, and sex. Race differences in Zp were not explained by these measures of mechanical load. Given that inclusion of muscle torque, body weight, and physical activity resulted in a nominal increase in the R(2), muscle size is an adequate surrogate for the mechanical load on bone in healthy participants.

View details for DOI 10.1016/j.bone.2011.01.005

View details for Web of Science ID 000289879900019

View details for PubMedID 21241839
Diuretics, calciuria and secondary hyperparathyroidism in the Chronic Renal Insufficiency Cohort (CRIC) NEPHROLOGY DIALYSIS TRANSPLANTATION Isakova, T., Anderson, C. A., Leonard, M. B., Xie, D., Gutierrez, O. M., Rosen, L. K., Theurer, J., Bellovich, K., Steigerwalt, S. P., Tang, I., Anderson, A. H., Townsend, R. R., He, J., Feldman, H. I., Wolf, M. 2011; 26 (4): 1258-1265
Abstract

Secondary hyperparathyroidism is a common complication of chronic kidney disease (CKD) that is associated with bone disease, cardiovascular disease and death. Pathophysiological factors that maintain secondary hyperparathyroidism in advanced CKD are well-known, but early mechanisms of the disease that can be targeted for its primary prevention are poorly understood. Diuretics are widely used to control volume status and blood pressure in CKD patients but are also known to have important effects on renal calcium handling, which we hypothesized could alter the risk of secondary hyperparathyroidism.We examined the relationship of diuretic treatment with urinary calcium excretion, parathyroid hormone (PTH) levels and prevalence of secondary hyperparathyroidism (PTH ≥ 65 pg/mL) in a cross-sectional study of 3616 CKD patients in the Chronic Renal Insufficiency Cohort.Compared with no diuretics, treatment with loop diuretics was independently associated with higher adjusted urinary calcium (55.0 versus 39.6 mg/day; P < 0.001), higher adjusted PTH [67.9, 95% confidence interval (CI) 65.2-70.7 pg/mL, versus 52.8, 95% CI 51.1-54.6 pg/mL, P < 0.001] and greater odds of secondary hyperparathyroidism (odds ratio 2.1; 95% CI 1.7-2.6). Thiazide monotherapy was associated with lower calciuria (25.5 versus 39.6 mg/day; P < 0.001) but only modestly lower PTH levels (50.0, 95% CI 47.8-52.3, versus 520.8, 95% CI 51.1-54.6 pg/mL, P = 0.04) compared with no diuretics. However, coadministration of thiazide and loop diuretics was associated with blunted urinary calcium (30.3 versus 55.0 mg/day; P <0.001) and odds of hyperparathyroidism (odds ratio 1.3 versus 2.1; P for interaction = 0.05) compared with loop diuretics alone.Loop diuretic use was associated with greater calciuria, PTH levels and odds of secondary hyperparathyroidism compared to no treatment. These associations were attenuated in patients who were coadministered thiazides. Diuretic choice is a potentially modifiable determinant of secondary hyperparathyroidism in CKD.

View details for DOI 10.1093/ndt/gfr026

View details for Web of Science ID 000289309400023

View details for PubMedID 21382989
Association of Chronic Kidney Disease with Muscle Deficits in Children JOURNAL OF THE AMERICAN SOCIETY OF NEPHROLOGY Foster, B. J., Kalkwarf, H. J., Shults, J., Zemel, B. S., Wetzsteon, R. J., Thayu, M., Foerster, D. L., Leonard, M. B. 2011; 22 (2): 377-386
Abstract

The effect of chronic kidney disease (CKD) on muscle mass in children, independent of poor growth and delayed maturation, is not well understood. We sought to characterize whole body and regional lean mass (LM) and fat mass (FM) in children and adolescents with CKD and to identify correlates of LM deficits in CKD. We estimated LM and FM from dual energy x-ray absorptiometry scans in 143 children with CKD and 958 controls at two pediatric centers. We expressed whole body, trunk, and leg values of LM and FM as Z-scores relative to height, sitting height, and leg length, respectively, using the controls as the reference. We used multivariable regression models to compare Z-scores in CKD and controls, adjusted for age and maturation, and to identify correlates of LM Z-scores in CKD. Greater CKD severity associated with greater leg LM deficits. Compared with controls, leg LM Z-scores were similar in CKD stages 2 to 3 (difference: 0.02 [95% CI: -0.20, 0.24]; P = 0.8), but were lower in CKD stages 4 to 5 (-0.41 [-0.66, -0.15]; P = 0.002) and dialysis (-1.03 [-1.33, -0.74]; P < 0.0001). Among CKD participants, growth hormone therapy associated with greater leg LM Z-score (0.58 [0.03, 1.13]; P = 0.04), adjusted for CKD severity. Serum albumin, bicarbonate, and markers of inflammation did not associate with LM Z-scores. CKD associated with greater trunk LM and FM, variable whole body LM, and normal leg FM, compared with controls. In conclusion, advanced CKD associates with significant deficits in leg lean mass, indicating skeletal muscle wasting. These data call for prospective studies of interventions to improve muscle mass among children with CKD.

View details for DOI 10.1681/ASN.2010060603

View details for Web of Science ID 000287673600024

View details for PubMedID 21115614
Vitamin D deficiency and parathyroid hormone levels following renal transplantation in children PEDIATRIC NEPHROLOGY Tuchman, S., Kalkwarf, H. J., Zemel, B. S., Shults, J., Wetzsteon, R. J., Foerster, D., Strife, C. F., Leonard, M. B. 2010; 25 (12): 2509-2516
Abstract

The objectives were to determine the prevalence of vitamin D deficiency [25(OH)D < 10 ng/ml] in pediatric renal transplant (RTx) recipients, compared with controls and identify correlates of changes in 25(OH)D and intact parathyroid hormone (iPTH) levels following transplantation. Serum 25(OH)D, 1,25(OH)(2)D, and iPTH were measured once in 275 healthy controls and at transplantation, and 3 and 12 months posttransplantation in 58 RTx recipients. Multivariate logistic regression models determined the odds ratio (OR) of vitamin D deficiency in RTx recipients vs. controls adjusted for age, sex, race, and season. Generalized estimating equations were used to assess changes following transplantation. At transplantation, 22% of nonblack and 27% of black RTx recipients were vitamin D deficient. The adjusted OR of vitamin D deficiency was greater in RTx recipients (p < 0.001) compared with controls; however, the transplant association was greater in nonblack vs. black individuals (interaction p = 0.02). Overall, 25(OH)D levels did not change significantly following transplantation. Younger age (p < 0.01), nonblack race (p < 0.001), visits in nonwinter months (p < 0.001), and supplementation with ≥400 IU/day ergo/cholecalciferol (p < 0.001) were associated with increases (or lesser declines) in 25(OH)D following transplantation. Increases in 25(OH)D levels (p < 0.001) and vitamin D supplementation (p < 0.01) were associated with greater reductions in iPTH levels following transplantation, independent of 1,25(OH)(2)D levels.

View details for DOI 10.1007/s00467-010-1612-0

View details for Web of Science ID 000283366600015

View details for PubMedID 20872272
Longitudinal relations between obesity and hypertension following pediatric renal transplantation PEDIATRIC NEPHROLOGY Denburg, M. R., Pradhan, M., Shults, J., Jones, A., Palmer, J. A., Baluarte, H. J., Leonard, M. B. 2010; 25 (10): 2129-2139
Abstract

Obesity and hypertension frequently complicate renal transplantation (RTxp). The objective was to assess relations among obesity, hypertension, and glucocorticoids in pediatric RTxp recipients. A retrospective cohort study was carried out in 141 RTxp recipients, 2-21 years of age, with >or=12 months of follow-up. Body mass index Z-score (BMI-Z), systolic and diastolic blood pressure Z-scores (SBP-Z and DBP-Z), and medications at 1, 3, 6, and 12 months and annually thereafter were recorded. Quasi-least squares regression analysis was used. The prevalence of obesity (BMI>or=95th percentile) increased from 13% at baseline to >30% from 3 months onward. Greater glucocorticoid exposure (mg/kg/day) was associated with greater increases in BMI-Z (p<0.001). This association was greater in males, younger recipients, and those with lower baseline BMI-Z (all interactions p<0.02). The prevalence of systolic hypertension (SBP>or=95th percentile) was 73% at 1 month and >or=40% at all follow-up visits. Greater glucocorticoid exposure (p<0.001) and increases in BMI-Z (p=0.005) were independent determinants of SBP-Z over time. Cyclosporine (versus tacrolimus) was independently associated with greater SBP-Z and DBP-Z (p=0.001). Sustained obesity and hypertension frequently complicated pediatric RTxp. Obesity was an independent determinant of systolic hypertension. Strategies are needed to prevent obesity and its impact on hypertension, cardiovascular disease, and allograft survival.

View details for DOI 10.1007/s00467-010-1572-4

View details for Web of Science ID 000281110700015

View details for PubMedID 20567855
Changing Indications for Upper Endoscopy in Children During a 20-year Period JOURNAL OF PEDIATRIC GASTROENTEROLOGY AND NUTRITION Franciosi, J. P., Fiorino, K., Ruchelli, E., Shults, J., Spergel, J., Liacouras, C. A., Leonard, M. 2010; 51 (4): 443-447
Abstract

In parallel with the increase in pediatric esophagogastroduodenoscopy (EGD) procedures since the 1970s, the incidence of disorders that require EGD for diagnosis in children has increased. The aim of this study was to identify changes in subject characteristics and endoscopic procedures during a 20-year interval in children undergoing EGD at a single center.All of the children undergoing first EGD with biopsy in 1985, 1995, or 2005 were identified. Details of the clinical presentation and EGD were abstracted from medical records in a random sample of subjects within each time point.The number of first-time EGDs rose dramatically from 107 in 1985 to 1294 in 2005. The proportion of subjects that were younger than 1 year of age varied significantly from 13% in 1985 to 23% in 1995 and 8% in 2005 (P < 0.001). The proportion of subjects with gastrointestinal (GI) bleeding declined from 34% to 5% during the 20-year interval (P < 0.001), whereas the proportion with abdominal pain increased from 23% to 43% (P < 0.01). During the same interval, the proportion of subjects with complete EGD (biopsies from the esophagus, stomach, and duodenum) increased from 18% of EGDs in 1985 to 95% in 2005 (P < 0.001).This study of children undergoing first-time EGDs with biopsy during a 20-year interval demonstrated significant differences in subject characteristics and endoscopy practices. The inclusion of children with less severe clinical presentation and the collection of greater numbers of biopsies per procedure may contribute to the rising incidence rates of pediatric GI disorders.

View details for DOI 10.1097/MPG.0b013e3181d67bee

View details for Web of Science ID 000282123600011

View details for PubMedID 20562722
Differences in Overnight Polysomnography Scores Using the Adult and Pediatric Criteria for Respiratory Events in Adolescents SLEEP Accardo, J. A., Shults, J., Leonard, M. B., Traylor, J., Marcus, C. L. 2010; 33 (10): 1333-1339
Abstract

There was no consensus in the 2007 American Academy of Sleep Medicine scoring manual on whether pediatric or adult respiratory criteria should be used in adolescents due to lack of data. Our objective was to compare pediatric and adult criteria in adolescents referred for obstructive sleep apnea (OSA). We hypothesized that pediatric criteria would capture more respiratory events than adult criteria.Retrospective cross-sectional analysis.Clinical sleep laboratory.101 subjects aged 13-18 years clinically referred for OSA.Overnight polysomnogram. Data were scored using both adult and pediatric AASM criteria. For adult criteria, data were scored using both AASM hypopnea rule A, defined by > or = 4% desaturation, and B, defined by > or = 3% desaturation or arousal.Median (range) apnea hypopnea index (AHI) by pediatric criteria was 1.7 events/hour (0-42.9). AHI using rule A was 0.4 (0-35.6); rule B, 1.4 (0-38.4). A higher pediatric AHI was associated with greater differences between pediatric and adult AHI using either rule A or B. There was no significant discordance in OSA classification comparing pediatric and adult criteria rule B (P = 0.3), but there was a significant rate of discordance classification comparing pediatric and adult criteria rule A(P < 0.001).Either pediatric or adult criteria rule B can be used in adolescents as few subjects change diagnostic category between these 2 criteria. Use of adult rule A results in fewer children meeting criteria for OSA. Further research into the clinical relevance of the scoring metric in adolescents is warranted.

View details for Web of Science ID 000282249700010

View details for PubMedID 21061855
Determinants of Changes in Linear Growth and Body Composition in Incident Pediatric Crohn's Disease GASTROENTEROLOGY Thayu, M., Denson, L. A., Shults, J., Zemel, B. S., Burnham, J. M., Baldassano, R. N., Howard, K. M., Ryan, A., Leonard, M. B. 2010; 139 (2): 430-438
Abstract

Pediatric Crohn's disease (CD) is associated with growth, lean mass (LM), and fat mass (FM) deficits. This study assessed and identified determinants of changes in height and body composition in children with CD following.Whole-body LM and FM were assessed using dual-energy x-ray absorptiometry in 78 CD subjects at diagnosis, 6, 12, and a median of 43 months (range, 24-63) later. Race- and sex-specific Z scores for lean mass (LM-ht-Z) and fat mass (FM-ht-Z) relative to height were derived using reference data in >900 controls. Serum cytokines and growth factors were measured, and quasi-least squares regression was used to identify determinants of changes in height and body composition.LM-ht-Z and FM-ht-Z (both P<.005) improved significantly after diagnosis; however, female patients had persistent LM deficits vs controls (-0.50+/-1.02, P<.05). Serum interleukin-6, tumor necrosis factor-alpha, and lipopolysaccharide binding protein decreased significantly (all P<.001). Greater increases in LM-ht-Z were associated with infliximab therapy (P<.05), increases in albumin (P<.001) and decreases in erythrocyte sedimentation rate (P<.05), interleukin-6 (P<.005), and lipopolysaccharide binding protein (P<.05). Greater increases in FM-ht-Z were associated with glucocorticoid, methotrexate, and infliximab therapy, and increases in albumin (P<.05) and growth hormone binding protein (P<.05). Overall, height-Z did not improve; however, greater increases in insulin-like growth factor-1 (P<.05) and decreases in tumor necrosis factor-alpha (P<.05), interleukin-6 (P<.05), and lipopolysaccharide binding protein (P<.05) levels were associated with increases in height-Z.Immune-mediated mechanisms contribute to growth and body composition deficits in CD. Therapies should target these deficits.

View details for DOI 10.1053/j.gastro.2010.04.044

View details for Web of Science ID 000280479100014

View details for PubMedID 20417635
Bone Mass and Microarchitecture in CKD Patients with Fracture JOURNAL OF THE AMERICAN SOCIETY OF NEPHROLOGY Nickolas, T. L., Stein, E., Cohen, A., Thomas, V., Staron, R. B., McMahon, D. J., Leonard, M. B., Shane, E. 2010; 21 (8): 1371-1380
Abstract

Patients with predialysis chronic kidney disease (CKD) have increased risk for fracture, but the structural mechanisms underlying this increased skeletal fragility are unknown. We measured areal bone mineral density (aBMD) by dual-energy x-ray absorptiometry at the spine, hip, and radius, and we measured volumetric BMD (vBMD), geometry, and microarchitecture by high-resolution peripheral quantitative computed tomography (HR-pQCT) at the radius and tibia in patients with CKD: 32 with fracture and 59 without fracture. Patients with fracture had lower aBMD at the spine, total hip, femoral neck, and the ultradistal radius, the last having the strongest association with fracture. By HR-pQCT of the radius, patients with fracture had lower cortical area and thickness, total and trabecular vBMD, and trabecular number and greater trabecular separation and network heterogeneity. At the tibia, patients with fracture had significantly lower cortical area, thickness, and total and cortical density. Total vBMD at both radius and tibia most strongly associated with fracture. By receiver operator characteristic curve analysis, patients with longer duration of CKD had area under the curve of >0.75 for aBMD at both hip sites and the ultradistal radius, vBMD and geometry at the radius and tibia, and microarchitecture at the tibia. In summary, patients with predialysis CKD and fractures have lower aBMD by dual-energy x-ray absorptiometry and lower vBMD, thinner cortices, and trabecular loss by HR-pQCT. These density and structural differences may underlie the increased susceptibility to fracture among patients with CKD.

View details for DOI 10.1681/ASN.2009121208

View details for Web of Science ID 000280746200023

View details for PubMedID 20395370
Pathologic Lower Extremity Fractures in Children With Alagille Syndrome JOURNAL OF PEDIATRIC GASTROENTEROLOGY AND NUTRITION Bales, C. B., Kamath, B. M., Munoz, P. S., Nguyen, A., Piccoli, D. A., Spinner, N. B., Horn, D., Shults, J., Leonard, M. B., Grimberg, A., Loomes, K. M. 2010; 51 (1): 66-70
Abstract

: In this retrospective study, we aimed to determine the incidence and distribution of fractures in patients with Alagille syndrome, 1 of the leading inherited causes of pediatric cholestatic liver disease.: Surveys regarding growth, nutrition, and organ involvement were distributed to patient families in the Alagille Syndrome Alliance of the Children's Hospital of Philadelphia research database. Patients with a history of fracture were identified by their response to 1 question, and details characterizing each patient's medical, growth, and fracture history were obtained through chart review and telephone contact.: Twelve of 42 patients (28%) reported a total of 27 fractures. Patients experienced fractures at a mean age of 5 years, which contrasts with healthy children, in whom fracture incidence peaks in adolescence. Fractures occurred primarily in the lower extremity long bones (70%) and with little or no trauma (84%). Estimated incidence rate calculations yielded 399.6 total fractures per 10,000 person-years (95% confidence interval 206.5, 698.0) and 127.6 femur fractures per 10,000 person-years (95% confidence interval 42.4, 297.7). There were no differences in sex, age distribution, or organ system involvement between the fracture and no-fracture groups.: Children with Alagille syndrome may be at risk for pathologic fractures, which manifest at an early age and in a unique distribution favoring the lower extremity long bones. Although this preliminary study is limited by small sample size and potential ascertainment bias, the data suggest that larger studies are warranted to further characterize fracture risk and explore factors contributing to bone fragility in these children.

View details for DOI 10.1097/MPG.0b013e3181cb9629

View details for Web of Science ID 000279160100013

View details for PubMedID 20453673
Effects of Sex, Race, and Puberty on Cortical Bone and the Functional Muscle Bone Unit in Children, Adolescents, and Young Adults JOURNAL OF CLINICAL ENDOCRINOLOGY & METABOLISM Leonard, M. B., Elmi, A., Mostoufi-Moab, S., Shults, J., Burnham, J. M., Thayu, M., Kibe, L., Wetzsteon, R. J., Zemel, B. S. 2010; 95 (4): 1681-1689
Abstract

Sex and race differences in bone development are associated with differences in growth, maturation, and body composition.The aim of the study was to determine the independent effects of sex, race, and puberty on cortical bone development and muscle-bone relations in children and young adults.We conducted a cross-sectional study of 665 healthy participants (310 male, 306 black) ages 5-35 yr.Tibia peripheral quantitative computed tomography measures were made of cortical bone mineral content (BMC) and bone mineral density (BMD), periosteal (Peri) and endosteal circumferences, section modulus (Zp), and muscle area. Regression models were adjusted for tibia length, age, race, sex, and Tanner stage.All cortical measures were greater in blacks than whites (all P < or = 0.001) in Tanner stages 1-4; however, differences in BMC, Peri, and Zp were negligible in Tanner stage 5 (all interactions, P < 0.01). Cortical BMC, Peri, and Zp were lower in females than males in all Tanner stages (all P < 0.001), and the sex differences in Peri and Zp were greater in Tanner stage 5 (interaction, P < 0.02). Cortical BMD was greater (P < 0.0001) and endosteal circumference was lower (P < 0.01) in Tanner 3-5 females, compared with males. Adjustment for muscle area attenuated but did not eliminate sex and race differences in cortical dimensions. Associations between muscle and bone outcomes did not differ according to sex or race.Sex and race were associated with maturation-specific differences in cortical BMD and dimensions that were not fully explained by differences in bone length or muscle. No race or sex differences in the functional muscle bone unit were identified.

View details for DOI 10.1210/jc.2009-1913

View details for Web of Science ID 000276402300025

View details for PubMedID 20157194
Height Adjustment in Assessing Dual Energy X-Ray Absorptiometry Measurements of Bone Mass and Density in Children JOURNAL OF CLINICAL ENDOCRINOLOGY & METABOLISM Zemel, B. S., Leonard, M. B., Kelly, A., Lappe, J. M., Gilsanz, V., Oberfield, S., Mahboubi, S., Shepherd, J. A., Hangartner, T. N., Frederick, M. M., Winer, K. K., Kalkwarf, H. J. 2010; 95 (3): 1265-1273
Abstract

In children, bone mineral content (BMC) and bone mineral density (BMD) measurements by dual-energy x-ray absorptiometry (DXA) are affected by height status. No consensus exists on how to adjust BMC or BMD (BMC/BMD) measurements for short or tall stature.The aim of this study was to compare various methods to adjust BMC/BMD for height in healthy children.Data from the Bone Mineral Density in Childhood Study (BMDCS) were used to develop adjustment methods that were validated using an independent cross-sectional sample of healthy children from the Reference Data Project (RDP).We conducted the study in five clinical centers in the United States.We included 1546 BMDCS and 650 RDP participants (7 to 17 yr of age, 50% female).No interventions were used.We measured spine and whole body (WB) BMC and BMD Z-scores for age (BMC/BMD(age)), height age (BMC/BMD(height age)), height (BMC(height)), bone mineral apparent density (BMAD(age)), and height-for-age Z-score (HAZ) (BMC/BMD(haz)).Spine and WB BMC/BMD(age)Z and BMAD(age)Z were positively (P < 0.005; r = 0.11 to 0.64) associated with HAZ. Spine BMD(haz) and BMC(haz)Z were not associated with HAZ; WB BMC(haz)Z was modestly associated with HAZ (r = 0.14; P = 0.0003). All other adjustment methods were negatively associated with HAZ (P < 0.005; r = -0.20 to -0.34). The deviation between adjusted and BMC/BMD(age) Z-scores was associated with age for most measures (P < 0.005) except for BMC/BMD(haz).Most methods to adjust BMC/BMD Z-scores for height were biased by age and/or HAZ. Adjustments using HAZ were least biased relative to HAZ and age and can be used to evaluate the effect of short or tall stature on BMC/BMD Z-scores.

View details for DOI 10.1210/jc.2009-2057

View details for Web of Science ID 000275197500034

View details for PubMedID 20103654
Official positions of the International Society for Clinical Densitometry (ISCD) on DXA evaluation in children and adolescents PEDIATRIC NEPHROLOGY Bianchi, M. L., Baim, S., Bishop, N. J., Gordon, C. M., Hans, D. B., Langman, C. B., Leonard, M. B., Kalkwarf, H. J. 2010; 25 (1): 37-47
Abstract

Dual-energy X-ray absorptiometry (DXA) is the most widely used technical instrument for evaluating bone mineral content (BMC) and density (BMD) in patients of all ages. However, its use in pediatric patients, during growth and development, poses a much more complex problem in terms of both the technical aspects and the interpretation of the results. For the adults population, there is a well-defined term of reference: the peak value of BMD attained by young healthy subjects at the end of skeletal growth. During childhood and adolescence, the comparison can be made only with healthy subjects of the same age, sex and ethnicity, but the situation is compounded by the wide individual variation in the process of skeletal growth (pubertal development, hormone action, body size and bone size). The International Society for Clinical Densitometry (ISCD) organized a Pediatric Position Development Conference to discuss the specific problems of bone densitometry in growing subjects (9-19 years of age) and to provide essential recommendations for its clinical use.

View details for DOI 10.1007/s00467-009-1249-z

View details for Web of Science ID 000271961000005

View details for PubMedID 19603190
Variation in Inpatient Therapy and Diagnostic Evaluation of Children with Henoch Schonlein Purpura JOURNAL OF PEDIATRICS Weiss, P. F., Klink, A. J., Hexem, K., Burnham, J. M., Leonard, M. B., Keren, R., Localio, R., Feudtner, C. 2009; 155 (6): 812-U272
View details for DOI 10.1016/j.jpeds.2009.05.030

View details for Web of Science ID 000209321900012
Variation in inpatient therapy and diagnostic evaluation of children with Henoch Schönlein purpura. journal of pediatrics Weiss, P. F., Klink, A. J., Hexem, K., Burnham, J. M., Leonard, M. B., Keren, R., Localio, R., Feudtner, C. 2009; 155 (6): 812-818 e1
Abstract

To describe variation regarding inpatient therapy and evaluation of children with Henoch Schönlein purpura (HSP) admitted to children's hospitals across the United States.We conducted a retrospective cohort study of children discharged with a diagnosis of HSP between 2000 and 2007 by use of inpatient administrative data from 36 children's hospitals. We examined variation among hospitals in the use of medications, diagnostic tests, and intensive care services with multivariate mixed effects logistic regression models.During the initial HSP hospitalization (n = 1988), corticosteroids were the most common medication (56% of cases), followed by opioids (36%), nonsteroidal antiinflammatory drugs (35%), and antihypertensive drugs (11%). After adjustment for patient characteristics, hospitals varied significantly in their use of corticosteroids, opioids, and nonsteroidal antiinflammatory drugs; the use of diagnostic abdominal imaging, endoscopy, laboratory testing, and renal biopsy; and the use of intensive care services. By contrast, hospitals did not differ significantly regarding administration of antihypertensive drugs or performance of skin biopsy.The significant variation identified may contribute to varying HSP clinical outcomes between hospitals, warrants further investigation, and represents a potentially important opportunity to improve quality of care.

View details for DOI 10.1016/j.jpeds.2009.05.030

View details for PubMedID 19643437
Serum Adiponectin Levels and Ambulatory Blood Pressure Monitoring in Pediatric Renal Transplant Recipients TRANSPLANTATION Sethna, C. B., Leonard, M. B., Gallagher, P. R., Meyers, K. E. 2009; 88 (8): 1030-1037
Abstract

BACKGROUND.: Reduced levels of serum adiponectin, an adipokine, are associated with cardiovascular and obesity-related diseases; however, relations between adiponectin and hypertension are unclear. METHODS.: This cross-sectional study examined adiponectin and ambulatory blood pressure monitoring (ABPM) in 33 pediatric renal transplant recipients (TXP), aged 8 to 19 years, median of 1.9 years after transplant. Serum total adiponectin (microg/mL) and high molecular weight-to-total adiponectin ratio (HMWr), 24-hr ABPM, and dual x-ray absorptiometry measures of fat mass were obtained. RESULTS.: The 12 TXP with hypertension (defined as BP index >1.0 and BP load >25%) had lower total adiponectin levels (7.4+/-3.2 vs. 10.9+/-5.2 microg/mL, P=0.045) compared with nonhypertensive TXP. Hypertensive TXP trended toward lower HMWr compared with nonhypertensive TXP (0.40+/-0.09 vs. 0.47+/-0.11, P=0.064). Levels did not differ according to sex, obesity or dipper status. In univariate analyses, total adiponectin and HMWr were negatively and significantly correlated with indexed BP in the daytime, nighttime, and 24-hr periods (R=-0.35 to -0.57). After adjustment for estimated glomerular filtration rate, fat mass, anti-hypertensive medication and fasting glucose, (1) lower total adiponectin was significantly and independently associated with greater elevations in all ABPM indexes except for nighttime systolic indexed BP, and (2) HMWr was inversely associated with all ABPM indexes. Lower adiponectin levels (P=0.049) and HMWr (P=0.042) were associated with greater odds of hypertension. CONCLUSION.: These data indicate that lower total adiponectin and HMWr were significantly and independently associated with greater ambulatory blood pressure.

View details for DOI 10.1097/TP.0b013e3181b9e1ec

View details for Web of Science ID 000271169700014

View details for PubMedID 19855250
Viral hepatitis is associated with reduced bone mineral density in HIV-infected women but not men 16th Conference on Retroviruses and Opportunistic Infections (CROI) Lo Re, V., Guaraldi, G., Leonard, M. B., Localio, A. R., Lin, J., Orlando, G., Zirilli, L., Rochira, V., Kostman, J. R., Tebas, P. LIPPINCOTT WILLIAMS & WILKINS. 2009: 2191–98
Abstract

Few studies have examined the impact of viral hepatitis on bone mineral density (BMD), and none have done so among HIV-infected patients. Our objective was to determine whether viral hepatitis was associated with low BMD in HIV.: A cross-sectional study among 1237 HIV-infected patients (625 with viral hepatitis).Dual-energy X-ray absorptiometry scans of the lumbar spine and femoral neck were obtained. Clinical data, hepatitis B and C status, and markers of bone metabolism were determined at dual-energy X-ray absorptiometry scanning. Multivariable logistic regression examined the association between hepatitis and low BMD (Z-score < or =-2.0 at the lumbar spine, femoral neck, or both).Mean BMD Z-scores were lower among hepatitis-coinfected women at the lumbar spine {-0.15 versus +0.29; difference = -0.44 [95% confidence Interval (CI) -0.65 to -0.23]; P < 0.001} and femoral neck [-0.64 versus -0.39; difference = -0.25 (95% CI -0.44 to -0.06); P = 0.009] compared with HIV-monoinfected women. No differences in mean BMD Z-scores were observed between coinfected and monoinfected men. After adjustment for age, BMI, duration of HIV, antiretroviral use, physical activity, and smoking, viral hepatitis was associated with low BMD among women (adjusted odds ratio 2.87, 95% CI 1.31-6.29) but not men (adjusted odds ratio 1.19, 95% CI 0.74-1.91). Coinfected women had lower mean parathyroid hormone (60.1 versus 68.1 pg/ml; P = 0.02) but similar mean 25-hydroxyvitamin D (19.1 versus 19.6 ng/ml; P = 0.6) and osteocalcin (3.0 versus 3.2 ng/ml; P = 0.8) concentrations than HIV-monoinfected women.Viral hepatitis was associated with a higher risk of low BMD among HIV-infected women but not men.

View details for DOI 10.1097/QAD.0b013e32832ec258

View details for Web of Science ID 000271599200015

View details for PubMedID 19779322
Cardiorespiratory Fitness in Pediatric Renal Transplant Recipients TRANSPLANTATION Sethna, C. B., Salerno, A. E., McBride, M. G., Shults, J., Paridon, S. M., Sharma, N., Meyers, K. E., Leonard, M. B. 2009; 88 (3): 395-401
Abstract

The impact of body size, fat-free mass (FFM), and fat mass (FM) on cardiorespiratory fitness in pediatric renal transplant recipients (TX) has not been established. Study objectives were to assess maximal oxygen consumption (VO2max) in TX and controls, adjusted for body composition, and to identify risk factors for reduced fitness in TX.Cycle ergometry and dual-energy X-ray absorptiometry were obtained in 50 TX and 70 controls, ages 8 to 21 years. Control recruitment was targeted to include obese subjects with body mass index Z-scores comparable with TX. Allometric regression models were used.TX had significantly lower height Z-scores (P<0.001) and comparable body mass index Z-scores. VO2max per body weight (mL/kg/min) and per FFM (mL/kgFFM/min) did not differ between groups. However, VO2max was 13% lower (95% CI 18, 8; P<0.001) in TX, compared with controls, adjusted for FM, FFM, sex, and race. Greater FFM, lower FM, non-black race, and male sex were independently associated with greater VO2max. Within TX, hemoglobin levels were positively associated with VO2max (P=0.04) and sirolimus use was associated with lower VO2max (P<0.01).TX had significant VO2max deficits that were not captured by conventional measures (mL/kg/min). Greater FM was an independent risk factor for low VO2max. Lower fitness in TX may be related to sirolimus effects on skeletal muscle.

View details for DOI 10.1097/TP.0b013e3181aed7d1

View details for Web of Science ID 000268940000018

View details for PubMedID 19667944
Hypovitaminosis D is Associated with Greater Body Mass Index and Disease Activity in Pediatric Systemic Lupus Erythematosus JOURNAL OF PEDIATRICS Wright, T. B., Shults, J., Leonard, M. B., Zemel, B. S., Burnham, J. M. 2009; 155 (2): 260-265
Abstract

To determine whether pediatric systemic lupus erythematosus (SLE) is associated with alterations in the vitamin D-parathyroid hormone (PTH) axis and to assess the relation between vitamin D deficiency and SLE activity.25-hydroxy vitamin D [25(OH)D], 1,25-dihydroxy vitamin D [1,25(OH)2D], and intact PTH were measured in subjects with SLE (n = 38) and healthy controls (n = 207), ages 5 to 21 years. Vitamin D status and its relation with disease activity were assessed using multivariable logistic and linear regression.Severe vitamin D deficiency (25(OH)D <10 ng/ml) was observed in a significantly higher proportion of subjects with SLE (36.8% vs 9.2%, P < .001). In SLE, the odds ratio (OR) for severe deficiency was 2.37 (P = .09), adjusting for age, sex, race, and season. However, for each 1 SD greater body mass index (BMI) z-score, 25(OH)D levels were 4.2 ng/mL lower (P = .01) in SLE, compared with controls. Adjusting for 25(OH)D levels, SLE was associated with significantly lower 1,25(OH)2D (P < .001) and intact PTH levels (P = .03). Greater SLE disease activity index scores were observed in those with 25(OH)D <20 ng/mL (P = .01).SLE was associated with vitamin D deficiency, particularly among those subjects with SLE who were overweight. Future studies should assess the effect of vitamin D supplementation on skeletal and nonskeletal outcomes in SLE.

View details for DOI 10.1016/j.jpeds.2009.02.033

View details for Web of Science ID 000268781200026

View details for PubMedID 19446841
Revised Pediatric Reference Data for the Lateral Distal Femur Measured by Hologic Discovery/Delphi Dual-Energy X-Ray Absorptiometry JOURNAL OF CLINICAL DENSITOMETRY Zemel, B. S., Stallings, V. A., Leonard, M. B., Paulhamus, D. R., Kecskemethy, H. H., Harcke, H. T., Henderson, R. C. 2009; 12 (2): 207-218
Abstract

Lateral distal femur (LDF) scans by dual-energy X-ray absorptiometry (DXA) are often feasible in children for whom other sites are not measurable. Pediatric reference data for LDF are not available for more recent DXA technology. The objective of this study was to assess older pediatric LDF reference data, construct new reference curves for LDF bone mineral density (BMD), and demonstrate the comparability of LDF BMD to other measures of BMD and strength assessed by DXA and by peripheral quantitative computed tomography (pQCT). LDF, spine and whole body scans of 821 healthy children, 5-18 yr of age, recruited at a single center were obtained using a Hologic Discovery/Delphi system (Hologic, Inc., Bedford, MA). Tibia trabecular and total BMD (3% site), cortical geometry (38% site) (cortical thickness, section modulus, and strain-strength index) were assessed by pQCT. Sex- and race-specific reference curves were generated using LMS Chartmaker (LMS Chartmaker Pro, version 2.3. Tim Cole and Huiqi Pan. Copyright 1997-2006, Medical Research Council, UK) and Z-scores calculated and compared by correlation analysis. Z-scores for LDF BMD based on published findings demonstrated overestimation or underestimation of the prevalence of low BMD-for-age depending on the region of interest considered. Revised LDF reference curves were generated. The new LDF Z-scores were strongly and significantly associated with weight, body mass index, spine and whole body BMD Z-scores, and all pQCT Z-scores. These findings demonstrate the comparability of LDF measurements to other clinical and research bone density assessment modes, and enable assessment of BMD in children with disabilities, who are particularly prone to low trauma fractures of long bones, and for whom traditional DXA measurement sites are not feasible.

View details for DOI 10.1016/j.jocd.2009.01.005

View details for Web of Science ID 000266251100009

View details for PubMedID 19321369
Divergent Effects of Glucocorticoids on Cortical and Trabecular Compartment BMD in Childhood Nephrotic Syndrome JOURNAL OF BONE AND MINERAL RESEARCH Wetzsteon, R. J., Shults, J., Zemel, B. S., Gupta, P. U., Burnham, J. M., Herskovitz, R. M., Howard, K. M., Leonard, M. B. 2009; 24 (3): 503-513
Abstract

Glucocorticoid (GC) effects on skeletal development have not been established. The objective of this pQCT study was to assess volumetric BMD (vBMD) and cortical dimensions in childhood steroid-sensitive nephrotic syndrome (SSNS), a disorder with minimal independent deleterious skeletal effects. Tibia pQCT was used to assess trabecular and cortical vBMD, cortical dimensions, and muscle area in 55 SSNS (age, 5-19 yr) and >650 control participants. Race-, sex-, and age-, or tibia length-specific Z-scores were generated for pQCT outcomes. Bone biomarkers included bone-specific alkaline phosphatase and urinary deoxypyridinoline. SSNS participants had lower height Z-scores (p < 0.0001) compared with controls. In SSNS, Z-scores for cortical area were greater (+0.37; 95% CI = 0.09, 0.66; p = 0.01), for cortical vBMD were greater (+1.17; 95% CI = 0.89, 1.45; p < 0.0001), and for trabecular vBMD were lower (-0.60; 95% CI, = -0.89, -0.31; p < 0.0001) compared with controls. Muscle area (+0.34; 95% CI = 0.08, 0.61; p = 0.01) and fat area (+0.56; 95% CI = 0.27, 0.84; p < 0.001) Z-scores were greater in SSNS, and adjustment for muscle area eliminated the greater cortical area in SSNS. Bone formation and resorption biomarkers were significantly and inversely associated with cortical vBMD in SSNS and controls and were significantly lower in the 34 SSNS participants taking GCs at the time of the study compared with controls. In conclusion, GCs in SSNS were associated with significantly greater cortical vBMD and cortical area and lower trabecular vBMD, with evidence of low bone turnover. Lower bone biomarkers were associated with greater cortical vBMD. Studies are needed to determine the fracture implications of these varied effects.

View details for DOI 10.1359/JBMR.081101

View details for Web of Science ID 000263572100014

View details for PubMedID 19016583
A Structural Approach to Skeletal Fragility in Chronic Kidney Disease SEMINARS IN NEPHROLOGY Leonard, M. B. 2009; 29 (2): 133-143
Abstract

Renal osteodystrophy is a multifactorial disorder of bone metabolism in chronic kidney disease (CKD). As CKD progresses, ensuing abnormalities in mineral metabolism result in distortions in trabecular microarchitecture, thinning of the cortical shell, and increased cortical porosity. Recent studies have shown significantly increased hip fracture rates in CKD stages 3 and 4, in dialysis patients, and in transplant recipients. The majority of studies of bone loss in CKD relied on dual-energy x-ray absorptiometry (DXA) measures of bone mineral density. However, DXA summarizes the total bone mass within the projected bone area, concealing distinct structural alterations in trabecular and cortical bone. Recent data have confirmed that peripheral quantitative computed tomography (pQCT) measures of cortical density and thickness provide substantially better fracture discrimination in dialysis patients, compared with hip or spine DXA. This review summarizes the growing evidence for bone fragility in CKD stages 3 through 5, considers the effects of CKD on trabecular and cortical bone structure as it relates to fracture risk, and details the potential advantages and disadvantages of DXA and alternative measures of bone density, geometry, and microarchitecture, including pQCT, high-resolution pQCT, and micro-magnetic resonance imaging for fracture risk assessment in CKD.

View details for DOI 10.1016/j.semnephrol.2009.01.006

View details for Web of Science ID 000265459400006

View details for PubMedID 19371804
A Note on the Use of Unbiased Estimating Equations to Estimate Correlation in Analysis of Longitudinal Trials BIOMETRICAL JOURNAL Sun, W., Shults, J., Leonard, M. 2009; 51 (1): 5-18
Abstract

Longitudinal trials can yield outcomes that are continuous, binary (yes/no), or are realizations of counts. In this setting we compare three approaches that have been proposed for estimation of the correlation in the framework of generalized estimating equations (GEE): quasi-least squares (QLS), pseudo-likelihood (PL), and an approach we refer to as Wang-Carey (WC). We prove that WC and QLS are identical for the first-order autoregressive AR(1) correlation structure. Using simulations, we then develop guidelines for selection of an appropriate method for analysis of data from a longitudinal trial. In particular, we argue that no method is uniformly superior for analysis of unbalanced and unequally spaced data with a Markov correlation structure. Choice of the best approach will depend on the degree of imbalance and variability in the temporal spacing of measurements, value of the correlation, and type of outcome, e.g. binary or continuous. Finally, we contrast the methods in analysis of a longitudinal study of obesity following renal transplantation in children.

View details for DOI 10.1002/bimj.200710493

View details for Web of Science ID 000264082000001

View details for PubMedID 19197953
Serum Alkaline Phosphatase Reflects Post-Fontan Hemodynamics in Children PEDIATRIC CARDIOLOGY Chin, A. J., Stephens, P., Goldmuntz, E., Leonard, M. B. 2009; 30 (2): 138-145
Abstract

Although survivors of Fontan palliation for a single ventricle are known to have lower cardiac index than patients with two-ventricle surgical reconstructions, it is unclear whether two frequently observed sequelae, short stature and protein-losing enteropathy (PLE), have hemodynamic origins. A serum marker that reflects hemodynamic status would be a tremendous asset in the long-term management of children with these sequelae. The authors recently noted severely reduced total alkaline phosphatase (TALP) levels in two children with early-onset PLE after Fontan operations, both of whom had low cardiac output at cardiac catheterization. Catheter-based or surgical interventions that rapidly increased cardiac output in these two patients resulted not only in relief of PLE but also in a prompt TALP rise. To examine whether the apparent correlation of low TALP with impaired cardiac output also is seen in Fontan patients without PLE, this study retrospectively examined the TALP data from two other Fontan patients who underwent cardiac catheterization specifically to assess the potential benefit of vasodilator therapy. The TALP levels were abnormally low in both cases but increased after up-titration of angiotensin-converting enzyme inhibition. Serum TALP activity, an indicator of osteoblastic function particularly in pre-adolescence, may be a marker of low cardiac output after a Fontan operation.

View details for DOI 10.1007/s00246-008-9292-2

View details for Web of Science ID 000263097500008

View details for PubMedID 18685798
Retrospective 3D Registration of Trabecular Bone MR Images for Longitudinal Studies JOURNAL OF MAGNETIC RESONANCE IMAGING Magland, J. F., Jones, C. E., Leonard, M. B., Wehrli, F. W. 2009; 29 (1): 118-126
Abstract

To evaluate an automatic 3D registration algorithm for serial high-resolution images of trabecular bone (TB) in studies designed to evaluate the response of the trabecular architecture to intervention or disease progression.An efficient algorithm for registering high-resolution 3D images of TB is presented. The procedure identifies the six parameters of rigid displacement between two scans performed at different timepoints. By assuming a relatively small through-plane rotation, considerable time is saved by combining the results of a collection of regional 2D registrations throughout the TB region of interest (ROI). The algorithm was applied to 26 pairs of MR images acquired 6 months apart. Reproducibility of local TB structural parameters (plate, rod, and junction density) computed in manually selected regions were compared between baseline and registered follow-up images.All 26 registrations were completed successfully in less than 30 seconds per image pair. The resampled follow-up images agreed with baseline to around one pixel throughout the volume at 137 x 137 x 410 microm(3) image resolution. Structural parameters in each region correlated well from baseline to follow-up with intraclass correlation coefficients ranging between 85%-97% for TB plate density. Interregional variations in the parameters were large as compared with intraregion reproducibility.The proposed algorithm was successful in automatically registering baseline and follow-up TB images in a translational study, and may be useful in regional analyses in longitudinal MR studies of TB architecture.

View details for DOI 10.1002/jmri.21551

View details for Web of Science ID 000262168200015

View details for PubMedID 19097098
Bone Health in a Nonjaundiced Population of Children with Biliary Atresia GASTROENTEROLOGY RESEARCH AND PRACTICE Kramer, R. A., Zemel, B. S., Arvay-Nezu, J. L., Stallings, V. A., Leonard, M. B., Haber, B. A. 2009
Abstract

To assess bone health in a cohort of nonjaundiced children with biliary atresia (BA) and the effect of growth and development on bone outcomes.Children ages one to eighteen years receiving care from Children's Hospital of Philadelphia were recruited. Each child was seen once and assessed for growth, pubertal development, concurrent medications, bilirubin, ALT, albumin, vitamin D status, bone mineral density (BMD), and bone mineral content (BMC) of the lumbar spine and whole body.BMD declined significantly with age, and upon further analysis with a well-phenotyped control cohort, it was found that BMC was significantly decreased for both lumbar spine and whole body, even after adjustment for confounding variables. An age interaction was identified, with older subjects having a significantly greater impairment in BMC.These preliminary results demonstrate that children with BA, including those without jaundice, are likely to have compromised bone health even when accounting for height and puberty, which are common confounding factors in chronic disease. Further investigation is needed to identify the determinants of poor bone mineral status and to develop strategies to prevent osteoporosis later in life.

View details for DOI 10.1155/2009/387029

View details for Web of Science ID 000284907400001

View details for PubMedID 19606216
Longitudinal Assessment of Bone Density and Structure in an Incident Cohort of Children With Crohn's Disease GASTROENTEROLOGY Dubner, S. E., Shults, J., Baldassano, R. N., Zemel, B. S., Thayu, M., Burnham, J. M., Herskovitz, R. M., Howard, K. M., Leonarda, M. B. 2009; 136 (1): 123-130
Abstract

The impact of childhood Crohn's disease (CD) on volumetric bone mineral density (vBMD), bone structure, and muscle mass have not been established. The objective of this longitudinal study was to assess musculoskeletal outcomes in an incident cohort of children with CD using peripheral quantitative computed tomography (pQCT).Tibia pQCT was performed in 78 CD subjects (ages, 5-18 years) at diagnosis and in 67 over the subsequent year. pQCT outcomes were converted to sex- and race-specific z scores based on reference data in over 650 controls. Multivariable linear regression models identified factors associated with changes in bone outcomes.At diagnosis, CD subjects had significant deficits in trabecular vBMD (z score, -1.32+/-1.32; P< .001), cortical section modulus (a measure of bone geometry and strength) (z score, -0.44+/-1.11; P< .01), and muscle (z score, -0.96+/-1.02; P< .001) compared with controls. Over the first 6 months, trabecular vBMD and muscle z scores improved significantly (both, P< .001); however, section modulus worsened (P= .0001), and all 3 parameters remained low after 1 year. Increases in muscle z scores were associated with less severe declines in cortical section modulus z scores. Improvements in trabecular vBMD z scores were greater in prepubertal subjects. Glucocorticoids were associated with increases in cortical vBMD.Substantial deficits in trabecular vBMD, cortical bone geometry, and muscle were observed at CD diagnosis. Trabecular vBMD improved incompletely; however, cortical deficits progressed despite improvements in muscle. Glucocorticoids were not associated with bone loss. Therapies to improve bone accrual in childhood CD are needed.

View details for DOI 10.1053/j.gastro.2008.09.072

View details for Web of Science ID 000262028500020

View details for PubMedID 19026647
Association of Serum Intact Parathyroid Hormone with Lower Estimated Glomerular Filtration Rate CLINICAL JOURNAL OF THE AMERICAN SOCIETY OF NEPHROLOGY Muntner, P., Jones, T. M., Hyre, A. D., Melamed, M. L., Alper, A., Raggi, P., Leonard, M. B. 2009; 4 (1): 186-194
Abstract

The prevalence of mineral metabolism abnormalities is almost universal in stage 5 chronic kidney disease (CKD), but the presence of abnormalities in milder CKD is not well characterized.Data on adults > or =20 yr of age from the National Health and Nutrition Examination Survey 2003-2004 (N = 3949) were analyzed to determine the association between moderate declines in estimated GFR (eGFR), calculated using the Modfication of Diet in Renal Disease formula, and serum intact parathyroid hormone (iPTH) > or = 70 pg/ml.The geometric mean iPTH level was 39.3 pg/ml. The age-standardized prevalence of elevated iPTH was 8.2%, 19.3%, and 38.3% for participants with eGFR > or = 60, 45 to 59, and 30 to 44 ml/min/1.73 m(2), respectively (P-trend < 0.001). After adjustment for age; race/ethnicity; sex; menopausal status; education; income; cigarette smoking; alcohol consumption; body mass index; hypertension; diabetes mellitus; vitamin D supplement use; total calorie and calcium intake; and serum calcium, phosphorus, and 25-hydroxyvitamin D levels-and compared with their counterparts with an eGFR > or = 60 ml/min/1.73 m(2)-the prevalence ratios of elevated iPTH were 2.30 and 4.69 for participants with an eGFR of 45 to 59 and 30 to 44 ml/min/1.73 m(2), respectively (P-trend < 0.001). Serum phosphorus > or = 4.2 mg/dl and 25-hydroxyvitamin D < 17.6 ng/ml were more common at lower eGFR levels. No association was present between lower eGFR and serum calcium < 9.4 mg/dl.This study indicates that elevated iPTH levels are common among patients with moderate CKD.

View details for DOI 10.2215/CJN.03050608

View details for Web of Science ID 000262681200028

View details for PubMedID 19019998
Improvement in Biomarkers of Bone Formation During Infliximab Therapy in Pediatric Crohn's Disease: Results of the REACH Study CLINICAL GASTROENTEROLOGY AND HEPATOLOGY Thayu, M., Leonard, M. B., Hyams, J. S., Crandall, W. V., Kugathasan, S., Otley, A. R., Olson, A., Johanns, J., Marano, C. W., Heuschkel, R. B., Veereman-Wauters, G., Griffiths, A. M., Baldassano, R. N. 2008; 6 (12): 1378-1384
Abstract

Crohn's disease (CD) is associated with altered bone metabolism. This study examined changes in bone formation and resorption after infliximab induction and associations between bone biomarkers, linear growth, and disease activity (Pediatric Crohn's Disease Activity Index [PCDAI]) after 54 weeks of infliximab therapy.One hundred twelve subjects ages 6-17 years with moderate to severe CD received infliximab induction (5 mg/kg/dose) at weeks 0, 2, and 6; week-10 responders were randomized to infliximab every 8 or every 12 weeks maintenance therapy. Serum bone-specific alkaline phosphatase (BSAP), N-terminal propeptide of type 1 collagen (P1NP), urine C-telopeptide of collagen cross-links (CTX-1), and deoxypyrodinoline (DPD) were collected at baseline and 10 weeks. PCDAI and height z-scores were assessed at baseline and at 10 and 54 weeks.Models were adjusted for bone age, gender, height, and steroid use. Baseline BSAP and P1NP levels were negatively associated with PCDAI (both P = .01). BSAP and P1NP increased during induction (both P < .001) and were associated with 54-week increases in height z-score (P < .05 and P < .001, respectively). Improvements in P1NP were associated with 54-week decreases in PCDAI (P = .01). CTX-1 and DPD also increased during induction (P < .001 and P = .01, respectively) but were not associated with changes in PCDAI. Changes in CTX-1 were associated with improvements in height z-score (P < .002).Infliximab therapy is associated with dramatic increases in BSAP and P1NP, consistent with inhibition of tumor necrosis factor-alpha effects on osteoblasts. The increases in CTX-1 and DPD likely reflect coupling of bone formation and resorption and increases in linear growth.

View details for DOI 10.1016/j.cgh.2008.07.010

View details for Web of Science ID 000261724300015

View details for PubMedID 19081527
International Society for Clinical Densitometry 2007 Adult and Pediatric Official Positions BONE Lewiecki, E. M., Gordon, C. M., Baim, S., Leonard, M. B., Bishop, N. J., Bianchi, M., Kalkwarf, H. J., Langman, C. B., Plotkin, H., Rauch, F., Zemel, B. S., Binkley, N., Bilezikian, J. P., Kendler, D. L., Hans, D. B., Silverman, S. 2008; 43 (6): 1115-1121
Abstract

The International Society for Clinical Densitometry (ISCD) periodically convenes Position Development Conferences (PDCs) in order to establish standards and guidelines for the assessment of skeletal health. The most recent Adult PDC was held July 20-22, 2007, in Lansdowne, Virginia, USA; the first Pediatric PDC was June 20-21, 2007 in Montreal, Quebec, Canada. PDC topics were selected according to clinical relevancy, perceived need for standardization, and likelihood of achieving agreement. Each topic area was assigned to a task force for a comprehensive review of the scientific literature. The findings of the review and recommendations were presented to adult and pediatric international panels of experts. The panels voted on the appropriateness, necessity, quality of the evidence, strength, and applicability (worldwide or variable according to local requirements) of each recommendation. Those recommendations that were approved by the ISCD Board of Directors become Official Positions. This is a review of the methodology of the PDCs and selected ISCD Official Positions.

View details for DOI 10.1016/j.bone.2008.08.106

View details for Web of Science ID 000261825900020

View details for PubMedID 18793764
Interpretation of Biomarkers of Bone Metabolism in Children: Impact of Growth Velocity and Body Size in Healthy Children and Chronic Disease JOURNAL OF PEDIATRICS Tuchman, S., Thayu, M., Shults, J., Zemel, B. S., Burnham, J. M., Leonard, M. B. 2008; 153 (4): 484-490
Abstract

To determine the effects of growth, maturation, and whole body bone mineral content (WB-BMC) accrual on biomarkers of bone formation (bone-specific alkaline phosphatase [BSAP]) and resorption (urine deoxypyridinoline/creatinine [DPD]) in healthy children and children with Crohn's disease.BSAP and DPD were measured at baseline, with growth and dual energy x-ray absorptiometry (DXA) WB-BMC measured at baseline and 6 months in 202 control subjects and 110 subjects with Crohn's disease, ages 5 to 21 years. Multivariable linear regression identified determinants of biomarkers in control subjects and subjects with Crohn's disease.In control subjects, BSAP and DPD were significantly and independently associated with sex, Tanner stage, WB-BMC, height velocity, and WB-BMC accrual rates; these covariates explained 77% to 80% of the variability in the bone biomarkers, respectively. Subjects with Crohn's disease had lower height-for-age (P < .001) and WB-BMC-for-height (P <.05) than control subjects. Crohn's disease was associated with lower BSAP (P < .001) and greater DPD (P < .001), independent of growth, maturation, baseline WB-BMC, and WB-BMC accrual, compared with control subjects.These data illustrate the potential confounding effects of growth and WB-BMC on bone metabolism biomarkers in children. After adjustment for these effects, Crohn's disease was associated with lower biomarkers of bone formation and greater bone resorption.

View details for DOI 10.1016/j.jpeds.2008.04.028

View details for Web of Science ID 000260101600011

View details for PubMedID 18555484
Special report on the 2007 adult and pediatric Position Development Conferences of the International Society for Clinical Densitometry OSTEOPOROSIS INTERNATIONAL Lewiecki, E. M., Gordon, C. M., Baim, S., Binkley, N., Bilezikian, J. P., Kendler, D. L., Hans, D. B., Silverman, S., Bishop, N. J., Leonard, M. B., Bianchi, M., Kalkwarf, H. J., Langman, C. B., Plotkin, H., Rauch, F., Zemel, B. S. 2008; 19 (10): 1369-1378
Abstract

The International Society for Clinical Densitometry (ISCD) conducts Position Development Conferences (PDCs) for the purpose of establishing standards and guidelines in the field of bone densitometry. Topics for consideration are selected according to clinical relevance, a perceived need for standardization, and the likelihood of achieving agreement. Questions regarding nomenclature, indications, acquisition, analysis, quality control, interpretation, and reporting of bone density tests for each topic area are assigned to task forces for a comprehensive review of the scientific literature. The findings of the review and recommendations are then presented to an international panel of experts at the PDC. The expert panel votes on potential Official Positions for appropriateness, necessity, quality of the evidence, strength of the recommendation, and applicability (worldwide or variable according to local requirements). Recommendations that are approved by the ISCD Board of Directors become Official Positions. The first Pediatric PDC was 20-21 June 2007 in Montreal, QC, Canada. The most recent Adult PDC was held 20-22 July 2007, in Lansdowne, VA, USA. This Special Report summarizes the methodology of the ISCD PDCs and presents selected Official Positions of general interest.

View details for DOI 10.1007/s00198-008-0689-9

View details for Web of Science ID 000259820100002

View details for PubMedID 18633664
Chronic kidney disease and bone fracture: a growing concern KIDNEY INTERNATIONAL Nickolas, T. L., Leonard, M. B., Shane, E. 2008; 74 (6): 721-731
Abstract

Susceptibility to fracture is increased across the spectrum of chronic kidney disease (CKD). Moreover, fracture in patients with end-stage kidney disease (ESKD) results in significant excess mortality. The incidence and prevalence of CKD and ESKD are predicted to increase markedly over the coming decades in conjunction with the aging of the population. Given the high prevalence of both osteoporosis and CKD in older adults, it is of the utmost public health relevance to be able to assess fracture risk in this population. Dual-energy X-ray absorptiometry (DXA), which provides an areal measurement of bone mineral density (aBMD), is the clinical standard to predict fracture in individuals with postmenopausal or age-related osteoporosis. Unfortunately, DXA does not discriminate fracture status in patients with ESKD. This may be, in part, because excess parathyroid hormone (PTH) secretion may accompany declining kidney function. Chronic exposure to high PTH levels preferentially causes cortical bone loss, which may be partially offset by periosteal expansion. DXA can neither reliably detect changes in bone volume nor distinguish between trabecular and cortical bone. In addition, DXA measurements may be low, normal, or high in each of the major forms of renal osteodystrophy (ROD). Moreover, postmenopausal or age-related osteoporosis may also affect patients with CKD and ESKD. Currently, transiliac crest bone biopsy is the gold standard to diagnose ROD and osteoporosis in patients with significant kidney dysfunction. However, bone biopsy is an invasive procedure that requires time-consuming analyses. Therefore, there is great interest in developing non-invasive high-resolution imaging techniques that can improve fracture risk prediction for patients with CKD. In this paper, we review studies of fracture risk in the setting of ESKD and CKD, the pathophysiology of increased fracture risk in patients with kidney dysfunction, the utility of various imaging modalities in predicting fracture across the spectrum of CKD, and studies evaluating the use of bisphosphonates in patients with CKD.

View details for DOI 10.1038/ki.2008.264

View details for Web of Science ID 000258874600008

View details for PubMedID 18563052
Status of bone mineral density in patients selected for cardiac transplantation. Endocrine practice Iqbal, N., Ducharme, J., Desai, S., Chambers, S., Terembula, K., Chan, G. W., Shults, J., Leonard, M. B., Kumanyika, S. 2008; 14 (6): 704-712
Abstract

To determine the prevalence and correlates of low bone mineral density (BMD) in ambulatory outpatients with end-stage heart failure who were awaiting cardiac transplantation.Fifty-five cardiac transplant candidates with end-stage heart failure were enrolled in this study. Bone mineral density at the lumbar spine and proximal femur was determined by dual-energy x-ray absorptiometry. Laboratory studies included serum alkaline phosphatase, calcium, intact parathyroid hormone, and 25-hydroxyvitamin D.The mean proximal femur and lumbar spine Z scores were 0.3 +/- 1.1 and 0.3 +/- 1.5, respectively. The mean BMD was not lower than that of the age-and sex-matched reference population. Z scores were less than -1 in 23% at the lumbar spine and 15% at the proximal femoral neck. On the basis of T scores, osteopenia (T scores between -1 and -2.5) was present in 24% (confidence interval, 13% to 35%) of patients at the lumbar spine and in 20% (confidence interval, 10% to 30%) at the proximal femur; osteoporosis (T scores of less than -2.5) was present in 4% of the study population. Half of the patients in this study sample had elevated intact parathyroid hormone levels, and a third of the patients had low 25-hydroxyvitamin D levels.Lumbar spine and hip BMD measurements were not significantly low relative to age and sex in ambulatory patients with heart failure awaiting cardiac transplantation.

View details for PubMedID 18996789
Cortical bone water: In vivo quantification with ultrashort echo-time MR imaging RADIOLOGY Techawiboonwong, A., Song, H. K., Leonard, M. B., Wehrli, F. W. 2008; 248 (3): 824-833
Abstract

To develop and evaluate a method based on ultrashort echo-time radial magnetic resonance (MR) imaging to quantify bone water (BW) concentration as a new metric of bone quality in human cortical bone in vivo.Human subject studies were institutional review board approved and HIPAA compliant; informed consent was obtained. Cortical BW concentration was determined with custom-designed MR imaging sequences at 3.0 T and was validated in sheep and human cortical bone by using exchange of native water with deuterium oxide (D(2)O). The submillisecond T2* of BW requires correction for relaxation losses during the radiofrequency pulse. BW was measured at the tibial midshaft in healthy pre- and postmenopausal women (mean age, 34.6 and 69.4 years, respectively; n = 5 in each group) and in patients receiving maintenance hemodialysis (mean age, 51.8 years; n = 6) and was compared with bone mineral density (BMD) at the same site at peripheral quantitative computed tomography, as well as with BMD of the lumbar spine and hip at dual x-ray absorptiometry. Data were analyzed by using the Pearson correlation coefficient and two-sided t tests as appropriate.Excellent agreement was obtained ex vivo between the water displaced by using D(2)O exchange and water measured with respect to a reference sample (r(2) = 0.99, P < .001). In vivo, BW in the postmenopausal group was greater by 65% (28.7% +/- 1.3 [standard deviation] vs 17.4% +/- 2.2, P < .001) than in the premenopausal group, and patients with renal osteodystrophy had higher BW (41.4% +/- 9.6) than the premenopausal group by 135% (P < .001) and the postmenopausal group by 43% (P = .02). BMD showed an opposite behavior, with much smaller group differences. Because the majority of BW is in the pore system of cortical bone, this parameter provides a surrogate measure for cortical porosity.A new MR imaging-based method for quantifying BW noninvasively has been demonstrated.

View details for DOI 10.1148/radiol.2482071995

View details for Web of Science ID 000258541500018

View details for PubMedID 18632530
Bone density, structure, and strength in juvenile idiopathic arthritis ARTHRITIS AND RHEUMATISM Burnham, J. M., Shults, J., Dubner, S. E., Sembhi, H., Zemel, B. S., Leonard, M. B. 2008; 58 (8): 2518-2527
Abstract

To identify determinants of musculoskeletal deficits (muscle cross-sectional area [mCSA], trabecular volumetric bone mineral density [vBMD], and cortical bone strength [section modulus]) in patients with juvenile idiopathic arthritis (JIA) and to determine if cortical bone strength is appropriately adapted to muscle forces.Peripheral quantitative computed tomography (pQCT) of the tibia was performed in 101 patients with JIA (79% female; 24 with oligoarticular JIA, 40 with polyarticular JIA, 18 with systemic JIA, and 19 with spondylarthritis [SpA]) and 830 healthy control subjects; all were ages 5-22 years. Outcomes of pQCT were expressed as sex- and race-specific Z scores. Multivariable linear regression models assessed mCSA and bone status in JIA patients compared with controls and identified factors associated with musculoskeletal deficits in JIA.The median duration of JIA was 40 months; 29% of the JIA patients had active arthritis, and 28% had received glucocorticoid therapy during the previous year. Compared with the controls, the mCSA and section modulus Z scores were significantly lower in patients with polyarticular JIA and those with SpA. Trabecular vBMD Z scores were significantly lower in patients with polyarticular JIA, those with systemic JIA, and those with SpA. Significant predictors of musculoskeletal deficits included active arthritis in the previous 6 months (mCSA), temporomandibular joint disease (mCSA and section modulus), functional disability (mCSA and vBMD), short stature (vBMD), infliximab exposure (vBMD), and JIA duration (section modulus). The section modulus was significantly reduced relative to mCSA in patients with JIA after adjustment for age and limb length.Marked deficits in vBMD and bone strength occur in JIA in association with severe and longstanding disease. Contrary to the findings of previous studies, bone deficits were greater than expected relative to the mCSA, which illustrates the importance of adjusting for age and bone length.

View details for DOI 10.1002/art.23683

View details for Web of Science ID 000259055400037

View details for PubMedID 18668565
Special report on the 2007 pediatric Position Development Conference of the International Society for Clinical Densitometry SOUTHERN MEDICAL JOURNAL Gordon, C. M., Baim, S., Bianchi, M., Bishop, N. J., Hans, D. B., Kalkwarf, H., Langman, C., Leonard, M. B., Plotkin, H., Rauch, F., Zemel, B. S. 2008; 101 (7): 740-743
Abstract

The International Society for Clinical Densitometry periodically holds Position Development Conferences (PDCs) for the purpose of establishing standards and guidelines for the assessment of skeletal health, including nomenclature, indications, acquisition, analysis, quality control, interpretation, and reporting of bone density tests. Topics are selected for consideration according to criteria that include clinical relevancy, uncertainty in the application of medical evidence to clinical practice, and the likelihood of the expert panel to reach a consensus agreement. The first Pediatric PDC was June 20 to 21, 2007 in Montreal, Quebec, Canada. Topics included fracture prediction and definition of osteoporosis in children; dual-energy x-ray absorptiometry (DXA) assessment in children with chronic disease that may affect the skeleton; DXA interpretation and reporting in children and adolescents; and the use of peripheral quantitative computed tomography in children and adolescents. This report describes the methodology and presents the results of this recent PDC.

View details for Web of Science ID 000257477600018

View details for PubMedID 18580718
Assessment of spine bone mineral density in juvenile idiopathic arthritis: Impact of scan projection JOURNAL OF CLINICAL DENSITOMETRY Dubner, S. E., Shults, J., Leonard, M. B., Zemell, B. S., Sembhi, H., Burnham, J. M. 2008; 11 (2): 302-308
Abstract

Although children with juvenile idiopathic arthritis (JIA) are at risk for vertebral fractures, recent conventional posterior-anterior (PA) spine dual-energy X-ray absorptiometry studies reported minimal areal bone mineral density (aBMD, g/cm2) deficits. Width-adjusted BMD (WA-BMD, g/cm3) represents the bone mineral content (BMC) from the lateral projection, excluding the dense cortical spinous processes, divided by the estimated vertebral body volume based on paired PA-lateral bone dimensions. Therefore, WA-BMD may be more sensitive to JIA effects on the predominantly trabecular vertebral body. Age- and sex-specific Z-scores for spine aBMD and WA-BMD were generated in 84 JIA subjects compared with healthy controls, aged 5-21 yr. JIA was associated with lower mean WA-BMD Z-scores (-0.78, 95% CI: -1.03, -0.53; p<0.001) and aBMD Z-scores (-0.26, 95% CI: -0.49, -0.02; p<0.05), compared with controls. WA-BMD Z-scores were significantly lower than aBMD Z-scores in JIA (p<0.001). A significant JIA by age interaction (p<0.001) indicated that the magnitude of the difference between WA-BMD and aBMD Z-scores was greater in younger subjects. In conclusion, WA-BMD may be more sensitive to disease effects in children because it selectively measures the trabecular-rich vertebral body and is independent of growth-related changes in BMC of the dense spinous processes.

View details for DOI 10.1016/j.jocd.2007.10.005

View details for Web of Science ID 000256640900012

View details for PubMedID 18164636
Observational study of bone accretion during successful weight loss in obese adolescents OBESITY Stettler, N., Berkowtiz, R. I., Cronquist, J. L., Shults, J., Wadden, T. A., Zemel, B. S., Leonard, M. B. 2008; 16 (1): 96-101
Abstract

To assess bone mineral content (BMC) among obese adolescents who lose weight during a critical period for bone accretion.Whole body, lumbar spine, lower, and upper limb BMC were measured in 62 obese adolescents who completed an intensive 12-month weight loss trial. BMC was adjusted for height (z -scores) using data from a reference group of 66 adolescents (who were 18% overweight).At baseline, the BMC of the obese group was higher than the reference group. During the 12-month weight loss program, unadjusted BMC increased among the obese adolescents, despite successful weight loss. After adjustment for height, whole body BMC did not change significantly from baseline to 12 months (mean +/- s.d.: 1.08 +/- 0.67 to 1.06 +/- 0.67, P = 0.7). Region-specific BMC-for-height however decreased for the lower (1.07 +/- 0.57 to 0.95 +/- 0.59, P < 0.001) and upper (1.29 +/- 0.56 to 1.18 +/- 0.57, P = 0.01) limbs, but lumbar spine BMC-for-height increased (0.14 +/- 1.06 to 0.40 +/- 0.94, P < 0.001). These changes were largely and independently explained by changes in lean and fat mass.This study confirms that obese adolescents have high BMC for height and suggests that, unlike adults, their BMC continues to increase during weight loss and remains higher than the BMC of a reference group. After adjustment for growth-related changes, lower and upper limb BMC appears to decrease, while lumbar spine BMC appears to increase. These results suggest that to optimize the health benefits of weight loss among obese adolescents, their bone health should be better understood and addressed.

View details for DOI 10.1038/oby.2007.17

View details for Web of Science ID 000252554300017

View details for PubMedID 18223619
Official positions of the International Society for Clinical Densitometry and executive summary of the 2007 ISCD Pediatric Position Development Conference JOURNAL OF CLINICAL DENSITOMETRY Baim, S., Leonard, M. B., Bianchi, M., Hans, D. B., Kalkwarf, H. J., Langman, C. B., Rauch, F. 2008; 11 (1): 6-21
Abstract

The International Society for Clinical Densitometry (ISCD) convenes a Position Development Conference (PDC) every 2 yr to make recommendations for standards in the field of bone densitometry. The recommendations are based on clinically relevant issues in bone densitometry such as quality control, acquisition, analysis, interpretation, and reporting. In 2007, ISCD convened its first Pediatric Position Development Conference to address issues specific to the assessment of skeletal health in children and adolescents. Topics for consideration are developed by the ISCD Board of Directors and its Scientific Advisory Committee. Clinically relevant questions related to each topic area are assigned to task forces for a comprehensive review of the medical literature and subsequent presentation of the reports to an international panel of experts. For this PDC, the Expert Panel included representatives of the American Society for Bone and Mineral Research and International Bone and Mineral Society. The recommendations of the PDC Expert Panel are then reviewed by the ISCD Board of Directors. Recommendations that are approved become Official Positions of the ISCD. The Pediatric PDC was held June 20-21, 2007, in Montreal, Quebec, Canada. Topics considered were restricted to children and adolescents, and included DXA prediction of fracture and definition of osteoporosis; DXA assessment in diseases that may affect the skeleton; DXA interpretation and reporting; and peripheral quantitative computed tomography measurement. This report describes the methodology and results of the 2007 Pediatric PDC, and a summary of all ISCD Official Positions, including the ones recently adopted by this 2007 Pediatric PDC and the 2007 Lansdowne, Virginia, USA Adult PDC.

View details for DOI 10.1016/j.jocd.2007.12.002

View details for Web of Science ID 000255568300002

View details for PubMedID 18442749
Volumetric bladder ultrasound performed by trained nurses increases catheterization success in pediatric patients Annual Meeting of the Society-of-Academic-Emergency-Medicine Baumann, B. M., McCans, K., Stahmer, S. A., Leonard, M. B., Shults, J., Holmes, W. C. W B SAUNDERS CO-ELSEVIER INC. 2008: 18–23
Abstract

The objective of the study was to determine whether the use of volumetric ultrasound by trained pediatric emergency department (ED) nurses improves first-attempt urine collection success rates.This randomized controlled trial was conducted in children aged < or = 36 months requiring diagnostic urine samples. Children were randomized to either the conventional (nonimaged) or the ultrasound arm. Demographics, number of catheterizations required for success, postponements, and collection times were recorded.Forty-five children were assigned to the conventional and 48 to the ultrasound arm (n = 93). First-attempt success rates were higher in the ultrasound arm: 67% (conventional) vs 92% (ultrasound) (P = .003). Both urinalysis and culture were less likely to be completed on conventional group specimens (91% vs 100%; P = .04). However, mean conventional group urine collection time was less than the ultrasound group's collection time (12 vs 28 minutes; P < .001).Although there is a time delay, urine collection in the ultrasound arm generated a significant improvement over conventional catheterization in obtaining an adequate urine sample.

View details for DOI 10.1016/j.ajem.2007.03.020

View details for Web of Science ID 000252161800004

View details for PubMedID 18082776
Vitamin D insufficiency in children, adolescents, and young adults with cystic fibrosis despite routine oral supplementation AMERICAN JOURNAL OF CLINICAL NUTRITION Rovner, A. J., Stallings, V. A., Schall, J. I., Leonard, M. B., Zemel, B. S. 2007; 86 (6): 1694-1699
Abstract

Cystic fibrosis (CF) with pancreatic insufficiency is associated with poor absorption of fat and fat-soluble vitamins, including vitamin D. Pancreatic enzyme supplementation does not completely correct fat malabsorption in CF patients.The objective of the study was to compare the vitamin D status of children, adolescents, and young adults with CF who were treated with routine vitamin D and pancreatic enzyme supplements with the vitamin D status of a healthy reference group from a similar geographic area.Growth, dietary intake, and serum concentrations of 25-hydroxyvitamin D [25(OH)D], 1,25-dihydroxyvitamin D [1,25(OH)(2)D], and parathyroid hormone (PTH) were measured in 101 white subjects with CF and a reference group of 177 white subjects.The median daily vitamin D supplementation in the CF group was 800 IU. The mean +/- SD serum concentrations of 25(OH)D were 20.7 +/- 6.5 ng/mL in the CF group and 26.2 +/- 8.6 ng/mL in the reference group (P < 0.001). Vitamin D deficiency and insufficiency were defined as 25(OH)D concentrations < 11 ng/mL and < 30 ng/mL, respectively. Seven percent of the CF group and 2% of the healthy reference group were vitamin D deficient (P < 0.03). Ninety percent of the CF group and 74% of the healthy reference group were vitamin D insufficient (P < 0.01). Twenty-five percent of the CF group and 9% of the healthy reference group had elevated PTH (P < 0.006). The odds of vitamin D insufficiency in the CF group, compared with the healthy reference group, were 1.2 (95% CI: 1.1, 1.3) after adjustment for season and age.Despite daily vitamin D supplementation, serum 25(OH)D concentrations remain low in children, adolescents, and young adults with CF.

View details for Web of Science ID 000251575500018

View details for PubMedID 18065588
A structural approach to the assessment of fracture risk in children and adolescents with chronic kidney disease PEDIATRIC NEPHROLOGY Leonard, M. B. 2007; 22 (11): 1815-1824
Abstract

Children with chronic kidney disease (CKD) have multiple risk factors for impaired accretion of trabecular and cortical bone. CKD during childhood poses an immediate fracture risk and compromises adult bone mass, resulting in significantly greater skeletal fragility throughout life. High-turnover disease initially results in thickened trabeculae, with greater bone volume. As disease progresses, resorption cavities dissect trabeculae, connectivity degrades, and bone volume decreases. Increased bone turnover also results in increased cortical porosity and decreased cortical thickness. Dual-energy X-ray absorptiometry (DXA)-based measures of bone mineral density (BMD) are derived from the total bone mass within the projected bone area (g/cm(2)), concealing distinct disease effects in trabecular and cortical bone. In contrast, peripheral quantitative computed tomography (pQCT) estimates volumetric BMD (vBMD, g/cm(3)), distinguishes between cortical and trabecular bone, and provides accurate estimates of cortical dimensions. Recent data have confirmed that pQCT measures of cortical vBMD and thickness provide substantially greater fracture discrimination in adult dialysis patients compared with hip or spine DXA. The following review considers the structural effects of renal osteodystrophy as it relates to fracture risk and the potential advantages and disadvantages of DXA and alternative measures of bone density, geometry, and microarchitecture, such as pQCT, micro-CT (microCT), and micro magnetic resonance imaging (microMRI) for fracture risk assessment.

View details for DOI 10.1007/s00467-007-0490-6

View details for Web of Science ID 000249820000002

View details for PubMedID 17622566
Caregiver and health care provider satisfaction with volumetric bladder ultrasound ACADEMIC EMERGENCY MEDICINE Baumann, B. M., McCans, K., Stahmer, S. A., Leonard, M. B., Shults, J., Holmes, W. C. 2007; 14 (10): 903-907
Abstract

Conventional (nonimaged) bladder catheterization has lower first-attempt success rates (67%-72%) when compared with catheterization aided by volumetric bladder ultrasonography (US) (92%-100%), yet the total time to urine sample collection with US can be quite lengthy. Given the advantage and disadvantages, the authors assessed caregiver and health care provider satisfaction with these two methods.Caregivers and health care providers of children enrolled in a prospective, randomized, controlled trial examining the first-attempt urine collection success rates with these two methods completed standardized questionnaires. Each child's caregiver, nurse, and physician noted their perceptions, satisfaction, and future preferences using Likert-scale assessments.Of 93 caregivers, 45 had children randomized to the conventional arm and 48 to the US arm. Nine physicians and three nurses participated. Both caregiver groups had similar previous catheterization experience; none had children undergo volumetric bladder sonography. Caregivers in the conventional group rated their children's discomfort higher (4.4 vs. 3.4; p = 0.02) and were less satisfied (4.5 vs. 6.4; p < 0.0001) than those in the US group. Nurses' satisfaction with catheterization in the conventional group was lower than in the US group (3.0 vs. 5.5), as was physicians' satisfaction (4.3 vs. 5.7; p < 0.0001). Both nurses and physicians indicated that they would be less likely to use conventional catheterization in future attempts.Caregivers in the conventional group rated their children's discomfort higher than did caregivers in the US group. Both caregivers and health care providers expressed greater satisfaction with US and were more likely to prefer this imaging modality with future catheterization attempts.

View details for DOI 10.1197/j.aem.2007.06.041

View details for Web of Science ID 000250020700012

View details for PubMedID 17898252
Gender differences in body composition deficits at diagnosis in children and adolescents with Crohn's disease INFLAMMATORY BOWEL DISEASES Thoyu, M., Shults, J., Burnham, J. M., Zemel, B. S., Baldassano, R. N., Leonard, M. B. 2007; 13 (9): 1121-1128
Abstract

Childhood Crohn's disease (CD) is associated with poor growth and decreased body mass index (BMI); however, lean mass (LM) and fat mass (FM) deficits prior to therapy have not been characterized.To quantify LM and FM in incident pediatric CD subjects and controls, and to identify determinants of LM and FM deficits.Whole body LM and FM were assessed using DXA in 78 CD subjects and 669 healthy controls, ages 5-21 yr. Gender specific z-scores for LM (LM-Ht) and FM (FM-Ht) relative to height were derived using log linear regression models in the controls. Multivariate linear regression models adjusted for potential confounders.CD was associated with significantly lower height and BMI for age. Within CD subjects, FM-Ht and LM-Ht were significantly lower in females compared with males (FM-Ht z: -0.66+/-0.83 vs. -0.08+/-0.95, p<0.01; LM-Ht z: -1.12+/-1.12 vs. -0.57+/-0.99, p<0.05). In females, CD was associated with significantly lower LM-Ht (p<0.001) and FM-Ht (p=0.001), adjusted for age, race and Tanner stage, compared with controls. LM and FM deficits were significantly greater in older females with CD; 47% of adolescent females had LM-Ht
View details for DOI 10.1002/ibd.20149

View details for Web of Science ID 000249109500009

View details for PubMedID 17427245
Risk factors for low serum 25-hydroxyvitamin D concentrations in otherwise healthy children and adolescents AMERICAN JOURNAL OF CLINICAL NUTRITION Weng, F. L., Shults, J., Leonard, M. B., Stallings, V. A., Zemel, B. S. 2007; 86 (1): 150-158
Abstract

Serum 25-hydroxyvitamin D [25(OH)D] concentrations serve as a biomarker for vitamin D stores. Prior studies have not examined the risk factors for low vitamin D concentrations in a multiethnic sample of US youth across a broad age range.The objective was to determine the prevalence of and factors associated with low concentrations of 25(OH)D in children and adolescents.Serum 25(OH)D concentrations were measured in 382 healthy children aged 6-21 y living in the northeastern United States. Dietary and supplemental vitamin D intake was assessed by interview. Fat and lean mass were assessed by dual-energy X-ray absorptiometry. Multivariable ordinal logistic regression was used to determine factors associated with decreased concentrations of 25(OH)D.The median concentration of 25(OH)D was 28 ng/mL (interquartile range: 19-35 ng/mL), and 55% of subjects had 25(OH)D concentrations <30 ng/mL. 25(OH)D concentrations were inversely correlated with parathyroid hormone concentrations (Spearman's r=-0.31, P<0.001) but were not significantly correlated with 1,25-dihydroxyvitamin D concentrations. In the multivariable model, older age (P<0.001), black race [odds ratio (OR): 14.2; 95% CI: 8.53, 23.5], wintertime study visit (OR: 3.55; 95% CI: 2.29, 5.50), and total daily vitamin D intake <200 IU (OR: 1.58; 95% CI: 1.02, 2.46) were associated with low vitamin D concentrations. Fat and lean mass were not independently associated with vitamin D status in this healthy-weight sample.Low serum 25(OH)D concentrations are prevalent in otherwise healthy children and adolescents in the northeastern United States and are related to low vitamin D intake, race, and season.

View details for Web of Science ID 000247981900022

View details for PubMedID 17616775
Alterations in proximal femur geometry in children treated with glucocorticoids for Crohn disease or nephrotic syndrome: Impact of the underlying disease JOURNAL OF BONE AND MINERAL RESEARCH Burnham, J. M., Shults, J., Petit, M. A., Semeao, E., Beck, T. J., Zemel, B. S., Leonard, M. B. 2007; 22 (4): 551-559
Abstract

Proximal femur geometry was assessed in children and young adults treated with chronic GCs for CD or SSNS. Subperiosteal width and section modulus were significantly lower in CD and greater in SSNS compared with controls, highlighting the importance of the underlying disease, persistent inflammation, and alterations in lean mass.The impact of glucocorticoid (GC) therapy on bone structure during growth is unknown. Our objective was to characterize proximal femur geometry in children and young adults with Crohn disease (CD) or steroid-sensitive nephrotic syndrome (SSNS) compared with controls and to evaluate the influence of lean mass and GC therapy on bone parameters.DXA scans of the hip and whole body were obtained in 88 subjects with CD, 65 subjects with SSNS, and 128 controls (4-26 years of age). Hip structural analysis parameters (subperiosteal width, cross-sectional area [CSA], and section modulus in the narrow neck [NN], intertrochanteric region [IT], and femoral shaft [FS]), areal BMD, and whole body lean mass were expressed as Z scores compared with controls. Multivariable linear regression was used to adjust outcomes for group differences in age, sex, race, and height.Mean lean mass Z scores were lower in CD (-0.63, p < 0.001) and greater in SSNS (0.36, p = 0.03) compared with controls. Hip areal BMD Z scores were lower in CD (-0.73, p < 0.001) but not SSNS (-0.02, p > 0.2) compared with controls. In CD, Z scores for subperiosteal width (NN: -1.66, p < 0.001; FS: -0.86, p < 0.001) and section modulus (NN: -0.60, p = 0.003; FS: -0.36, p = 0.03) were significantly lower than controls. In contrast, in SSNS, Z scores were greater for IT subperiosteal width (0.39, p = 0.02), FS CSA (0.47, p = 0.005), and FS section modulus (0.49, p = 0.004). Alterations in section modulus in CD and SSNS were eliminated after adjustment for lean mass. Cumulative GC dose was inversely associated with FS subperiosteal width and section modulus only in CD.These data show that the effects of GC on proximal femur geometry during growth are influenced by the underlying disease, persistent inflammation, and alterations in lean mass. These data also provide insight into the structural basis of hip fragility in CD.

View details for DOI 10.1359/JBMR.070110

View details for Web of Science ID 000245234000009

View details for PubMedID 17243860
Glucocorticoid-induced osteoporosis in children: Impact of the underlying disease Workshop on Skeletal Effects of Pharmacologic Agents in Children Leonard, M. B. AMER ACAD PEDIATRICS. 2007: S166–S174
Abstract

Glucocorticoids inhibit osteoblasts through multiple mechanisms, which results in significant reductions in bone formation. The growing skeleton may be especially vulnerable to adverse glucocorticoid effects on bone formation, which could possibly compromise trabecular and cortical bone accretion. Although decreased bone mineral density has been described in various pediatric disorders that require glucocorticoids, and a population-based study reported increased fracture risk in children who require >4 courses of glucocorticoids, some of the detrimental bone effects attributed to glucocorticoids may be caused by the underlying inflammatory disease. For example, inflammatory cytokines that are elevated in chronic disease, such as tumor necrosis factor alpha, suppress bone formation and promote bone resorption through mechanisms similar to glucocorticoid-induced osteoporosis. Summarized in this review are changes in bone density and dimensions during growth, the effects of glucocorticoids and cytokines on bone cells, the potential confounding effects of the underlying inflammatory-disease process, and the challenges in interpreting dual-energy x-ray absorptiometry results in children with altered growth and development in the setting of glucocorticoid therapy. Two recent studies of children treated with chronic glucocorticoids highlight the differences in the effect of underlying disease, as well as the importance of associated alterations in growth and development.

View details for DOI 10.1542/peds.2006-2023J

View details for Web of Science ID 000247759900008

View details for PubMedID 17332238
Quantitative microcomputed tomography assessment of intratrabecular, intertrabecular, and cortical bone architecture in a rat model of severe renal osteodystrophy JOURNAL OF COMPUTER ASSISTED TOMOGRAPHY Hopper, T. A., Wehrli, F. W., Saha, P. K., Andre, J. B., Wright, A. C., Sanchez, C. P., Leonard, M. B. 2007; 31 (2): 320-328
Abstract

To determine the effects of renal osteodystrophy (ROD) on bone microarchitecture in growing rats.A total of 24 rats underwent 5/6 nephrectomy (NX) and were fed a high-phosphorus diet to induce ROD; another 6 underwent sham NX. In vitro microcomputed tomography images (GEMS, London, Ontario, Canada) were obtained in the femoral metaphysis and midshaft.Trabecular and cortical bone volume/total volume (BV/TV) were significantly lower in NX specimens because of pores within the trabeculae and along the endosteal surface. Topological analysis using component labeling in 3-dimensions verified that trabecular pores connected to the marrow space. After the trabecular pores were filled using a morphological filter, trabecular thickness was significantly increased in NX. In contrast, cortical thickness was significantly decreased in NX compared with controls; however, after filling the endocortical pores, thickness did not differ.The ROD resulted in decreased cortical and trabecular BV/TV, increased porosity, and increased trabecular thickness. Advanced image processing algorithms demonstrated the effects of cortical and trabecular porosity on BV/TV and structure in ROD.

View details for Web of Science ID 000245456700027

View details for PubMedID 17414773
Improved generalized estimating equation analysis via xtqls for quasi-least squares in Stata STATA JOURNAL Shults, J., Ratcliffe, S. J., Leonard, M. 2007; 7 (2): 147-166
View details for Web of Science ID 000248072200001
The dysfunctional muscle-bone unit in juvenile idiopathic arthritis. Journal of musculoskeletal & neuronal interactions Burnham, J. M., Shults, J., Sembhi, H., Zemel, B. S., Leonard, M. B. 2006; 6 (4): 351-352
View details for PubMedID 17185819
Childhood onset arthritis is associated with an increased risk of fracture: a population based study using the General Practice Research Database ANNALS OF THE RHEUMATIC DISEASES Burnham, J. M., Shults, J., Weinstein, R., Lewis, J. D., Leonard, M. B. 2006; 65 (8): 1074-1079
Abstract

Childhood onset arthritis is associated with low bone mass and strength.To determine whether childhood onset arthritis is associated with greater fracture risk.In a retrospective cohort study all subjects with onset of arthritis between 1 and 19 years of age in the United Kingdom General Practice Research Database were identified. As controls, all sex and age matched subjects from a practice that included a subject with arthritis were included. Incidence rate ratios (IRRs) for first fracture were generated using Mantel-Haenszel methods and Poisson regression.1939 subjects with arthritis (51% female) and 207 072 controls (53% female) were identified. The median age at arthritis diagnosis was 10.9 years. A total of 129 (6.7%) first fractures were noted in subjects with arthritis compared with 6910 (3.3%) in controls over a median follow up of 3.90 and 3.95 years in the subjects with arthritis and controls, respectively. The IRR (95% confidence interval) for first fracture among subjects with arthritis, compared with controls, according to the age at the start of follow up were 1.49 (0.91 to 2.31) for age <10 years, 3.13 (2.21 to 4.33) at 10-15 years, 1.75 (1.18 to 2.51) at 15-20 years, 1.40 (0.91 to 2.08) at 20-45 years, and 3.97 (2.23 to 6.59) at >45 years.Childhood onset arthritis is associated with a clinically significant increased risk of fracture in children, adolescents and, possibly, adults. Studies are urgently needed to characterise the determinants of structural bone abnormalities in childhood arthritis and devise prevention and treatment strategies.

View details for DOI 10.1136/ard.2005.048835

View details for Web of Science ID 000239006000016

View details for PubMedID 16627541
Risk factors for glucocorticoid-induced obesity in children with steroid-sensitive nephrotic syndrome PEDIATRIC NEPHROLOGY Foster, B. J., Shults, J., Zemel, B. S., Leonard, M. B. 2006; 21 (7): 973-980
Abstract

The objective of this work was to determine the prevalence of obesity, defined as BMI >95th percentile, in children treated with glucocorticoids for steroid-sensitive nephrotic syndrome (SSNS), and to identify risk factors for the development for glucocorticoid-induced obesity. The experimental design involved a cross-sectional study of 96 individuals (4 to 21 yrs) treated with glucocorticoids for SSNS and 186 healthy reference subjects. Logistic regression was used to generate odds ratios for obesity. Glucocorticoid exposure was classified as recent in the 54 subjects treated with glucocorticoids in the prior six months, and remote in the remaining 42 subjects. Recent exposure was associated with significantly increased odds of obesity [odds ratio (95% CI): 26.14 (7.54, 90.66)] in non-blacks only. Each one-unit increase in maternal BMI was associated with a 35% increase in the odds of obesity in recent SSNS subjects (p=0.003). The effect of maternal BMI on the odds of obesity was significantly greater in recent SSNS subjects than in reference subjects (test for interaction p=0.038). The odds of obesity were also significantly increased [odds ratio 5.22 (1.77, 15.41), p=0.003] in all subjects with remote glucocorticoid exposure (black and non-black). These results indicate that non-black race and increased maternal BMI are risk factors for glucocorticoid-induced obesity in subjects with recent exposure.

View details for DOI 10.1007/s00467-006-0100-z

View details for Web of Science ID 000238293200014

View details for PubMedID 16773410
DXA estimates of vertebral volumetric bone mineral density in children: Potential advantages of paired posteroanterior and lateral scans JOURNAL OF CLINICAL DENSITOMETRY Leonard, M. B., Shults, J., Zemel, B. S. 2006; 9 (3): 265-273
Abstract

Dual-energy X-ray absorptiometry (DXA) estimates of areal bone mineral density (BMD) are confounded by bone size in children. Two strategies have been proposed to estimate vertebral volumetric BMD: (1) bone mineral apparent density (BMAD) is based on the posteroanterior (PA) spine scan; (2) width-adjusted bone mineral density (WABMD) is based on paired PA lateral scans. The objective of this study was to compare DXA estimates of vertebral bone mineral content (BMC), volume and volumetric BMD obtained from Hologic PA scans (Hologic, Inc., Bedford, MA) alone, and paired PA lateral scans in 124 healthy children, ages 4 to 20 yr. The PA scans were used to estimate bone volume (PA Volume) as (PA Area)1.5 and BMAD as [(PA BMC)/(PA Volume)]. Paired PA lateral scans were used to estimate width-adjusted bone volume (WA Volume) as [(pi/4)(PA width)(lateral depth)(vertebral height)] and WABMD as [(lateral BMC)/(WA Volume)]. Generalized estimating equations were used to compare the relationship between scan type (PA vs. paired PA lateral) and bone outcomes, and the effects of height and maturation on this relationship. The estimates of BMC and volume derived from PA scans and paired PA lateral scans were highly correlated (r>0.97); WABMD and BMAD were less correlated (r=0.81). The increases in BMC, volume, and volumetric BMD with greater height and maturation were significantly larger (all p<0.001) when estimated from paired PA lateral scans, compared with PA scans alone. The proportion of spine BMC contained within the vertebral body, versus the cortical spinous processes, increased significantly with age (p<0.001) from 28% to 69%. The smaller increases in bone measures on PA scans may have been due to magnification error by the fan beam as posterior tissue thickness increased in taller, more mature subjects, and the distance of the vertebrae from the X-ray source increased. In conclusion, paired Hologic PA lateral scans may increase sensitivity to growth-related increases in trabecular BMC and density in the spine, with less bias due to magnification error.

View details for DOI 10.1016/j.jocd.2006.05.008

View details for Web of Science ID 000240321200003

View details for PubMedID 16931343
Predictors of immunomodulator use as early therapy in pediatric Crohn's disease JOURNAL OF CLINICAL GASTROENTEROLOGY Jacobstein, D. A., Mamula, P., Markowitz, J. E., Leonard, M., Baldassano, R. N. 2006; 40 (2): 145-148
Abstract

The goals of this study were to identify markers in a patient's presentation and disease progression that predict the need for the use of immunomodulators in a pediatric population.Although immunomodulator safety and efficacy have been documented in Crohn's disease, models for predicting outcome and the need for immunomodulators (azathioprine, 6-mercaptopurine, or methotrexate) early in the disease course have not been investigated in children or adults.Data on newly diagnosed Crohn's disease patients were prospectively collected within 3 weeks of diagnosis, 6 months after diagnosis, and 1 year after diagnosis. Information collected at each visit included medication use and disease activity assessment.A total of 57 patients who were followed for > or = 6 months were evaluated. Overall, 34 of 57 (59.6%) were started on immunomodulators within 1 year of diagnosis. Mean serum albumin (3.35 g/dL vs. 3.7 g/dL, P = 0.013) and hematocrit (33.3% vs. 35.9%, P = 0.023) at diagnosis were lower, and erythrocyte sedimentation rate (32 vs. 12, P = 0.011) at diagnosis was higher in patients who required immunomodulators. The total Pediatric Crohn's Disease Activity Index score as well as the physical examination score and patient recall score within the PCDAI at diagnosis were not different among those who received immunomodulators and those that did not.Immunomodulators are frequently used within 1 year of diagnosis in pediatric Crohn's disease. Lower serum albumin levels and hematocrit, and elevated erythrocyte sedimentation rate at diagnosis may predict the need for immunomodulators earlier in the disease course.

View details for Web of Science ID 000234966200011

View details for PubMedID 16394876
The state of pediatric bone: Summary of the ASBMR pediatric bone initiative JOURNAL OF BONE AND MINERAL RESEARCH Klein, G. L., Fitzpatrick, L. A., Langman, C. B., Beck, T. J., Carpenter, T. O., Gilsanz, V., Holm, I. A., Leonard, M. B., Specker, B. L. 2005; 20 (12): 2075-2081
View details for DOI 10.1359/JBMR.050901

View details for Web of Science ID 000233517700001

View details for PubMedID 16294260
Bone area and bone mineral content deficits in children with sickle cell disease PEDIATRICS Buison, A. M., Kawchak, D. A., Schall, J. I., Ohene-Frempong, K., Stallings, V. A., Leonard, M. B., Zemel, B. S. 2005; 116 (4): 943-949
Abstract

Children with sickle cell disease (SCD) experience poor growth, altered body composition, and delayed maturation. Deficits in bone mineral content (BMC) and bone area (BA) have not been well characterized. The objectives of this study were to assess whole-body BMC (WBBMC) and WBBA in children with SCD, type SS (SCD-SS), compared with healthy control subjects, adjusted for growth and body composition, and to determine the relationships of WBBMC and WBBA to bone age and hematologic parameters in children with SCD-SS.WBBMC, WBBA, and lean mass were measured by dual-energy x-ray absorptiometry in children who were aged 4 to 19 years. Growth, sexual development, and bone age were assessed. Gender-specific z scores for WBBMC relative to age and height were generated from control data.Ninety children with SCD-SS and 198 healthy control subjects were evaluated. SCD-SS was associated with poor growth. WBBMC was significantly decreased in SCD-SS compared with control subjects, adjusted for age, height, pubertal status, and lean mass. WBBMC relative to age and WBBMC relative to height z scores were -0.95 +/- 0.99 and -0.54 +/- 0.97, respectively, and were associated with hemoglobin and hematocrit levels and history of delayed bone age.Children with SCD-SS have significant deficits in WBBMC that persist despite adjustment for poor growth and decreased lean mass. These children may be at increased risk for fragility fractures and suboptimal peak bone mass.

View details for DOI 10.1542/peds.2005-2582

View details for Web of Science ID 000232289700019

View details for PubMedID 16199706
Mild to moderate cystic fibrosis is not associated with increased fracture risk in children and adolescents JOURNAL OF PEDIATRICS Rovner, A. J., Zemel, B. S., Leonard, M. B., Schall, J. I., Stallings, V. A. 2005; 147 (3): 327-331
Abstract

To determine whether children and adolescents with cystic fibrosis (CF), pancreatic insufficiency (PI), and mild-to-moderate lung disease have an increased risk of fracture compared with concurrent healthy control subjects.A lifetime fracture history questionnaire was administered to 186 subjects (ages 6 to 25 years) with CF, PI and mild-to-moderate lung disease and 427 healthy white control subjects (ages 4 to 25 years).A fracture was reported by 24% of subjects with CF and 23% of healthy control subjects. Average age of first fracture was similar between the groups (8.3 years for subjects and 8.8 years for controls). The radius/ulna was the most common fracture site in both groups. Risk of fracture, adjusted for sex and age, was not greater in the CF group compared with the control group (hazard ratio: 0.96, 95% CI: 0.68, 1.30, P = .82).Children and adolescents with CF, PI, and mild-to-moderate lung disease were not at an increased risk of fracture.

View details for DOI 10.1016/j.jpeds.2005.04.015

View details for Web of Science ID 000232412100014

View details for PubMedID 16182670
Body-corn position alterations consistent with cachexia in children and young adults with Crohn disease AMERICAN JOURNAL OF CLINICAL NUTRITION Burnham, J. M., Shults, J., Semeao, E., Foster, B. J., Zemel, B. S., Stallings, V. A., Leonard, M. B. 2005; 82 (2): 413-420
Abstract

Crohn disease (CD) in children is associated with low body mass index (BMI), poor growth, and delayed maturation; alterations in lean and fat mass, however, are poorly characterized.The objective was to quantify lean and fat mass in children and young adults with CD and in healthy control subjects, relative to height and pubertal maturation.This cross-sectional study assessed whole-body lean and fat mass by using dual-energy X-ray absorptiometry in 104 subjects with CD and in 233 healthy control subjects aged 4-25 y. Linear regression was used to determine the effect of CD on body composition and to generate sex-specific SD scores (z scores) for lean and fat mass relative to height.Subjects with CD had lower height-for-age and BMI-for-age z scores (P < 0.001 for both) than did control subjects. CD was associated with significant deficits in lean mass after adjustment for height, age, race, and Tanner stage (P = 0.003); deficits in fat mass were not observed. The mean (+/-SD) lean mass-for-height and fat mass-for-height z scores in the subjects with CD were -0.61 +/- 0.92 and -0.04 +/- 0.86, respectively. Within the control group, fat mass-for-height was positively correlated with lean mass-for height (r = 0.41, P < 0.0001); this association was absent in the subjects with CD.Children and young adults with CD had significant deficits in lean mass but preserved fat mass, which is consistent with cachexia. Further research is needed to identify physical activity, nutritional, and antiinflammatory interventions to improve body composition in persons with CD.

View details for Web of Science ID 000231293100021

View details for PubMedID 16087987
First NIH/office of rare diseases conference on cystinosis: Past, present, and future PEDIATRIC NEPHROLOGY Kleta, R., Kaskel, F., Dohil, R., Goodyer, P., Guay-Woodford, L. M., Harms, E., Ingelfinger, J. R., Koch, V. H., Langman, C. B., Leonard, M. B., Mannon, R. B., Sarwal, M., Schneider, J. A., Skovby, F., Sonies, B. C., Thoene, J. G., Trauner, D. A., Gahl, W. A. 2005; 20 (4): 452-454
View details for DOI 10.1007/s00467-004-1777-5

View details for Web of Science ID 000227442100003

View details for PubMedID 15747161
Proximal femur bone geometry is appropriately adapted to lean mass in overweight children and adolescents BONE Petit, M. A., Beck, T. J., Shults, J., Zemel, B. S., Foster, B. J., Leonard, M. B. 2005; 36 (3): 568-576
Abstract

It is unclear if the bones of overweight children are appropriately adapted to increased loads. The objective of this study was to compare bone geometry in 40 overweight (body mass index [BMI] > 85th percentile) and 94 healthy weight (BMI < or = 85th percentile) subjects, ages 4-20 years. Dual energy X-ray absorptiometry (Hologic QDR 2000) scans were analyzed at the femoral shaft (FS) and narrow neck (NN) by the Hip Structure Analysis program. Subperiosteal width, cortical thickness and indices of bone axial and bending strength (bone cross-sectional area [CSA] and section modulus [Z]) were measured from bone mass profiles. Multivariate regression models were used to compare overweight and healthy weight subjects. Z was 11 (95% CI 5, 19) and 13 (7, 20) percent higher at the FS and NN, respectively, in overweight subjects (P < 0.001), adjusted for height, maturation and gender. At the NN, higher Z was due to greater subperiosteal width [4% (2, 7)] and bone CSA [10% (5, 16]) and at the FS, to higher bone CSA [10% (5, 16)] and thicker cortices [9% (3, 15)]. When lean mass was added to the models, bone variables did not differ between overweight and healthy weight subjects (P > 0.22), with the exception of NN subperiosteal width [3% (0, 6), P = 0.04]. Fat mass did not contribute significantly to any model. In summary, proximal femur bone geometric strength in overweight children was appropriately adapted to lean mass and height but greater weight in the form of fat mass did not have an independent effect on bone bending strength. These geometric adaptations are consistent with the mechanostat hypothesis that bone strength adapts primarily to muscle forces, not to static loads represented by body weight.

View details for DOI 10.1016/j.bone.2004.12.003

View details for Web of Science ID 000228196900022

View details for PubMedID 15777684
Assessment of bone mass following renal transplantation in children 7th Symposium on Growth and Development in Children with Chronic Kidney Disease Leonard, M. B. SPRINGER. 2005: 360–67
Abstract

Throughout childhood and adolescence, skeletal growth results in site-specific increases in trabecular and cortical dimensions and density. Childhood osteoporosis can be defined as a skeletal disorder characterized by compromised bone strength predisposing to an increased risk of fracture. Pediatric renal transplant recipients have multiple risk factors for impaired bone density and bone strength, including pre-existing renal osteodystrophy, delayed growth and development, malnutrition, decreased weight-bearing activity, inflammation, and immunosuppressive therapies. Dual energy X-ray absorptiometry (DXA) is the most-common method for the assessment of skeletal status in children and adults. However, DXA has many important limitations that are unique to the assessment of bone health in children. Furthermore, DXA is limited in its ability to distinguish between the distinct, and sometimes opposing, effects of renal disease on cortical and trabecular bone. This review summarizes these limitations and the difficulties in assessing and interpreting bone measures in pediatric transplantation are highlighted in a review of select studies. Alternative strategies are presented for clinical and research applications.

View details for DOI 10.1007/s00467-004-1747-y

View details for Web of Science ID 000227713600020

View details for PubMedID 15692834
Impact of simultaneous kidney-pancreas transplant and timing of transplant on kidney allograft survival AMERICAN JOURNAL OF TRANSPLANTATION Israni, A. K., Feldman, H. I., PROPERT, K. J., Leonard, M., Mange, K. C. 2005; 5 (2): 374-382
Abstract

Since 1988 over 10 000 simultaneous cadaveric pancreas-kidney transplants (SPK) have been performed in the United States among patients with end-stage renal disease due to Type 1 diabetes (T1DM). The two aims of this study were to assess the impact on kidney allograft survival of (i) SPK versus transplantation of a kidney alone (KA), and (ii) SPK prior to versus after initiation of chronic dialysis. This retrospective, non-concurrent cohort study examined registry data collected from 8323 patients waitlisted in the United States for an SPK and transplanted with either an SPK or a KA during January 1, 1990 - October 31, 2002. SPK recipients had an adjusted hazard ratio for kidney allograft loss of 0.63 (95% CI: 0.51-0.77, p < 0.001) compared to transplantation without pancreas allograft. SPK recipients who received their allografts prior to beginning chronic dialysis had a lower rate of kidney allograft loss than SPK recipients who received their transplant after initiation of chronic dialysis (adjusted hazard rates (HR) = 0.83, 95% CI: 0.69-0.99, p = 0.042). Simultaneous transplantation of pancreas-kidney compared to kidney transplantation alone and SPK prior to the initiation of chronic dialysis compared to SPK after initiation of dialysis were both associated with longer kidney allograft survival.

View details for DOI 10.1111/j.1600-6143.2004.00688.x

View details for Web of Science ID 000226332700023

View details for PubMedID 15643998
Nutrition in children with kidney disease: Pitfalls of popular assessment methods 1st Joint Congress of the International-Society-for-Peritoneal-Dialysis/European Peritoneal Dialysis Meeting Foster, B. J., Leonard, M. B. MULTIMED INC. 2005: S143–S146
Abstract

Children with chronic kidney disease (CKD) are considered at high risk for protein-energy malnutrition. Clinical practice guidelines generally recommend an evaluation of numerous nutritional parameters to give a complete and accurate picture of nutritional status. This review summarizes the potential limitations of commonly used methods of nutritional assessmentin the setting of CKD. Unrecognized fluid overload and inappropriate normalization of body composition measures are the most important factors leading to misinterpretation of the nutritional assessment in CKD. The importance of expressing body composition measures relative to height or height-age in a population in whom short stature and pubertal delay are highly prevalent is emphasized. The limitations of growth as a marker for nutritional status are also addressed. In addition, the prevailing belief that children with CKD are at high risk for malnutrition is challenged.

View details for Web of Science ID 000230035800038

View details for PubMedID 16048282
Vitamin D insufficiency in steroid-sensitive nephrotic syndrome in remission PEDIATRIC NEPHROLOGY Weng, F. L., Shults, J., Herskovitz, R. M., Zemel, B. S., Leonard, M. B. 2005; 20 (1): 56-63
Abstract

Serum 25-hydroxyvitamin D [25(OH)D] concentrations are the best indicator of vitamin D nutritional status. We measured serum 25(OH)D concentrations in 94 healthy controls and in 41 subjects (aged 4-22 years) with steroid-sensitive nephrotic syndrome (SSNS) in remission. Children with remitted SSNS had significantly lower 25(OH)D concentrations than healthy controls (median 16.4 ng/ml versus 23.9 ng/ml, P<0.001). In a multivariable logistic regression model, the odds ratios (OR) of vitamin D insufficiency [25(OH)D <20 ng/ml] were independently increased in SSNS subjects [OR 11.2 (95% confidence interval 3.5-36.2)], non-whites [OR 12.9 (4.6-36.2)], older children [OR 1.20 per year (1.06-1.36)], and winter months [OR 6.7 (2.5-18.4)]. Within the SSNS subjects, multiple linear regression determined that serum 25(OH)D concentrations were not associated with SSNS disease characteristics measured in this study, such as duration of disease, number of relapses, cumulative glucocorticoids, and interval since last relapse. In conclusion, children with remitted SSNS have lower serum 25(OH)D concentrations than healthy controls. This difference persisted after adjusting for the potential confounding effects of age, race, season, and milk intake. Children with remitted SSNS may benefit from routine measurement of 25(OH)D, but the clinical significance of low 25(OH)D in this population remains unclear.

View details for DOI 10.1007/s00467-004-1694-7

View details for Web of Science ID 000225758100011

View details for PubMedID 15602667
Deficits in size-adjusted bone mass in children with Alagille syndrome JOURNAL OF PEDIATRIC GASTROENTEROLOGY AND NUTRITION Olsen, I. E., Ittenbach, R. F., Rovner, A. J., Leonard, M. B., Mulberg, A. E., Stallings, V. A., Piccoli, D. A., Zemel, B. S. 2005; 40 (1): 76-82
Abstract

To describe bone status in children with Alagille syndrome (AGS) and healthy control children adjusted for age, gender and height (HT), and to identify dietary intake and AGS-related factors associated with bone status.Prepubertal children with AGS and healthy controls comparable in age and ethnicity were evaluated. Subjects were > or =4 years of age, prepubertal and had whole body (WB) and/or lumbar spine (LS) dual energy X-ray absorptiometry (DXA) scans of acceptable quality. Anthropometric (weight, HT), diet and AGS-specific data (e.g., coefficient of fat absorption, labs, liver transplantation) were also collected. Bone area (BA), bone mineral content (BMC) and HT were log transformed for best fit. Bone data were analyzed unadjusted, adjusted for gender, age and HT, and as HT-specific z-scores.AGS and control groups were similar in age, pubertal status and ethnicity. Children with AGS were small-for-age, had decreased BA and BMC-for-age, and decreased WB BA and BMC-for-HT z-scores compared to healthy controls. Prevalence of low BMC-for-HT z-scores (< -2) among AGS subjects was 20% for the WB and 39% for the LS. Bone mineralization was positively related to fat absorption but not dietary intake.Children with AGS have deficits in bone size and bone mass relative to body size. Modifiable factors, such as treatment of malabsorption should be explored as an early focus of AGS care to prevent bone fragility.

View details for Web of Science ID 000226148300014

View details for PubMedID 15625431
Whole body BMC in pediatric Crohn disease: Independent effects of altered growth, maturation, and body composition JOURNAL OF BONE AND MINERAL RESEARCH Burnham, J. M., Shults, J., Semeao, E., Foster, B., Zemel, B. S., Stallings, V. A., Leonard, M. B. 2004; 19 (12): 1961-1968
Abstract

Whole body BMC was assessed in 104 children and young adults with CD and 233 healthy controls. CD was associated with significant deficits in BMC and lean mass, relative to height. Adjustment for lean mass eliminated the bone deficit in CD. Steroid exposure was associated with short stature but not bone deficits relative to height.Children with Crohn disease (CD) have multiple risk factors for impaired bone accrual. The confounding effects of poor growth and delayed maturation limit the interpretation of prior studies of bone health in CD. The objective of this study was to assess BMC relative to growth, body composition, and maturation in CD compared with controls.Whole body BMC and lean mass were assessed by DXA in 104 CD subjects and 233 healthy controls, 4-26 years of age. Multivariable linear regression models were developed to sequentially adjust for differences in skeletal size, pubertal maturation, and muscle mass. BMC-for-height z scores were derived to determine CD-specific covariates associated with bone deficits.Subjects with CD had significantly lower height z score, body mass index z score, and lean mass relative to height compared with controls (all p < 0.0001). After adjustment for group differences in age, height, and race, the ratio of BMC in CD relative to controls was significantly reduced in males (0.86; 95% CI, 0.83, 0.94) and females (0.91; 95% CI, 0.85, 0.98) with CD. Adjustment for pubertal maturation did not alter the estimate; however, addition of lean mass to the model eliminated the bone deficit. Steroid exposure was associated with short stature but not bone deficits.This study shows the importance of considering differences in body size and composition when interpreting DXA data in children with chronic inflammatory conditions and shows an association between deficits in muscle mass and bone in pediatric CD.

View details for DOI 10.1359/JBMR.040908

View details for Web of Science ID 000225341700005

View details for PubMedID 15537438
Racial and center differences in hemodialysis adequacy in children treated at pediatric centers: A North American pediatric renal transplant cooperative study (NAPRTCS) report 36th Annual Meeting of the American-Society-of-Nephrology Leonard, M. B., Stablein, D. M., Ho, M., Jabs, K., Feldman, H. I. AMER SOC NEPHROLOGY. 2004: 2923–32
Abstract

This study assessed hemodialysis adequacy in pediatric centers. Monthly adequacy data were requested in NAPRTCS enrollees on hemodialysis for at least 6 mo. Data forms were returned for 147 children from 32 centers. Data are presented for the 138 children (57% boys, 45% black) that were dialyzed 3 times/wk, representing 2282 patient-months of follow-up. Pre- and postdialysis BUN levels were reported in all children. Kt/V values were reported in 76 children; however, sufficient data were obtained to calculate Kt/V in 129 children. On average, 14.9 Kt/V and 15.2 urea reduction ratio (URR) values were calculated per child. Aggregate dialysis dose was defined as adequate if Kt/V was >1.2 in at least 75% of calculated Kt/V measures within a subject. Mean +/- SD age was 11.3 +/- 3.7 yr (median, 12.0 yr). Hemodialysis dose was variable within subjects (median CV%: URR 8.2, Kt/V 16.9). Aggregate dialysis dose was adequate in 70% of subjects. Multivariate logistic regression showed male gender (OR, 0.41; 95% CI, 0.16 to 0.98), black race (OR, 0.28; 95% CI, 0.11 to 0.67), larger body surface area (fourth versus first quartile: OR, 0.22; 95% CI, 0.05 to 0.80), and absence of reported Kt/V at the treating center (OR, 0.26; 95% CI, 0.10 to 0.62) were significant predictors of inadequate dialysis dose. Age, renal diagnosis, and center size were not associated with adequacy. Racial and gender disparities in hemodialysis dose existed among children at specialized academic pediatric centers and a substantial proportion received inadequate hemodialysis.

View details for DOI 10.1097/01.ASN.0000143475.39388.DE

View details for Web of Science ID 000224684200018

View details for PubMedID 15504946
Interactions between growth and body composition in children treated with high-dose chronic glucocorticoids(1-3) AMERICAN JOURNAL OF CLINICAL NUTRITION Foster, B. J., Shults, J., Zemel, B. S., Leonard, M. B. 2004; 80 (5): 1334-1341
Abstract

Glucocorticoid therapy retards growth during childhood and is believed to lead to a Cushingoid body habitus. However, despite prolonged, repeated courses of glucocorticoid, children with steroid-sensitive nephrotic syndrome (SSNS) have almost normal adult height. Little information exists on body composition.We sought to assess the effect of glucocorticoids on height and body composition by comparing children with SSNS with concurrent healthy reference children. We hypothesized that chronic glucocorticoid therapy leads to obesity, decreased lean mass, and distorted distributions of fat and lean.We performed a cross-sectional study of 52 subjects with SSNS (4-21 y) and 259 reference subjects. The evaluation included height, weight, and pubertal status. Fat and lean masses were assessed by dual-energy X-ray absorptiometry in all subjects. Lifetime glucocorticoid exposure was recorded for subjects with SSNS. Outcomes were expressed as SD scores (SDS).Forty-one percent of subjects with SSNS were obese [body mass index (BMI) > 95th percentile], but regional fat distribution was normal. Mean total lean mass-for-height was 0.43 SD (95% CI: 0.15, 0.72) higher and mean appendicular lean mass-for-total-lean-mass was lower (-0.39 SD; 95% CI: -0.64, -0.14) in SSNS compared with reference children. The mean height-SDS in SSNS was -0.08 SD (95% CI: -0.37, 0.21) relative to national reference data, but height-SDS was significantly decreased given the degree of obesity. Height-SDS was positively associated with BMI-SDS among subjects with SSNS.Glucocorticoid therapy for SSNS is complicated by obesity and relatively low appendicular lean mass. Overall height-SDS is normal because of a mitigating effect of elevated BMI on glucocorticoid-induced growth retardation.

View details for Web of Science ID 000225036000032

View details for PubMedID 15531684
Measuring nutritional status in children with chronic kidney disease AMERICAN JOURNAL OF CLINICAL NUTRITION Foster, B. J., Leonard, M. B. 2004; 80 (4): 801-814
Abstract

Children with chronic kidney disease (CKD) are at risk of protein-energy malnutrition. Existing clinical practice guidelines recognize this and recommend specific methods to assess nutritional status in patients with CKD. This review summarizes the methods for nutritional assessment currently recommended in the United States for children with CKD and details the strengths and limitations of these techniques in the clinical setting. Dietary assessment, serum albumin, height, estimated dry weight, weight/height index, upper arm anthropometry, head circumference, and the protein equivalent of nitrogen appearance are reviewed. We also describe methods for body-composition assessment, such as dual-energy X-ray absorptiometry, bioelectrical impedance analysis (BIA), total body potassium, densitometry, and in vivo neutron activation analysis, pointing out some advantages and disadvantages of each. In CKD, fluid overload is the most important factor leading to misinterpretation of nutritional assessment measures. Abnormalities in the distribution of fat and lean tissue may also compromise the interpretation of some anthropometric measures. In addition, metabolic abnormalities may influence the results obtained by some techniques. Issues specific to evaluating nutritional status in the pediatric population are also discussed, including normalization of nutritional measures to body size and sexual maturity. We stress the importance of expressing body-composition measures relative to height in a population in whom short stature is highly prevalent.

View details for Web of Science ID 000224073000003

View details for PubMedID 15447884
Long-term, high-dose glucocorticoids and bone mineral content in childhood glucocorticoid-sensitive nephrotic syndrome NEW ENGLAND JOURNAL OF MEDICINE Leonard, M. B., Feldman, H. I., Shults, J., Zemel, B. S., Foster, B. J., Stallings, V. A. 2004; 351 (9): 868-875
Abstract

Glucocorticoids suppress bone formation, impair growth, and induce obesity. We determined the effects of long-term treatment with glucocorticoids on bone mineral content in children with glucocorticoid-sensitive nephrotic syndrome, a disorder with minimal known independent effects on bone.We performed dual-energy x-ray absorptiometry of the whole body and spine in 60 children and adolescents with the nephrotic syndrome and 195 control subjects. We used linear regression analysis of log-transformed values to compare the bone mineral content in patients with that in controls.Patients had received an average of 23,000 mg of glucocorticoids and were shorter (P=0.008) and had a greater body-mass index (P<0.001) than controls. The bone mineral content of the spine, adjusted for bone area, age, sex, degree of maturation (Tanner stage), and race, did not differ significantly between patients and controls (ratio, 0.99; 95 percent confidence interval, 0.96 to 1.02; P=0.51). After adjustment for the z score for body-mass index, the bone mineral content of the spine was significantly lower in patients than in controls (0.96; 95 percent confidence interval, 0.92 to 0.99; P=0.01). Whole-body bone mineral content, adjusted for height, age, sex, degree of maturation, and race, was significantly higher in patients than in controls (ratio, 1.11; 95 percent confidence interval, 1.05 to 1.18; P<0.001); however, the addition of the z score for body-mass index to the model eliminated the association with the nephrotic syndrome (ratio, 0.99; 95 percent confidence interval, 0.94 to 1.03; P=0.55).Intermittent treatment with high-dose glucocorticoids during growth does not appear to be associated with deficits in the bone mineral content of the spine or whole body relative to age, bone size, sex, and degree of maturation. Glucocorticoid-induced increases in body-mass index were associated with increased whole-body bone mineral content and maintenance of the bone mineral content of the spine.

View details for Web of Science ID 000223512500008

View details for PubMedID 15329424
Obesity during childhood and adolescence augments bone mass and bone dimensions AMERICAN JOURNAL OF CLINICAL NUTRITION Leonard, M. B., Shults, J., Wilson, B. A., Tershakovec, A. M., Zemel, B. S. 2004; 80 (2): 514-523
Abstract

Studies of the effect of childhood obesity on bone accrual during growth have yielded conflicting results, largely related to the failure to adequately characterize the confounding effects of growth, maturation, and body composition.The objective of this study was to determine the effect of childhood obesity on skeletal mass and dimensions relative to height, body composition, and maturation in males and females.In 132 nonobese (body mass index < 85th percentile) and 103 obese (body mass index > or = 95th percentile) subjects aged 4-20 y, whole-body and vertebral bone mineral content (BMC) was determined by using dual-energy X-ray absorptiometry, and bone area, areal bone mineral density (BMD), and fat and lean masses were measured. Vertebral volumetric BMD was estimated as BMC/area(1.5).Obesity was associated with greater height-for-age, advanced maturation for age, and greater lean mass for height (all P < 0.001). Sex-specific multivariate regressions with adjustment for maturation showed that obesity was associated with greater vertebral areal BMD for height, greater volumetric BMD, and greater vertebral BMC for bone area (all P < 0.05). After adjustment for maturation and lean mass, obesity was associated with significantly greater whole-body bone area and BMC for age and for height (all P < 0.001).In contrast with the results of prior studies, obesity during childhood and adolescence was associated with increased vertebral bone density and increased whole-body bone dimensions and mass. These differences persisted after adjustment for obesity-related increases in height, maturation, and lean mass. Future studies are needed to determine the effect of these differences on fracture risk.

View details for Web of Science ID 000222912800039

View details for PubMedID 15277178
Quantitative high-resolution magnetic resonance imaging reveals structural implications of renal osteodystrophy on trabecular and cortical bone JOURNAL OF MAGNETIC RESONANCE IMAGING Wehrli, F. W., Leonard, M. B., Saha, P. K., Gomberg, B. R. 2004; 20 (1): 83-89
Abstract

To explore the potential role of micro-magnetic resonance imaging (micro-MRI) for quantifying trabecular and cortical bone structural parameters in renal osteodystrophy (ROD), a multifactorial disorder of bone metabolism, traditionally evaluated by bone biopsy.Seventeen hemodialysis patients (average PTH level = 502 +/- 415 microg/liter) were compared with 17 age-, gender-, and body mass index (BMI)-matched control subjects. The average dialysis duration for the patients was 5.5 years (range = 0.96-18.2 years). Three-dimensional (3D) fast large-angle spin-echo (FLASE) MR images of the distal tibia (voxel size = 137 x 137 x 410 microm(3)) were processed to yield bone volume fraction (BV/TV). From a skeletonized representation of the trabecular bone network, the topology of each bone voxel was determined providing surface and curve voxel densities (SURF and CURV) and the topological erosion index (EI). Further, high-resolution two-dimensional (2D) spin-echo images were collected at the tibial midshaft for measurement of cortical bone cross-sectional area (CCA), relative CCA expressed as a percentage of total bone area (RCA), and mean cortical thickness (MCT).The data show both RCA and MCT to be lower in the patients (61.2 vs. 69.1%, P = 0.008, and 4.53 vs. 5.19 mm, P = 0.01). BV/TV and SURF were lower, while EI was increased in the patients, although these differences were not quite significant (P = 0.06-0.09). All of the cortical and trabecular findings are consistent with increased bone fragility.The data suggest that micro-MRI may have potential to characterize the structural implications of metabolic bone disease, potentially providing a noninvasive tool for the evaluation of therapies for ROD.

View details for DOI 10.1002/jmri.20085

View details for Web of Science ID 000222411900011

View details for PubMedID 15221812
Interpretation of whole body dual energy X-ray absorptiometry measures in children: comparison with peripheral quantitative computed tomography BONE Leonard, M. B., Shults, J., Elliott, D. M., Stallings, V. A., Zemel, B. S. 2004; 34 (6): 1044-1052
Abstract

The assessment of bone health in children requires strategies to minimize the confounding effects of bone size on dual energy X-ray absorptiometry (DXA) areal bone mineral density (BMD) results. Cortical bone composes 80% of the total skeletal bone mass. The objective of this study was to develop analytic strategies for the assessment of whole body DXA that describe the biomechanical characteristics of cortical bone across a wide range of body sizes using peripheral quantitative computed tomography (pQCT) measures of cortical geometry, density (mg/mm(3)), and strength as the gold standard. Whole body DXA (Hologic QDR 4500) and pQCT (Stratec XCT-2000) of the tibia diaphysis were completed in 150 healthy children 6-21 years of age. To assess DXA and pQCT measures relative to age, body size, and bone size, gender-specific regression models were used to establish z scores for DXA bone mineral content (BMC) for age, areal BMD for age, bone area for height, bone area for lean mass, BMC for height, BMC for lean mass, and BMC for bone area; and for pQCT, bone cross-sectional area (CSA) for tibia length and bone strength (stress-strain index, SSI) for tibia length. DXA bone area for height and BMC for height were both strongly and positively associated with pQCT CSA for length and with SSI for length (all P < 0.0001), suggesting that decreases in DXA bone area for height or DXA BMC for height represent narrower bones with less resistance to bending. DXA BMC for age (P < 0.01) and areal BMD (P < 0.05) for age were moderately correlated with strength. Neither DXA bone area for lean mass nor BMC for lean mass correlated with pQCT CSA for length or SSI for length. DXA BMC for bone area was weakly associated with pQCT SSI for length, in females only. Therefore, normalizing whole body DXA bone area for height and BMC for height provided the best measures of bone dimensions and strength. DXA BMC normalized for bone area and lean mass were poor indicators of bone strength.

View details for DOI 10.1016/j.bone.2003.12.003

View details for Web of Science ID 000222219600015

View details for PubMedID 15193552
Osteoporosis in chronic kidney disease AMERICAN JOURNAL OF KIDNEY DISEASES Cunningham, J., Sprague, S. M., Cannata-Andia, J., Coco, M., Cohen-Solal, M., Fitzpatrick, L., Goltzmann, D., Lafage-Proust, M. H., Leonard, M., Ott, S., Rodriguez, M., Stehman-Breen, C., Stern, P., Weisinger, J. 2004; 43 (3): 566-571
View details for DOI 10.1053/j.ajkd.2003.12.004

View details for Web of Science ID 000220538800020

View details for PubMedID 14981616
Bone disease in pediatric rheumatologic disorders. Current rheumatology reports Burnham, J. M., Leonard, M. B. 2004; 6 (1): 70-78
Abstract

Children with rheumatic disorders have multiple risk factors for impaired bone health, including delayed growth and development, malnutrition, decreased weight-bearing activity, inflammation, and glucocorticoid therapy. The impact of rheumatic disease during childhood may be immediate, resulting in fragility fractures, or delayed, because of suboptimal peak bone mass accrual. Recent years have seen increased interest in the effects of pediatric rheumatic disorders on bone mineralization, such as juvenile rheumatoid arthritis, systemic lupus erythematosus, and juvenile dermatomyositis. This review outlines the expected gains in bone size and mass during childhood and adolescence, and summarizes the advantages and disadvantages of available technologies for the assessment of skeletal growth and fragility in children. The varied threats to bone health in pediatric rheumatic disorders are reviewed, with emphasis on recent insights into the molecular mechanisms of inflammation-induced bone resorption. The literature assessing bone deficits and risk factors for impaired bone health in pediatric rheumatic disorders is reviewed, with consideration of the strengths and limitations of prior studies. Finally, future research directions are proposed.

View details for PubMedID 14713405
Assessment of bone health in children and adolescents with cancer: Promises and pitfalls of current techniques 7th International Conference on the Long-Term Complications of Treatment of Children and Adolescents for Cancer Leonard, M. B. WILEY-LISS. 2003: 198–207
Abstract

During childhood and adolescence, skeletal development is characterized by gender-, face-, and maturation-specific increases in cortical dimensions and trabecular density. Children with cancer have multiple risk factors for impuired bone mineralization, including delayed growth and maturation, sex hormone deficiencies, decreasal physical activity and biomechanical loading of the skeleton, glucocorticoid and other immunosuppressive therapies, growth hormone deficiency, and malnutrition. This review outlines the expected gains in bone dimensions, mineral content and strength during childhood and adolescence. Varied threats to bone health in the child with cancer are summarized, with special attention to potential effects on bone formation and resorption in the growing skeleton. The strengths and limitations of dual energy x-ray absorptiometry (DXA) and quantitative computed tomography (QCT) techniques in the assessment of the different disease-related effects on bone strength are discussed, and alternative analytic approaches explored.

View details for DOI 10.1002/mpo.10337

View details for Web of Science ID 000184414500005

View details for PubMedID 12868119
Calcium-free hemodialysis for hypercalcemia of malignancy in a newborn PEDIATRIC NEPHROLOGY Pradhan, M., Leonard, M. B. 2003; 18 (5): 474-476
Abstract

Hypercalcemia associated with malignancy is very rare in the newborn period. Severe hypercalcemia causes neurological and cardiological disturbances and can be life threatening. Calcium-free hemodialysis has not been reported for the treatment of malignancy associated hypercalcemia in neonates. We report a 5-day-old infant with severe hypercalcemia (serum calcium 22 mg/dl) secondary to a solid tumor in the pelvis. Aggressive pharmacological treatment with furosemide, pamidronate, and calcitonin failed to reduce the serum calcium adequately. Implementation of calcium-free hemodialysis resulted in a rapid reduction of the serum calcium from 22.6 mg/dl to 11.6 mg/dl. Hemodialysis was well tolerated with no hemodynamic complications. Continuous veno-venous hemodialysis was used to maintain normocalcemia.

View details for DOI 10.1007/s00467-003-1138-9

View details for Web of Science ID 000183186600017

View details for PubMedID 12687453
Long versus standard initial steroid therapy for children with the nephrotic syndrome - A report from the Southwest Pediatric Nephrology Study Group PEDIATRIC NEPHROLOGY Lande, M. B., Gullion, C., Hogg, R. J., Gauthier, B., Shah, B., Leonard, M. B., Bonilla-Felix, M., Nash, M., Roy, S., Strife, C. F., Arbus, G. 2003; 18 (4): 342-346
Abstract

A retrospective cohort study was conducted by the Southwest Pediatric Nephrology Study Group (SPNSG) to address whether a longer initial course of corticosteroids in patients with idiopathic nephrotic syndrome (INS) provides superior protection against relapse without increased adverse effects. In order to be included in the evaluation, patients with INS must have responded to an initial steroid course, either standard or long regimen as defined here, and completed at least 1 year of follow-up. The standard regimen consisted of prednisone 2.0+/-0.3 mg/kg per day or 60+/-10 mg/m(2) per day for 28+/-4 days, followed by alternate-day prednisone for 4-12 weeks. The long regimen consisted of daily prednisone 2.0+/-0.3 mg/kg per day or 60+/-10 mg/m(2) per day for 42+/-6 days, followed by alternate-day prednisone for 6-14 weeks. The primary outcome measure was relapse of NS within 12 months of discontinuing the initial course of prednisone. There were 151 children who met the criteria for the study; 82 received the standard regimen and 69 the long regimen. The two groups did not differ in age, race, blood pressure, serum albumin, or serum cholesterol prior to the initial steroid course. The cumulative prednisone dose was 49% higher in the long regimen group than in the standard regimen group. Relapse within 12 months was reported in 72.5% of patients who received the long regimen versus 84.1% of those who received the standard regimen. The odds ratio for relapse within 12 months was 0.496 (95% confidence interval 0.22, 1.088), long versus standard regimen. This did not reach statistical significance ( chi(2)=3.058, P=0.08). The odds ratio of experiencing at least one side effect was 3.76, long relative to standard regimen ( n=133, P<0.001). Our data suggest that prolongation of the steroid treatment for the initial episode of steroid-sensitive NS may have a beneficial effect, but at the cost of increased side effects. However, definitive conclusions are limited by the retrospective design of the study and the number of patients. This may have caused failure to achieve statistical significance on the basis of a type II error.

View details for DOI 10.1007/s00467-002-1052-6

View details for Web of Science ID 000182761800005

View details for PubMedID 12700959
A prospective cohort study of incident maintenance dialysis in children: An NAPRTC study KIDNEY INTERNATIONAL Leonard, M. B., Donaldson, L. A., Ho, M., Geary, D. F. 2003; 63 (2): 744-755
Abstract

Prior studies of dialysis practices and outcomes have included children with varied duration of end-stage renal disease (ESRD). This study evaluated dialysis characteristics, complications, practices, and outcomes in an incident pediatric cohort.The cohort was limited to 1992 subjects enrolled in the North American Pediatric Renal Transplant Cooperative Study registry, starting hemodialysis (HD) or peritoneal dialysis (PD) between 1992 and 1998, without prior dialysis or transplantation.At dialysis initiation, the median glomerular filtration rate (GFR; Schwartz formula) was 6 to 11 mL/min/1.73 m2, and 90th percentile was 14 to 25 mL/min/1.73 m2. GFR was not associated with age or race. PD was used in 97% of infants, 70 to 80% of children and 59% of adolescents. Blacks were significantly less likely to be started on PD than whites. Twenty percent of patients switched dialysis modality, largely due to infection, inadequate access or family choice. Younger children received HD almost exclusively through percutaneous catheters, while 57% of children more than six years old were dialyzed with fistula or graft after six months on HD. The prevalence of anemia (Hct <33%) still exceeded 40% after six months of dialysis. The median interval to transplantation was 1.4 years, and was significantly greater in non-white, young, and female patients. Mortality rates (deaths/1000 patient-years) varied with age, from 13.6 in infants to 2.2 in adolescents.These data demonstrate considerable variability in patient management across pediatric centers. Prospective studies are needed to determine the optimum adequacy of care among children on dialysis and to identify populations at risk.

View details for Web of Science ID 000180419300038

View details for PubMedID 12631143
Decline in renal function following thoracic organ transplantation in children AMERICAN JOURNAL OF TRANSPLANTATION Pradhan, M., Leonard, M. B., Bridges, N. D., Jabs, K. L. 2002; 2 (7): 652-657
Abstract

Heart and/or lung transplantation are life-saving treatments for end-stage cardiopulmonary disease; however, chronic renal failure may develop. The impact of thoracic organ transplant on renal function in infants and children is not well characterized. This retrospective cohort study evaluated renal function following thoracic organ transplantation in 46 children (32 heart, 9 lung, 5 heart-lung; median age 4.1 years) with at least 12 months of follow-up. Glomerular filtration rate (GFR, ml/min/1.73 m2) was estimated by the Schwartz formula throughout and each GFR estimate was converted to per cent normal for age (GFR%). Changes in renal function following transplantation were analyzed using longitudinal mixed-effects linear regression models. GFR% decreased following thoracic organ transplantation (p <0.001). Younger age at transplant was associated with a greater decline in GFR% (p <0.01). The decline in GFR% persisted after adjustment for nutritional status with body mass index or weight-for-length z-scores. The prevalence of renal insufficiency (GFR% <75) increased from 22% at transplant to 55% and 85% at 1 and 5 years post transplant, respectively, while 15% had a GFR% <50 at 5 years post transplantation. Higher tacrolimus trough levels over the first 6 months correlated with a lower GFR% (p <0.01). Renal function declined significantly following thoracic organ transplantation.

View details for Web of Science ID 000177118200011

View details for PubMedID 12201367
Current concepts in pediatric bone disease PEDIATRIC CLINICS OF NORTH AMERICA Leonard, M. B., Zemel, B. S. 2002; 49 (1): 143-?
Abstract

It is widely believed that osteoporosis prevention may be best accomplished during childhood and adolescence, when bones are growing rapidly and are most sensitive to environmental influences, such as diet and physical activity. For children with chronic diseases, a variety of factors may influence normal bone mineralization, including altered growth, delayed maturation, inflammation, malabsorption, reduced physical activity, glucocorticoid exposure, and poor dietary intake. In healthy children, maintaining adequate levels of calcium intake, serum vitamin D, and weightbearing physical activity may be sufficient to prevent osteoporosis later in life. Far less is known about effective prevention and treatment of poor bone mineralization in children with chronic illness, such as CF or CD. Osteoporosis prevention and intervention measures during childhood are limited by the paucity of reference data on bone mineralization. Although it is widely recognized that puberty, skeletal maturation, and body size influence BMC and bone density, no reference data for bone mineralization are scaled to these important measures. In children with chronic disease with delayed growth and maturation, the creation of such reference data is of paramount importance. In addition, the dynamic changes that occur during growth and maturation in the structural characteristics of trabecular and cortical bone and the development of the bone-muscle unit may influence current and future fracture risk. Further research is needed to characterize these changes and their use in the assessment of bone health and fracture risk in children. Only then can the impact of treatment strategies be appreciated fully.

View details for Web of Science ID 000173506600009

View details for PubMedID 11826803
Adverse neurologic events associated with rebound hypertension nifedipine in childhood after using short-acting in hypertension PEDIATRIC EMERGENCY CARE Leonard, M. B., Kasner, S. E., Feldman, H. I., Schulman, S. L. 2001; 17 (6): 435-437
Abstract

Short-acting nifedipine (SA-NIF) is widely prescribed for acute hypertension (HTN) in children despite reports of ischemic complications in adults. We describe two children with neurologic events caused by rebound hypertension following SA-NIF use.Patient 1 is a 7-year-old with acute nephritis and blood pressure (BP) of 185/130. She received SA-NIF which decreased BP to 114/79. When BP rebounded to 160/103, she developed severe cortical visual impairment. Head CT demonstrated edema and petechial hemorrhages in the watershed region. Patient 2 is a 10-year-old renal transplant recipient who received SA-NIF for a BP of 155/98, which resulted in a prompt decrease to 114/74. Two hours later he developed aphasia and right-sided neglect. His BP increased to 168/88 and he developed partial complex seizures. Brain MRI showed high signal intensity in the watershed areas with early gadolinium enhancement.The temporal association of the neurologic events with the rebound increase in BP suggests a possible role for the SA-NIF, consistent with its pharmacokinetic profile. Although the adult literature has focused on the unpredictable decline in BP after SA-NIF treatment, these cases suggest that rapid increases in BP following the maximal SA-NIF effect may be associated with impaired cerebral autoregulation and encephalopathy in children. These cases underscore the need for frequent blood pressure determinations and therapy to prevent rebound hypertension.

View details for Web of Science ID 000173001500008

View details for PubMedID 11753188
Early risk factors for increased adiposity: a cohort study of African American subjects followed from birth to young adulthood AMERICAN JOURNAL OF CLINICAL NUTRITION Stettler, N., Tershakovec, A. M., Zemel, B. S., Leonard, M. B., Boston, R. C., Katz, S. H., Stallings, V. A. 2000; 72 (2): 378-383
Abstract

Obesity is an increasing concern in the United States. Effective prevention of obesity requires the risk factors to be well defined. African Americans have a high risk of obesity.The objective of this study was to identify risk factors, present at birth, for increased adiposity in adulthood in an African American population.In this retrospective analysis of a prospective cohort study, anthropometric and socioeconomic variables were collected at birth. A representative sample of 447 African American subjects was followed up until young adulthood, when skinfold thickness was measured. Associations between the independent variables and increased adiposity (skinfold thickness above the 85th percentile) were explored by using unadjusted and adjusted analyses.Three variables measured at birth were independently associated with adiposity in young adulthood, explaining 12% of the variance. The odds ratios (with 95% CIs) of these variables for increased adiposity were 2.7 (1.2, 6.2) for female sex, 4.0 (1.4, 11. 2) for first-born status, and 1.15 (1.06, 1.25) for each unit increment in maternal prepregnancy body mass index (BMI; in kg/m(2)). After adjustment for these variables, birth weight for gestational age and socioeconomic variables were not associated with adiposity.This cohort study of African American subjects was the first to identify first-born status as an independent risk factor for increased adiposity in adulthood in a US population. The results of the study strengthen previous reports of the effect of female sex and maternal BMI on adulthood obesity. Identification of risk factors early in life may help target prevention toward high-risk children and allow healthy lifestyles to be established before the onset of obesity.

View details for Web of Science ID 000088565100011

View details for PubMedID 10919930
Increased urinary transforming growth factor-beta(1) excretion in children with posterior urethral valves UROLOGY Dell, K. M., Hoffman, B. B., Leonard, M. B., ZIYADEH, F. N., Schulman, S. L. 2000; 56 (2): 311-314
Abstract

Patients with posterior urethral valves (PUV) are at significant risk for progression to end-stage renal disease, despite early correction of the obstruction. Experimental models of urinary obstruction demonstrate increased renal expression of the profibrotic inflammatory mediator, transforming growth factor-beta(1) (TGF-beta(1)). Urinary TGF-beta(1) excretion is elevated in certain glomerular diseases, but has not been well studied in patients with obstructive lesions. The objective of this study was to examine urinary TGF-beta(1) excretion in children with PUV.Fourteen patients with PUV, aged 3.2 to 14.5 years, with estimated glomerular filtration rates (GFRs) of 12.8 to 139 mL/min/1.73 m(2) were enrolled. Sixteen normal subjects (9 male, 7 female), aged 4.3 to 20.5 years, served as controls. Total urinary TGF-beta(1) concentration was assayed by enzyme-linked immunoabsorbent assay, and expressed as a ratio to urinary creatinine concentration.Urinary TGF-beta(1) excretion was significantly greater in patients with PUV (range 0 to 0.063, median 0.019 ng/mg urine creatinine) compared with that of healthy controls (range 0 to 0.022, median 0.005 ng/mg urine creatinine) (P <0.01). There was no correlation between urinary TGF-beta(1) excretion and estimated GFR, past urinary diversion surgery, or bladder wall thickening. Among healthy controls, urinary TGF-beta(1) was not correlated with age or gender.Results from this study suggest that TGF-beta(1) may contribute to progressive renal insufficiency in patients with PUV. Further studies are indicated to determine if agents that affect TGF-beta(1) expression, such as angiotensin-converting enzyme inhibitors, can slow the progression of renal disease in PUV.

View details for Web of Science ID 000088574000026

View details for PubMedID 10925100
Variability among pediatric nephrologists in the initial therapy of nephrotic syndrome PEDIATRIC NEPHROLOGY Lande, M. B., Leonard, M. B. 2000; 14 (8-9): 766-769
Abstract

The objective of this study was to describe the practices of North American pediatric nephrologists in treating new-onset steroid-sensitive nephrotic syndrome and impressions regarding the effect of therapy duration on the risk of relapse. A questionnaire was mailed to 130 pediatric nephrologists in the United States and Canada. One hundred and five (81%) replied. Of the respondents, 39% believed a longer steroid regimen results in more-sustained remissions; 19% did not; 18% believed perhaps, but not enough to risk the increased side-effects of the longer steroid regimen; and 24% did not know. Half of the respondents prescribed an 8-week regimen and 21% prescribed a 12-week regimen; however, in 70% of both regimens, respondents appended an additional taper. The remaining respondents either tapered at urinary remission (14%) or used another regimen (15%). Physicians using the 12-week regimen expected 44% of patients to be relapse free at 1 year, compared with 31% of patients of respondents using other regimens (P=0.005). Over the previous 5 years, 38% of respondents changed their approach; of these, 70% lengthened the treatment course. Physician perceptions and strategies did not vary according to years of clinical experience. In conclusion, there is significant variability in practice and perceptions among pediatric nephrologists; however, most have extended therapy beyond the traditional 8-week course.

View details for Web of Science ID 000088695900013

View details for PubMedID 10955923
Discrepancies in pediatric bone mineral density reference data: Potential for misdiagnosis of osteopenia JOURNAL OF PEDIATRICS Leonard, M. B., PROPERT, K. J., Zemel, B. S., Stallings, V. A., Feldman, H. I. 1999; 135 (2): 182-188
Abstract

To evaluate published pediatric dual-energy x-ray absorptiometry bone mineral density (BMD) reference data by comparing the diagnostic classification of measured BMD in children at risk for osteopenia as healthy or osteopenic according to reference source.Spine BMD was measured in 95 children, ages 9 to 15 years, at risk for osteopenia because of childhood disease. The BMD results were converted to age-specific z scores for each of the 5 reference data sets, and the z -score distributions were compared.Between 11% and 30% of children were classified as osteopenic (z score < -2.0) depending on the reference data set. The 2 sex-specific reference data sets yielded similar diagnostic classification of boys and girls: 10% of boys and 11% to 16% of girls were osteopenic (P =.4). The 3 sex-nonspecific reference data sets classified 9% to 13% of girls and 24% to 44% of boys as osteopenic; the diagnosis of osteopenia was significantly greater in boys (P <.01).The use of different published reference data for the assessment of children at risk for osteopenia results in inconsistent diagnostic classification of BMD results. These inconsistencies can be partially attributed to sex-nonspecific reference data that result in misclassification of boys as osteopenic.

View details for Web of Science ID 000081885900011

View details for PubMedID 10431112
Evaluation of low density spine software for the assessment of bone mineral density in Children 19th Annual Meeting of the American-Society-for-Bone-and-Mineral-Research Leonard, M. B., Feldman, H. I., Zemel, B. S., Berlin, J. A., Barden, E. M., Stallings, V. A. WILEY-BLACKWELL. 1998: 1687–90
Abstract

Pediatric dual-energy X-ray absorptiometry spine scans often cannot be analyzed with standard software due to a failure to identify the bone edges of low density vertebrae. Low density spine (LDS) software improves bone detection compared with standard software. The objective of this study was to compare bone mineral density (BMD) measurements obtained with the standard and LDS software in 27 healthy nonobese, 32 obese, and 41 chronically ill children, ages 2-18 years. Lumbar spine (L1-L4) BMD, measured by standard analysis, ranged from 0.531-1.244 gm/cm2. Reanalysis with the LDS software resulted in a systematic increase (mean +/- SD) in estimated bone area of 17.0+/-5.0%, an increase in bone mineral content of 6.1+/-6.3%, and a mean decrease in BMD of 8.7+/-1.7% (all p < 0.001). This resulted in a mean decrease in BMD Z score of 0.7+/-0.2. Linear regression models, predicting standard BMD from LDS BMD, were fit for the three subject groups (R2 = 0.993-0.995). Small differences in slopes were detected across groups (p = 0.07); LDS BMD predicted higher standard BMD in obese subjects. In conclusion, LDS analysis resulted in a clinically significant decrease in measured BMD. The association between analysis methods was exceptionally high (R2 > 0.99), indicating that LDS BMD accurately predicts standard BMD. Although LDS BMD in obese subjects predicts higher standard BMD results than in nonobese subjects, the small difference is of questionable clinical significance. LDS software is a useful tool for the assessment of BMD in children.

View details for Web of Science ID 000076526500007

View details for PubMedID 9797476
Interaction between tacrolimus and chloramphenicol in a renal transplant recipient TRANSPLANTATION Schulman, S. L., Shaw, L. M., Jabs, K., Leonard, M. B., Brayman, K. L. 1998; 65 (10): 1397-1398
Abstract

The metabolism of tacrolimus is influenced by several medications when they are given concurrently. We report the interaction between tacrolimus and chloramphenicol in a renal transplant recipient.An adolescent with vancomycin-resistant Enterococcus was given standard doses of chloramphenicol. Tacrolimus trough levels increased, and the dose was adjusted to maintain the target trough level. Pharmacokinetic studies were obtained during chloramphenicol administration and 14 days after its discontinuation.Toxic levels of tacrolimus were seen on the second day of chloramphenicol administration, requiring an 83% reduction in the tacrolimus dose. The dose-adjusted area under the curve value for tacrolimus was 7.5-fold greater while the patient was on chloramphenicol. These data are consistent with inhibition of tacrolimus clearance by chloramphenicolChloramphenicol interferes with tacrolimus metabolism. Careful monitoring of tacrolimus trough levels during concomitant chloramphenicol therapy is recommended to avoid toxicity.

View details for Web of Science ID 000073990700020

View details for PubMedID 9625026
Plasma zinc status, growth, and maturation in children with sickle cell disease JOURNAL OF PEDIATRICS Leonard, M. B., Zemel, B. S., Kawchak, D. A., Ohene-Frempong, K., Stallings, V. A. 1998; 132 (3): 467-471
Abstract

The objective of this study was to determine the relation of plasma zinc (Zn) status to growth and maturation in children with SS genotype sickle cell disease.A cross-sectional study of 104 subjects who were 50% female and ranged in age from 0.4 to 18 years was performed. Measures included plasma Zn concentration (Znp), height, weight, skinfold thicknesses, elbow breadth, upper arm muscle area, and fat-free mass and fat mass by total body electrical conductivity. Skeletal maturation was assessed by hand-wrist x-ray evaluation and sexual maturation by Tanner stage.A total of 44% of the patients had low Znp (<10.7 micromol/L [70 microg/dl]); those with low Znp had significantly lower SD scores for height (p = 0.003), weight (p = 0.003), upper arm muscle area (p = 0.045), fat-free mass (p = 0.025), and elbow breadth (p = 0.017) and greater skeletal maturation delay (p = 0.04). In older children (>9 years) low Znp was associated with decreased Tanner scores for pubic hair (p = 0.001) and breast and genital maturation (p = 0.009). No significant differences were seen in age, sex, or fat stores according to Zn status.Decreased plasma Zn is common in children with SS genotype sickle cell disease and is associated with decreased linear growth, skeletal growth, muscle mass, and sexual and skeletal maturation.

View details for Web of Science ID 000072877800022

View details for PubMedID 9544903
CONTINUOUS PARENTERAL INFUSION OF VITAMIN-E PHARMACOKINETICS AND BILIRUBIN PRODUCTION IN PREMATURE NEONATES ANNALS OF THE NEW YORK ACADEMY OF SCIENCES Stevenson, D. K., Vreman, H. J., Ferguson, J. E., Lenert, L. A., Leonard, M. B., Gale, R. 1989; 570: 352-357
Abstract

We conclude that 5 mg/kg of vitamin E, administered intra-arterially as an 8-hour continuous infusion, significantly and predictably raises serum vitamin E levels into the supraphysiologic range with no apparent side effects. In a group of premature infants whose initial serum vitamin E levels were generally greater than or equal to 0.5 mg/dL, no decrease in bilirubin production was observed. Thus, vitamin E deficiency probably does not play a prominent role in jaundice of prematurity.

View details for Web of Science ID A1989CV07100032

View details for PubMedID 2629604
VANCOMYCIN PHARMACOKINETICS IN VERY LOW BIRTH-WEIGHT NEONATES PEDIATRIC INFECTIOUS DISEASE JOURNAL Leonard, M. B., Koren, G., Stevenson, D. K., Prober, C. G. 1989; 8 (5): 282-286
Abstract

The pharmacokinetics of vancomycin hydrochloride was studied in 12 very low birth weight infants. The gestational age (mean +/- SD) was 25.9 +/- 1.3 weeks and body weight was 769.2 +/- 151.5 g at the time of initiation of the study. Vancomycin was infused over a period of 60 minutes in a dosage of 14.2 +/- 3.2 mg/kg once daily in 10 patients, twice daily in 1 patient and every 36 hours in 1 patient for a mean of 10.5 +/- 4.9 days. Serial blood samples were obtained and the concentration time data were fitted to a one-compartment open model using the ADAPT computer program. A significant positive correlation was found between postconceptional age and vancomycin clearance (P less than 0.005) and between vancomycin elimination half-life and plasma creatinine (P less than 0.01). A negative correlation existed between plasma creatinine and vancomycin clearance (P less than 0.005), between postconceptional age and plasma creatinine (P less than 0.005) and between vancomycin half-life and postconceptional age (P less than 0.01). On the basis of these findings a vancomycin dosage of 15 mg/kg every 24 hours for infants less than 1000 g should yield concentrations within the accepted therapeutic range. This susceptible population requires frequent monitoring of vancomycin concentrations because of the high degree of interpatient variability and the continuous maturation of renal function.

View details for Web of Science ID A1989U613900006

View details for PubMedID 2657617
INTERPRETING THE CARBOXYHEMOGLOBIN CONCENTRATION IN FETAL CORD BLOOD JOURNAL OF DEVELOPMENTAL PHYSIOLOGY Leonard, M. B., Vreman, H. J., Ferguson, J. E., Smith, D. W., Stevenson, D. K. 1989; 11 (2): 73-76
Abstract

We calculated the fetal-to-maternal carboxyhaemoglobin concentration ratio in 19 mother-infant pairs at the time of term delivery. Mothers, who had a less than 10% drop in their carboxyhaemoglobin concentration during labour, had an average ratio of 1.40 +/- 0.19. For mothers whose carboxyhaemoglobin concentrations dropped by 10% or more during labour, the average fetal-to-maternal carboxyhaemoglobin concentration ratio was 1.83 +/- 0.48. There was a strong correlation (r = 0.82) between the percent change in maternal carboxyhaemoglobin concentration during labour and the fetal-to-maternal carboxyhaemoglobin concentration ratio at the time of delivery. We conclude that increased CO elimination during labour may be accompanied by rapid changes in the maternal carboxyhaemoglobin concentration, leading to a spuriously high fetal-to-maternal carboxyhemoglobin concentration ratio at the time of delivery.

View details for Web of Science ID A1989AJ93800003

View details for PubMedID 2778293
CONTINUOUS PARENTERAL INFUSION OF VITAMIN-E PHARMACOKINETICS AND BILIRUBIN PRODUCTION IN PREMATURE NEONATES CONF ON VITAMIN E : BIOCHEMISTRY AND HEALTH IMPLICATIONS Stevenson, D. K., Vreman, H. J., Ferguson, J. E., Lenert, L. A., Leonard, M. B., Gale, R. NEW YORK ACAD SCIENCES. 1989: 352–357
View details for Web of Science ID A1989BQ32R00032
THE FETAL TO MATERNAL CARBOXYHEMOGLOBIN (HBCO) RATIO AS A PREDICTOR OF NEONATAL JAUNDICE Leonard, M. B., Vreman, H. J., Ferguson, J. E., Stevenson, D. K. SLACK INC. 1987: A235–A235
View details for Web of Science ID A1987F528501362

Mary Leonard, M.D., M.S.C.E., Arline and Pete Harman Professor and Chair, Department of Pediatrics

Arline and Pete Harman Professor and Professor of Medicine (Nephrology) and, by courtesy, of Health Research and Policy (Epidemiology)

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