Research & Scholarship
The EARN-Health Trial of Financial Savings and Health
The current literature in social epidemiology and public health suggests that low financial savings has an unsurprising negative relationship with subjective well-being, and increases the odds of making visits to a healthcare provider, receiving a chronic disease diagnosis, and experiencing medical disability. Earn.org is a community-based non-profit based in San Francisco with a mission to help low-income workers build lifelong savings habits and financial capability. The organization is one of the largest providers of "goal-based savings accounts" or "matched savings accounts" in the US. The investigators propose to conduct a randomized controlled trial to determine the health effects of Earn's savings program. Through this trial, the investigators will test three principal hypotheses: (1) Participants in the Earn account, as compared to a control group, are hypothesized to demonstrate improved scores on mental health scales assessing depression and anxiety. (2) Participants in the Earn account, as compared to a control group, are hypothesized to experience lower odds of harmful behaviors associated with stress, specifically tobacco and alcohol abuse. The investigators hypothesize that the effect on behaviors will be of smaller effect size, and more delayed, than the effect on mental health outcomes, judging from similar effects observed in the micro-credit literature. (3) The mediating variables between Earn account participation and beneficial health outcomes will include increased optimism and internal locus of control.
Stanford is currently not accepting patients for this trial. For more information, please contact Sanjay Basu, (415) 881 - 7030.
Social and biological influences on Aging in Costa Rica, Stanford University
Research on DNA methylation has uncovered remarkable correlations with age, far stronger than previous putative biomarkers of aging. Although these findings are promising, it remains unknown whether DNA methylation patterns contribute to population differences in healthy aging and longevity. To address this question, we will build on our prior work in the demographically well-defined high longevity population of the Nicoya Peninsula in Costa Rica, to identify key DNA methylation signatures underlying the low levels of frailty and high longevity of this population. We will build on prior characterizations of DNA methylation associated with aging to support our central hypothesis that environmental exposures become biologically encoded in DNA methylation and have important associations with healthy aging. We will then examine how these identified signatures relate to healthy aging in Canada. The innovation of this proposal is that we will be analyzing differences in DNA methylation profiles that are modifiable by the environment and characteristic of a population.
Statistical learning about inequality in healthy aging from a large population based study: the CONSTANCES cohort
Profs. Marcel Goldberg and Marie Zins are leading one of the largest detailed population based cohorts to date in the CONSTANCES cohort in France. While currently in the United States the largest population based cohort to study the social, economic and genetic factors influencing healthy aging is the Health and Retirement Study which has a sample size of around 25,000 for most samples, the CONSTANCES cohort follows 200,000 individuals, with even more detailed socioeconomic, geographic and biological data than the most comparable U.S. studies. The unprecedented size and comprehensiveness of the CONSTANCES cohort will allow fundamentally new discoveries in terms of isolated effects within population subgroups and higher order interactions. Many of the statistical methods to achieve these discoveries have been developed by faculty in the Statistics department at Stanford University and other members of the Stanford faculty are leaders in the application of these methods. The proposed project will foster a collaboration of the application of machine learning methods for examining heterogeneity of treatment effects in the CONSTANCES cohort. In addition, learning about the implementation and promise of very large, detailed cohort studies will inform the early stages of related research efforts in the United States, such as the newly proposed Precision Medicine Initiative cohort of 1,000,000 individuals.
- Life Course Epidemiology
HRP 267 (Aut)
- Why do the French live so long?
OSPPARIS 49 (Win)
Independent Studies (8)
- Directed Reading in Health Research and Policy
HRP 299 (Aut, Win, Spr, Sum)
- Directed Reading in Medicine
MED 299 (Aut, Win, Spr)
- Early Clinical Experience in Medicine
MED 280 (Win, Spr)
- Graduate Research
HRP 399 (Aut, Win, Spr, Sum)
- Graduate Research
MED 399 (Aut, Win, Spr)
- Independent Study on Influences on Health in France
OSPPARIS 46 (Win)
- Medical Scholars Research
MED 370 (Aut, Win, Spr, Sum)
- Undergraduate Research
MED 199 (Aut, Win, Spr)
- Directed Reading in Health Research and Policy
- Prior Year Courses
Master's Program Advisor
- A New Tool for Case Studies in Epidemiology-the Synthetic Control Method. Epidemiology (Cambridge, Mass.) 2018; 29 (4): 503–5
The impact of a private sector living wage intervention on consumption and cardiovascular disease risk factors in a middle income country
BMC PUBLIC HEALTH
2018; 18: 179
A positive association of socioeconomic position and health is well established in high-income countries. In poorer nations, however, higher income individuals often have more cardiovascular risk factors (including obesity) than do those with less income. Our study goal was to estimate the effects of receiving a living wage (340% higher income) on short-term changes in consumption and cardiovascular risk factors among low-wage workers in a middle-income country.This cross-sectional study matched workers at an apparel factory (n=105) in the Dominican Republic with those at a similar factory (n=99) nearby, 15 months after the intervention factory introduced a substantially higher living wage. Statistical matching on non-time varying individual characteristics (childhood health, childhood living conditions, work experience, demographic factors) strengthened causal inference. Primary outcomes were blood pressure (systolic and diastolic), pulse rate, body mass index and waist circumference. Secondary outcomes were dietary consumption and spending on services, consumables and durable goods.Receiving the living wage was associated with increased consumption of protein, dairy, soda and juice and sugars, but not with cardiovascular risk factors. Intervention factory workers spent more on grocery items and household durable goods.While having a higher income in a middle-income country might be expected to increase obesity and its associated health risks, the current study found no short-term negative associations. There may be possible longer-term negative health consequences of increases in consumption of soda, juice and sugars, however. It is important to consider complementary interventions to support healthy dietary intake in areas with increasing wages.
View details for DOI 10.1186/s12889-018-5052-2
View details for Web of Science ID 000423405200003
View details for PubMedID 29370797
View details for PubMedCentralID PMC5785889
Differential DNA methylation and lymphocyte proportions in a Costa Rican high longevity region
EPIGENETICS & CHROMATIN
The Nicoya Peninsula in Costa Rica has one of the highest old-age life expectancies in the world, but the underlying biological mechanisms of this longevity are not well understood. As DNA methylation is hypothesized to be a component of biological aging, we focused on this malleable epigenetic mark to determine its association with current residence in Nicoya versus elsewhere in Costa Rica. Examining a population's unique DNA methylation pattern allows us to differentiate hallmarks of longevity from individual stochastic variation. These differences may be characteristic of a combination of social, biological, and environmental contexts.In a cross-sectional subsample of the Costa Rican Longevity and Healthy Aging Study, we compared whole blood DNA methylation profiles of residents from Nicoya (n = 48) and non-Nicoya (other Costa Rican regions, n = 47) using the Infinium HumanMethylation450 microarray.We observed a number of differences that may be markers of delayed aging, such as bioinformatically derived differential CD8+ T cell proportions. Additionally, both site- and region-specific analyses revealed DNA methylation patterns unique to Nicoyans. We also observed lower overall variability in DNA methylation in the Nicoyan population, another hallmark of younger biological age.Nicoyans represent an interesting group of individuals who may possess unique immune cell proportions as well as distinct differences in their epigenome, at the level of DNA methylation.
View details for DOI 10.1186/s13072-017-0128-2
View details for Web of Science ID 000400745800001
View details for PubMedID 28465725
Social, Psychological, And Physical Aspects Of The Work Environment Could Contribute To Hypertension Prevalence.
2017; 36 (2): 258-265
Studies on the physical and social characteristics of the workplace have begun to provide evidence for the role of specific workplace factors on health. However, the overall contribution of the workplace to health has not been considered. Estimates of the influences on health across domains of the work environment are a critical first step toward understanding what level of priority the workplace should take as the target for public policies to improve health. The influences or contribution of these domains on health in the work environment are particularly useful to study since they are potentially modifiable through changes in policies and environment. Our analysis used detailed data from blue-collar industrial workers at two dozen Alcoa plants. It includes work environmental measures of psychological hazards, physical hazards, and the workplace social environment, to estimate the overall importance of the workplace environment for hypertension. Our findings suggest that social, psychological, and physical aspects of the work environment could contribute to a substantial proportion of hypertension prevalence. These attributes of the workplace could thus be a useful target for improving workforce health.
View details for DOI 10.1377/hlthaff.2016.1186
View details for PubMedID 28167714
Leukocyte Telomere Length in Relation to 17 Biomarkers of Cardiovascular Disease Risk: A Cross-Sectional Study of US Adults
2016; 13 (11)
Leukocyte telomere length (LTL) is a putative biological marker of immune system age, and there are demonstrated associations between LTL and cardiovascular disease. This may be due in part to the relationship of LTL with other biomarkers associated with cardiovascular disease risk. However, the strength of associations between LTL and adiposity, metabolic, proinflammatory, and cardiovascular biomarkers has not been systematically evaluated in a United States nationally representative population.We examined associations between LTL and 17 cardiovascular biomarkers, including lipoproteins, blood sugar, circulatory pressure, proinflammatory markers, kidney function, and adiposity measures, in adults ages 20 to 84 from the cross-sectional US nationally representative 1999-2002 National Health and Nutrition Examination Survey (NHANES) (n = 7,252), statistically adjusting for immune cell type distributions. We also examine whether these associations differed systematically by age, race/ethnicity, gender, education, and income. We found that a one unit difference in the following biomarkers were associated with kilobase pair differences in LTL: BMI -0.00478 (95% CI -0.00749--0.00206), waist circumference -0.00211 (95% CI -0.00325--0.000969), percentage of body fat -0.00516 (95% CI -0.00761--0.0027), high density lipoprotein (HDL) cholesterol 0.00179 (95% CI 0.000571-0.00301), triglycerides -0.000285 (95% CI -0.000555--0.0000158), pulse rate -0.00194 (95% CI -0.00317--0.000705), C-reactive protein -0.0363 (95% CI 0.0601--0.0124), cystatin C -0.0391 (95% CI -0.0772--0.00107). When using clinical cut-points we additionally found associations between LTL and insulin resistance -0.0412 (95% CI -0.0685--0.0139), systolic blood pressure 0.0455 (95% CI 0.00137-0.0897), and diastolic blood pressure -0.0674 (95% CI -0.126--0.00889). These associations were 10%-15% greater without controlling for leukocyte cell types. There were very few differences in the associations by age, race/ethnicity, gender, education, or income. Our findings are relevant to the relationships between these cardiovascular biomarkers in the general population but not to cardiovascular disease as a clinical outcome.LTL is most strongly associated with adiposity, but is also associated with biomarkers across several physiological systems. LTL may thus be a predictor of cardiovascular disease through its association with multiple risk factors that are physiologically correlated with risk for development of cardiovascular disease. Our results are consistent with LTL being a biomarker of cardiovascular aging through established physiological mechanisms.
View details for DOI 10.1371/journal.pmed.1002188
View details for Web of Science ID 000391233800024
View details for PubMedID 27898678
View details for PubMedCentralID PMC5127504
The Geographic Distribution of Genetic Risk as Compared to Social Risk for Chronic Diseases in the United States
BIODEMOGRAPHY AND SOCIAL BIOLOGY
2016; 62 (1): 126-142
There is an association between chronic disease and geography, and there is evidence that the environment plays a critical role in this relationship. Yet at the same time, there is known to be substantial geographic variation by ancestry across the United States. Resulting geographic genetic variation-that is, the extent to which single nucleotide polymorphisms (SNPs) related to chronic disease vary spatially-could thus drive some part of the association between geography and disease. We describe the variation in chronic disease genetic risk by state of birth by taking risk SNPs from genome-wide association study meta-analyses for coronary artery disease, diabetes, and ischemic stroke and creating polygenic risk scores. We compare the amount of variability across state of birth in these polygenic scores to the variability in parental education, own education, earnings, and wealth. Our primary finding is that the polygenic risk scores are only weakly differentially distributed across U.S. states. The magnitude of the differences in geographic distribution is very small in comparison to the distribution of social and economic factors and thus is not likely sufficient to have a meaningful effect on geographic disease differences by U.S. state.
View details for DOI 10.1080/19485565.2016.1141353
View details for Web of Science ID 000373629600008
View details for PubMedID 27050037
- Early-Life State-of-Residence Characteristics and Later Life Hypertension, Diabetes, and Ischemic Heart Disease AMERICAN JOURNAL OF PUBLIC HEALTH 2015; 105 (8): 1689-1695
Systematic assessment of the correlations of household income with infectious, biochemical, physiological, and environmental factors in the United States, 1999-2006.
American journal of epidemiology
2015; 181 (3): 171-179
A fuller understanding of the social epidemiology of disease requires an extended description of the relationships between social factors and health indicators in a systematic manner. In the present study, we investigated the correlations between income and 330 indicators of physiological, biochemical, and environmental health in participants in the US National Health and Nutrition Examination Survey (NHANES) (1999-2006). We combined data from 3 survey waves (n = 249-23,649 for various indicators) to search for linear and nonlinear (quadratic) correlates of income, and we validated significant (P < 0.00015) correlations in an independent testing data set (n = 255-7,855). We validated 66 out of 330 factors, including infectious (e.g., hepatitis A), biochemical (e.g., carotenoids, high-density lipoprotein cholesterol), physiological (e.g., upper leg length), and environmental (e.g., lead, cotinine) measures. We found only a modest amount of association modification by age, race/ethnicity, and gender, and there was no association modification for blacks. The present study is descriptive, not causal. We have shown in our systematic investigation the crucial place income has in relation to health risk factors. Future research can use these correlations to better inform theory and studies of pathways to disease, as well as utilize these findings to understand when confounding by income is most likely to introduce bias.
View details for DOI 10.1093/aje/kwu277
View details for PubMedID 25589242
View details for PubMedCentralID PMC4312426
The short-term impacts of Earned Income Tax Credit disbursement on health
INTERNATIONAL JOURNAL OF EPIDEMIOLOGY
2014; 43 (6): 1884-1894
There are conflicting findings regarding long- and short-term effects of income on health. Whereas higher average income is associated with better health, there is evidence that health behaviours worsen in the short-term following income receipt.Prior studies revealing such negative short-term effects of income receipt focus on specific subpopulations and examine a limited set of health outcomes.The United States Earned Income Tax Credit (EITC) is an income supplement tied to work, and is the largest poverty reduction programme in the USA. We utilize the fact that EITC recipients typically receive large cash transfers in the months of February,March and April, in order to examine associated changes in health outcomes that can fluctuate on a monthly basis. We examine associations with 30 outcomes in the categories of diet, food security, health behaviours, cardiovascular biomarkers, metabolic biomarkers and infection and immunity among 6925 individuals from the U.S. National Health and Nutrition Survey. Our research design approximates a natural experiment,since whether individuals were sampled during treatment or non-treatment months is independent of social, demographic and health characteristics that do not vary with time.There are both beneficial and detrimental short-term impacts of income receipt.Although there are detrimental impacts on metabolic factors among women, most other impacts are beneficial, including those for food security, smoking and trying to lose weight.The short-term impacts of EITC income receipt are not universally health promoting, but on balance there are more health benefits than detriments.
View details for DOI 10.1093/ije/dyu172
View details for Web of Science ID 000348575500032
View details for PubMedID 25172139
The relative importance of predictors of body mass index change, overweight and obesity in adolescent girls
INTERNATIONAL JOURNAL OF PEDIATRIC OBESITY
2011; 6 (2-2): E233-E242
To determine the relative importance of familial, dietary, behavioral, psychological and social risk factors for predicting body mass index (BMI) change, and onset of overweight and obesity among adolescent girls.Data from the NHLBI Growth and Health Study (n = 2 150), a longitudinal cohort of girls, were used to identify the most important predictors of change in BMI percentile between the ages of 9 and 19 years, and second, risk for becoming overweight and obese. Forty-one baseline predictors were assessed using a tree-based regression method (Random forest) to rank the relative importance of risk factors.The five factors that best predicted change in BMI percentile (p < 0.05) were related to family socio-economic position (income and parent education) and drive to restrict eating and weight (body dissatisfaction, drive for thinness and unhappiness with physical appearance). The factors that were statistically significant (p < 0.05) predictors of both onset of overweight and obesity were income, ineffectiveness and race.Family socio-economic position and emotion regulation appeared as the top predictors of both BMI change and onset of overweight and obesity. Our results build upon prior findings that policies to prevent the onset of obesity during adolescence be targeted towards girls from lower socio-economic position households. Our findings also suggest several novel psychological factors including ineffectiveness as predictors of obesity during adolescence. These predictive findings offer a direction for future inquiry into adolescent obesity etiology using causal methods.
View details for DOI 10.3109/17477166.2010.545410
View details for Web of Science ID 000292704500028
View details for PubMedID 21244233
- Effects of Prenatal Poverty on Infant Health: State Earned Income Tax Credits and Birth Weight AMERICAN SOCIOLOGICAL REVIEW 2010; 75 (4): 534-562
Gender, Depression, and Blue-collar Work: A Retrospective Cohort Study of US Aluminum Manufacturers.
Epidemiology (Cambridge, Mass.)
2019; 30 (3): 435–44
BACKGROUND: Industrial blue-collar workers face multiple work-related stressors, but evidence regarding the burden of mental illness among today's blue-collar men and women remains limited.METHODS: In this retrospective cohort study, we examined health and employment records for 37,183 blue- and white-collar workers employed by a single US aluminum manufacturer from 2003 to 2013. Using Cox proportional hazards regression, we modeled time to first episode of treated depression by gender and occupational class. Among cases, we modeled rates of depression-related service utilization with generalized gamma regression.RESULTS: Compared with their white-collar counterparts, blue-collar men were more likely to be treated for depression (hazard ratio [HR] = 1.3; 95% confidence interval [CI] = 1.1, 1.4) as were blue-collar women (HR = 1.4; 1.2, 1.6). Blue-collar women were most likely to be treated for depression as compared with white-collar men (HR = 3.2; 95% CI = 2.1, 5.0). However, blue-collar workers used depression-related services less frequently than their white-collar counterparts among both men (rate ratio = 0.91; 95% CI = 0.84, 0.98) and women (rate ratio = 0.82; 95% CI = 0.77, 0.88).CONCLUSIONS: Blue-collar women were more likely to be treated for depression than white-collar workers, and blue-collar women were most likely to be treated for depression compared with white-collar men. However, blue-collar men and women used depression-related healthcare services less frequently than white-collar workers. These findings underscore that blue-collar women may be uniquely susceptible to depression, and suggest that blue-collar workers may encounter barriers to care-seeking related mental illness other than their insurance status.
View details for DOI 10.1097/EDE.0000000000000993
View details for PubMedID 30964814
Life-course BMI and biomarkers in persons aged 60 years or older: a comparison of the USA and Costa Rica
PUBLIC HEALTH NUTRITION
2019; 22 (2): 314–23
There is a large literature linking current BMI to levels of cardiovascular risk biomarkers, but it is unknown whether measures of BMI earlier in the life course and maximum BMI are predictive of current levels of biomarkers. The objective of the current study was to determine how current, maximum and age-25 BMI among individuals over the age of 60 years are associated with their current levels of cardiovascular risk biomarkers.Cross-sectional study with retrospective recall.Costa Rica (n 821) and the USA (n 4110).Nationally representative samples of adults aged 60 years or over.We used regression models to examine the relationship between multiple meaures of BMI with four established cardiovascular risk biomarkers. The most consistent predictor of current levels of systolic blood pressure, TAG and HDL-cholesterol was current BMI. However, maximum BMI was the strongest predictor of glycosylated Hb (HbA1c) and was also related to HDL-cholesterol and TAG. HbA1c was independent of current BMI. We found that these relationships are consistent between Costa Rica and the USA for HbA1c and for HDL-cholesterol.Current levels of cardiovascular risk biomarkers are not only the product of current levels of BMI, but also of maximum lifetime BMI, particularly for levels of HbA1c and for HDL-cholesterol. Managing maximum obtained BMI over the life course may be most critical for maintaining the healthiest levels of cardiovascular risk.
View details for DOI 10.1017/S1368980018002276
View details for Web of Science ID 000458515400013
View details for PubMedID 30306887
View details for PubMedCentralID PMC6351185
Similarities in Maternal Weight and Birth Weight Across Pregnancies and Across Sisters
MATERNAL AND CHILD HEALTH JOURNAL
2019; 23 (2): 138–47
Objectives The current study examined how prepregnancy body mass index (BMI), gestational weight gain, and birth weight cluster between births within women and between women who are sisters. Methods Using data from the National Longitudinal Survey of Youth 1979 cohort, we utilized nested, multivariable hierarchical linear models to examine the correlation of these three outcomes between births (n = 6006) to women (n = 3605) and sisters (n = 3170) so that we can quantify the clustering by sibship and by woman for these three pregnancy-related outcomes. Results After controlling for confounding covariates, prepregnancy BMI (intraclass correlation (ICC) 0.24, 95% CI 0.16, 0.32), gestational weight gain (ICC 0.23, 95% CI 0.16, 0.31), and infant's birthweight (ICC 0.07, 95% CI 0.003, 0.13) were correlated between sisters. Additionally, all three outcomes were significantly correlated between births for each sister, suggesting that prepregnancy BMI (ICC 0.82, 95% CI 0.81, 0.83), gestational weight gain (ICC 0.45, 95% CI 0.42, 0.49), and birth weight (ICC 0.31, 95% CI 0.28, 0.35) track between pregnancies in the same woman. Conclusions for Practice The observed clustering both within women and between sisters suggests that shared genetic and environmental factors among sisters play a role in pregnancy outcomes above and beyond that of women's own genetic and environmental factors. Findings suggest that asking a woman about her sisters' pregnancy outcomes could provide insight into the possible outcomes for her current pregnancy. Future research should test if collecting such a family history and providing tailored clinical recommendations accordingly would be useful.
View details for DOI 10.1007/s10995-018-2602-2
View details for Web of Science ID 000459576000001
View details for PubMedID 30032445
Estimating the Short-Term Effects of the Earned Income Tax Credit on Child Health
AMERICAN JOURNAL OF EPIDEMIOLOGY
2018; 187 (12): 2633–41
The Earned Income Tax Credit (EITC) is the largest US poverty-alleviation program, yet few studies examine its effects on the health of recipients' children. We employed quasiexperimental techniques to test the hypothesis that EITC refund receipt is associated with short-term improvements in child health. The data set included children in families surveyed in the Third National Health and Nutrition Examination Survey (n = 7,444). We employed a difference-in-differences approach, exploiting the seasonal nature of EITC refund receipt. We compared children of EITC-eligible families interviewed immediately after refund receipt (February to April) with those interviewed during other months (May to January), differencing out seasonal variation among non-EITC-eligible families. We examined outcomes that were likely to be affected immediately after refund receipt, including general health, nutrition, metabolic and inflammatory biomarkers, and test scores. There were improvements in physician-reported overall health after refund receipt but no changes in infection, serum metabolic or inflammatory markers, or test scores, and there were contradictory findings for food insufficiency. In summary, EITC refunds are not strongly associated with most short-term health outcomes among recipients' children, although numerous previous studies have demonstrated impacts on longer-term outcomes. This highlights the importance of examining the effects of public policies on beneficiaries and their children using varying study designs.
View details for DOI 10.1093/aje/kwy179
View details for Web of Science ID 000453091000017
View details for PubMedID 30188968
View details for PubMedCentralID PMC6269248
Socioeconomic Differences in the Epidemiologic Transition From Heart Disease to Cancer as the Leading Cause of Death in the United States, 2003 to 2015: An Observational Study.
Annals of internal medicine
Background: Recent data suggest that the United States is in the midst of an epidemiologic transition in the leading cause of death.Objective: To examine county-level sociodemographic differences in the transition from heart disease to cancer as the leading cause of death in the United States.Design: Observational study.Setting: U.S. death records, 2003 to 2015.Participants: Decedents aged 25 years or older, classified by racial/ethnic group.Measurements: All-cause, heart disease, and cancer mortality stratified by quintiles of county median household income. Age- and sex-adjusted mortality rates and average annual percentage of change were calculated.Results: Heart disease was the leading cause of death in 79% of counties in 2003 and 59% in 2015. Cancer was the leading cause of death in 21% of counties in 2003 and 41% in 2015. The shift to cancer as the leading cause of death was greatest in the highest-income counties. Overall, heart disease mortality rates decreased by 28% (30% in high-income counties vs. 22% in low-income counties) from 2003 to 2015, and cancer mortality rates decreased by 16% (18% in high-income counties vs. 11% in low-income counties). In the lowest-income counties, heart disease remained the leading cause of death among all racial/ethnic groups, and improvements were smaller for both heart disease and cancer.Limitation: Use of county median household income as a proxy for socioeconomic status.Conclusion: Data show that heart disease is more likely to be the leading cause of death in low-income counties. Low-income counties have not experienced the same decrease in mortality rates as high-income counties, which suggests a later transition to cancer as the leading cause of death in low-income counties.Primary Funding Source: National Institute on Minority Health and Health Disparities.
View details for DOI 10.7326/M17-0796
View details for PubMedID 30422275
The association of early life socioeconomic position on breast cancer incidence and mortality: a systematic review
INTERNATIONAL JOURNAL OF PUBLIC HEALTH
2018; 63 (7): 787–97
We conducted a systematic review of the literature relating early life socioeconomic position (SEP) to breast cancer incidence and mortality from a critical period and life-course trajectory perspective.PubMed, EMBASE and Web of Science were searched to identify cohort studies that evaluated the impact of early life SEP indicators on the incidence and/or mortality from breast cancer in adulthood.Nine distinct studies evaluated the relationship between early life SEP and breast cancer between 1990 and 2016. Five reports assessed breast cancer incidence and five assessed breast cancer mortality as outcomes; one study assessed both incidence and mortality. While lower early life SEP was associated with reduced breast cancer incidence and increased breast cancer mortality in the US, studies conducted in Europe were unable to establish a consistent association.We found moderate support for the association between early life SEP and incidence and mortality from breast cancer. The impact of early life SEP on breast cancer incidence and mortality appeared to vary between countries. We urge further investigation of the role of lifelong SEP trajectories in breast cancer outcomes.
View details for DOI 10.1007/s00038-017-1060-8
View details for Web of Science ID 000444585200003
View details for PubMedID 29197969
View details for PubMedCentralID PMC5984656
How and why studies disagree about the effects of education on health: A systematic review and meta-analysis of studies of compulsory schooling laws
SOCIAL SCIENCE & MEDICINE
2018; 212: 168–78
Rich literatures across multiple disciplines document the association between increased educational attainment and improved health. While quasi-experimental studies have exploited variation in educational policies to more rigorously estimate the health effects of education, there remains disagreement about whether education and health are causally linked. The aim of this study was to conduct a systematic review and meta-analysis to characterize this literature, with a focus on quasi-experimental studies of compulsory schooling laws (CSLs). Articles from 1990 to 2015 were obtained through electronic searches and manual searches of reference lists. We searched for English-language studies and included manuscripts if: (1) they involved original data analysis; (2) outcomes were health-related; and (3) the primary predictor utilized variation in CSLs. We identified 89 articles in 25 countries examining over 25 health outcomes, with over 600 individual point estimates. We systematically characterized heterogeneity on key study design features and conducted a meta-analysis of studies with comparable health outcome and exposure variables. Within countries, studies differed in terms of birth cohorts included, the measurement of health outcomes within a given category, and the type of CSL variation examined. Over 90% of manuscripts included multiple analytic techniques, such as econometric and standard regression methods, with as many as 31 "primary" models in a single study. A qualitative synthesis of study findings indicated that educational attainment has an effect on the majority of health outcomes-most beneficial, some negative-while the meta-analysis demonstrated small beneficial effects for mortality, smoking, and obesity. Future work could focus on inconsistent findings identified by this study, or review the health effects of other types of educational policies.
View details for DOI 10.1016/j.socscimed.2018.07.016
View details for Web of Science ID 000442056900019
View details for PubMedID 30036767
Associations between cumulative neighborhood deprivation, long-term mobility trajectories, and gestational weight gain
HEALTH & PLACE
2018; 52: 101–9
Existing research on neighborhood environment and gestational weight gain (GWG) focuses on point-in-time measures of neighborhood context. This precludes understanding how long-term exposure to adverse neighborhood environments influences GWG. We estimated associations between average exposure to and trajectories of long-term neighborhood socioeconomic deprivation and risk of inadequate or excessive GWG. Using data from 5690 full-term, singleton pregnancies in the 1979 National Longitudinal Survey of Youth, we estimated associations between cumulative deprivation and GWG, overall and by race/ethnicity, controlling for individual and residential covariates. A one standard deviation unit (8-point) increase in neighborhood deprivation increased risk of inadequate GWG (Relative Risk (RR): 1.08; 95% Confidence Interval (CI): 1.00-1.16) for all women and excessive GWG (RR: 1.11; 95% CI 1.02-1.21) for white women. Persistent low deprivation (RR: 0.78; 95% CI: 0.64-0.94) and upward mobility (RR: 0.76; 95% CI: 0.61-0.96), compared to persistent high deprivation, reduced risk of inadequate GWG. Persistent low deprivation also reduced risk of excessive GWG (RR: 0.84; 95% CI: 0.71-0.98). Long-term neighborhood deprivation contributes to patterns of GWG over women's life course.
View details for DOI 10.1016/j.healthplace.2018.05.007
View details for Web of Science ID 000439053800011
View details for PubMedID 29883957
Poverty dynamics, poverty thresholds and mortality: An age-stage Markovian model
2018; 13 (5): e0195734
Recent studies have examined the risk of poverty throughout the life course, but few have considered how transitioning in and out of poverty shape the dynamic heterogeneity and mortality disparities of a cohort at each age. Here we use state-by-age modeling to capture individual heterogeneity in crossing one of three different poverty thresholds (defined as 1×, 2× or 3× the "official" poverty threshold) at each age. We examine age-specific state structure, the remaining life expectancy, its variance, and cohort simulations for those above and below each threshold. Survival and transitioning probabilities are statistically estimated by regression analyses of data from the Health and Retirement Survey RAND data-set, and the National Longitudinal Survey of Youth. Using the results of these regression analyses, we parameterize discrete state, discrete age matrix models. We found that individuals above all three thresholds have higher annual survival than those in poverty, especially for mid-ages to about age 80. The advantage is greatest when we classify individuals based on 1× the "official" poverty threshold. The greatest discrepancy in average remaining life expectancy and its variance between those above and in poverty occurs at mid-ages for all three thresholds. And fewer individuals are in poverty between ages 40-60 for all three thresholds. Our findings are consistent with results based on other data sets, but also suggest that dynamic heterogeneity in poverty and the transience of the poverty state is associated with income-related mortality disparities (less transience, especially of those above poverty, more disparities). This paper applies the approach of age-by-stage matrix models to human demography and individual poverty dynamics. In so doing we extend the literature on individual poverty dynamics across the life course.
View details for DOI 10.1371/journal.pone.0195734
View details for Web of Science ID 000432329200009
View details for PubMedID 29768416
View details for PubMedCentralID PMC5955488
Geographic Clustering of Polygenic Scores at Different Stages of the Life Course.
The Russell Sage Foundation journal of the social sciences : RSF
2018; 4 (4): 137–49
We interrogate state-level clustering of polygenic scores at different points in the life course and variation in the association of mean polygenic scores in a respondent's state of birth with corresponding phenotypes. The polygenic scores for height and smoking show the most state-level clustering (2 to 4 percent) with relatively little clustering observed for the other scores. However, even the small amounts of observed clustering are potentially meaningful. The state-mean polygenic score for educational attainment is strongly associated with an individual's educational attainment net of that person's polygenic score. The ecological clustering of polygenic scores may denote a new environmental factor in gene-environment research. We conclude by discussing possible mechanisms that underlie this association and the implications of our findings for social and genetic research.
View details for DOI 10.7758/rsf.2018.4.4.08
View details for PubMedID 30740524
Machine learning approaches to the social determinants of health in the health and retirement study
2018; 4: 95–99
Social and economic factors are important predictors of health and of recognized importance for health systems. However, machine learning, used elsewhere in the biomedical literature, has not been extensively applied to study relationships between society and health. We investigate how machine learning may add to our understanding of social determinants of health using data from the Health and Retirement Study.A linear regression of age and gender, and a parsimonious theory-based regression additionally incorporating income, wealth, and education, were used to predict systolic blood pressure, body mass index, waist circumference, and telomere length. Prediction, fit, and interpretability were compared across four machine learning methods: linear regression, penalized regressions, random forests, and neural networks.All models had poor out-of-sample prediction. Most machine learning models performed similarly to the simpler models. However, neural networks greatly outperformed the three other methods. Neural networks also had good fit to the data (R 2 between 0.4-0.6, versus <0.3 for all others). Across machine learning models, nine variables were frequently selected or highly weighted as predictors: dental visits, current smoking, self-rated health, serial-seven subtractions, probability of receiving an inheritance, probability of leaving an inheritance of at least $10,000, number of children ever born, African-American race, and gender.Some of the machine learning methods do not improve prediction or fit beyond simpler models, however, neural networks performed well. The predictors identified across models suggest underlying social factors that are important predictors of biological indicators of chronic disease, and that the non-linear and interactive relationships between variables fundamental to the neural network approach may be important to consider.
View details for DOI 10.1016/j.ssmph.2017.11.008
View details for Web of Science ID 000440723000012
View details for PubMedID 29349278
View details for PubMedCentralID PMC5769116
AMultiple-Imputation "Forward Bridging" Approach to Address Changes in the Classification of Asian Race/Ethnicity on the US Death Certificate
AMERICAN JOURNAL OF EPIDEMIOLOGY
2018; 187 (2): 347–57
The incomparability of old and new classification systems for describing the same data can be seen as a missing-data problem, and, under certain assumptions, multiple imputation may be used to "bridge" 2 classification systems. One example of such a change is the introduction of detailed Asian-American race/ethnicity classifications on the 2003 version of the US national death certificate, which was adopted for use by 38 states between 2003 and 2011. Using county- and decedent-level data from 3 different national sources for pre- and postadoption years, we fitted within-state multiple-imputation models to impute ethnicities for decedents classified as "other Asian" during preadoption years. We present mortality rates derived using 3 different methods of calculation: 1) including all states but ignoring the gradual adoption of the new death certificate over time, 2) including only the 7 states with complete reporting of all ethnicities, and 3) including all states and applying multiple imputation. Estimates from our imputation model were consistently in the middle of the other 2 estimates, and trend results demonstrated that the year-by-year estimates of the imputation model were more similar to those of the 7-state model. This work demonstrates how multiple imputation can provide a "forward bridging" approach to make more accurate estimates over time in newly categorized populations.
View details for DOI 10.1093/aje/kwx215
View details for Web of Science ID 000423821100019
View details for PubMedID 29401361
View details for PubMedCentralID PMC5860289
Association Between Cardiorespiratory Fitness and Health Care Costs: The Veterans Exercise Testing Study
MAYO CLINIC PROCEEDINGS
2018; 93 (1): 48–55
To determine the association between cardiorespiratory fitness (CRF) and annual health care costs in Veterans.The sample included 9942 subjects (mean age, 59±11 years) undergoing a maximal exercise test for clinical reasons between January 2005 and December 2012. Cardiorespiratory fitness, expressed as a percentage of age-predicted peak metabolic equivalents (METs) achieved, was categorized in quartiles. Total and annualized health care costs, derived from the Veterans Administration Allocated Resource Center, were compared using multiple regression, controlling for demographic and clinical characteristics.A gradient for reduced health care costs was observed as CRF increased, with subjects in the least-fit quartile having approximately $14,662 (P<.001) higher overall costs per patient per year compared with those in the fittest quartile, after controlling for potential confounding variables. Each 1-MET higher increment in fitness was associated with a $1592 annual reduction in health care costs (5.6% lower cost per MET), and each higher quartile of fitness was associated with a $4163 annual cost reduction per patient. The effect of CRF was more pronounced among subjects without cardiovascular disease (CVD), suggesting that the results were not driven by the possibility that less-fit individuals had greater CVD. Cost savings attributable to higher fitness were greatest in overweight and obese subjects, with lower savings observed among those individuals with a body mass index less than 25 kg/m2. In a model including historical, clinical, and exercise test responses, heart failure was the strongest predictor of health care costs, followed by CRF (P<.01).Low CRF is associated with higher health care costs. Efforts to improve CRF may not only improve health but also result in lower health care costs.
View details for DOI 10.1016/j.mayocp.2017.09.019
View details for Web of Science ID 000419089800012
View details for PubMedID 29195922
Motherhood, fatherhood and midlife weight gain in a US cohort: Associations differ by race/ethnicity and socioeconomic position
2017; 3: 558–65
While there is an association of greater short-term weight gain with childbearing among women, less is known about longer-term weight gain, whether men have similar gains, and how this varies by race/ethnicity and socioeconomic position. Our cohort consisted of a nationally representative sample of 7,356 Americans with oversampling of Black and Hispanic populations. We estimated the associations between number of biological children and parental weight, measured as both change in self-reported body mass index (BMI) from age 18 and overweight/obese status (BMI ≥ 25) at age 40. We performed multivariate linear and logistic regression analysis and tested for effect modification by gender. For change in BMI, men gained on average 0.28 BMI (95% CI: (0.01, 0.55)) units per child, while women gained 0.13 units per child (95% CI: (-0.22, 0.48)). The adjusted odds ratios for overweight/obesity associated with each child were 1.32 (95% CI: (1.11, 1.58)) for men and 1.15 (95% CI: (1.01, 1.31)) for women. Stratified analyses by race/ethnicity and socioeconomic position suggested that the observed full-cohort differences were driven primarily by gendered differences in low-income Hispanics and Whites - with the greatest associations among Hispanic men. For example, among low-income Hispanic men we observed a positive relationship between the number of children and weight change by age 40, with average weight change of 0.47 units per child (95%CI: (-0.65, 1.59 For low-income Hispanic women, however, the average weight change was -0.59 units per child (95%CI: (-1.70, 0.47), and the P-value for the test of interaction between gender and number of children was P < 0.001. Our findings suggest that the shared social and economic aspects of raising children play an important role in determining parental weight at mid-life.
View details for DOI 10.1016/j.ssmph.2017.06.004
View details for Web of Science ID 000448680700062
View details for PubMedID 29204513
View details for PubMedCentralID PMC5711467
- The need to monitor actions on the social determinants of health BULLETIN OF THE WORLD HEALTH ORGANIZATION 2017; 95 (11): 784–87
Excessive Gestational Weight Gain and Subsequent Maternal Obesity at Age 40: A Hypothetical Intervention
AMERICAN JOURNAL OF PUBLIC HEALTH
2017; 107 (9): 1463–69
To model the hypothetical impact of preventing excessive gestational weight gain on midlife obesity and compare the estimated reduction with the US Healthy People 2020 goal of a 10% reduction of obesity prevalence in adults.We analyzed 3917 women with 1 to 3 pregnancies in the prospective US National Longitudinal Survey of Youth, from 1979 to 2012. We compared the estimated obesity prevalence between 2 scenarios: gestational weight gain as reported and under the scenario of a hypothetical intervention that all women with excessive gestational weight gain instead gained as recommended by the Institute of Medicine (2009).A hypothetical intervention was associated with a significantly reduced estimated prevalence of obesity for first (3.3 percentage points; 95% confidence interval [CI] = 1.0, 5.6) and second (3.0 percentage points; 95% CI = 0.7, 5.2) births, and twice as high in Black as in White mothers, but not significant in Hispanics. The population attributable fraction was 10.7% (95% CI = 3.3%, 18.1%) in first and 9.3% (95% CI = 2.2%, 16.5%) in second births.Development of effective weight-management interventions for childbearing women could lead to meaningful reductions in long-term obesity.
View details for DOI 10.2105/AJPH.2017.303881
View details for Web of Science ID 000412491700044
View details for PubMedID 28727522
View details for PubMedCentralID PMC5551596
Geographic Variations in Cardiovascular Disease Mortality Among Asian American Subgroups, 2003-2011
JOURNAL OF THE AMERICAN HEART ASSOCIATION
2017; 6 (7)
There are well-documented geographical differences in cardiovascular disease (CVD) mortality for non-Hispanic whites. However, it remains unknown whether similar geographical variation in CVD mortality exists for Asian American subgroups. This study aims to examine geographical differences in CVD mortality among Asian American subgroups living in the United States and whether they are consistent with geographical differences observed among non-Hispanic whites.Using US death records from 2003 to 2011 (n=3 897 040 CVD deaths), age-adjusted CVD mortality rates per 100 000 population and age-adjusted mortality rate ratios were calculated for the 6 largest Asian American subgroups (Asian Indian, Chinese, Filipino, Japanese, Korean, and Vietnamese) and compared with non-Hispanic whites. There were consistently lower mortality rates for all Asian American subgroups compared with non-Hispanic whites across divisions for CVD mortality and ischemic heart disease mortality. However, cerebrovascular disease mortality demonstrated substantial geographical differences by Asian American subgroup. There were a number of regional divisions where certain Asian American subgroups (Filipino and Japanese men, Korean and Vietnamese men and women) possessed no mortality advantage compared with non-Hispanic whites. The most striking geographical variation was with Filipino men (age-adjusted mortality rate ratio=1.18; 95% CI, 1.14-1.24) and Japanese men (age-adjusted mortality rate ratio=1.05; 95% CI: 1.00-1.11) in the Pacific division who had significantly higher cerebrovascular mortality than non-Hispanic whites.There was substantial geographical variation in Asian American subgroup mortality for cerebrovascular disease when compared with non-Hispanic whites. It deserves increased attention to prioritize prevention and treatment in the Pacific division where approximately 80% of Filipinos CVD deaths and 90% of Japanese CVD deaths occur in the United States.
View details for DOI 10.1161/JAHA.117.005597
View details for Web of Science ID 000406278900036
View details for PubMedID 28701306
View details for PubMedCentralID PMC5586288
Maternal History of Child Abuse and Obesity Risk in Offspring: Mediation by Weight in Pregnancy.
Women's experience of childhood adversity may contribute to their children's risk of obesity. Possible causal pathways include higher maternal weight and gestational weight gain, which have been associated with both maternal childhood adversity and obesity in offspring.This study included 6718 mother-child pairs from the National Longitudinal Survey of Youth 1979 in the United States (1979-2012). We applied multiple log-binomial regression models to estimate associations between three markers of childhood adversity (physical abuse, household alcoholism, and household mental illness) and offspring obesity in childhood. We estimated natural direct effects to evaluate mediation by prepregnancy BMI and gestational weight gain.Among every 100 mothers who reported physical abuse in childhood, there were 3.7 (95% confidence interval: -0.1 to 7.5) excess cases of obesity in 2- to 5-year olds compared with mothers who did not report physical abuse. Differences in prepregnancy BMI, but not gestational weight gain, accounted for 25.7% of these excess cases. There was no evidence of a similar relationship for household alcoholism or mental illness or for obesity in older children.In this national, prospective cohort study, prepregnancy BMI partially explained an association between maternal physical abuse in childhood and obesity in preschool-age children. These findings underscore the importance of life-course exposures in the etiology of child obesity and the potential multi-generational consequences of child abuse. Research is needed to determine whether screening for childhood abuse and treatment of its sequelae could strengthen efforts to prevent obesity in mothers and their children.
View details for DOI 10.1089/chi.2017.0019
View details for PubMedID 28440693
Prevalence of Chronic Disease and Their Risk Factors Among Iranian, Ukrainian, Vietnamese Refugees in California, 2002-2011.
Journal of immigrant and minority health
2016; 18 (6): 1274-1283
Little is known about how the health status of incoming refugees to the United States compares to that of the general population. We used logistic regression to assess whether country of origin is associated with prevalence of hypertension, obesity, type-II diabetes, and tobacco-use among Iranian, Ukrainian and Vietnamese refugees arriving in California from 2002 to 2011 (N = 21,968). We then compared the prevalence among refugees to that of the Californian general population (CGP). Ukrainian origin was positively associated with obesity and negatively with smoking, while the opposite was true for Vietnamese (p < 0.001). Iranian origin was positively associated with type-II diabetes and smoking (p < 0.001). After accounting for age and gender differences, refugees had lower prevalence of obesity and higher prevalence of smoking than CGP. Individually, all refugee groups had lower type-II diabetes prevalence than CGP. Grouping all refugees together can hide distinct health needs associated with country of origin.
View details for PubMedID 26691740
Predicting later life health status and mortality using state-level socioeconomic characteristics in early life.
SSM - population health
2016; 2: 269-276
Studies extending across multiple life stages promote an understanding of factors influencing health across the life span. Existing work has largely focused on individual-level rather than area-level early life determinants of health. In this study, we linked multiple data sets to examine whether early life state-level characteristics were predictive of health and mortality decades later. The sample included 143,755 U.S. employees, for whom work life claims and administrative data were linked with early life state-of-residence and mortality. We first created a "state health risk score" (SHRS) and "state mortality risk score" (SMRS) by modeling state-level contextual characteristics with health status and mortality in a randomly selected 30% of the sample (the "training set"). We then examined the association of these scores with objective health status and mortality in later life in the remaining 70% of the sample (the "test set") using multivariate linear and Cox regressions, respectively. The association between the SHRS and adult health status was β=0.14 (95%CI: 0.084, 0.20), while the hazard ratio for the SMRS was 0.96 (95%CI: 0.93, 1.00). The association between the SHRS and health was not statistically significant in older age groups at a p-level of 0.05, and there was a statistically significantly different association for health status among movers compared to stayers. This study uses a life course perspective and supports the idea of "sensitive periods" in early life that have enduring impacts on health. It adds to the literature examining populations in the U.S. where large linked data sets are infrequently available.
View details for PubMedID 27713921
View details for PubMedCentralID PMC5047283
Changing national guidelines is not enough: the impact of 1990 IOM recommendations on gestational weight gain among US women.
International journal of obesity
2016; 40 (10): 1529-1534
Gestational weight gain (GWG) is associated with both long- and short-term maternal and child health outcomes, particularly obesity. Targeting maternal nutrition through policies is a potentially powerful pathway to influence these outcomes. Yet prior research has often failed to evaluate national policies and guidelines that address maternal and child health. In 1990, the U.S. Institute of Medicine (IOM) released guidelines recommending different GWG thresholds based on women's pre-pregnancy body mass index (BMI), with the goal of improving infant birth weight. In this study, we employ quasi-experimental methods to examine whether the release of the IOM guidelines led to changes in GWG among a diverse and nationally representative sample of women.Our sample included female participants of the National Longitudinal Survey of Youth who self-reported GWG for pregnancies during 1979-2000 (n=7442 pregnancies to 4173 women). We compared GWG before and after the guidelines were released using difference-in-differences (DID) and regression discontinuity (RD) analyses.In DID analyses we found no reduction in GWG among overweight/obese women relative to normal/underweight women. Meanwhile, RD analyses demonstrated no changes in GWG by pre-pregnancy BMI for either overweight/obese or normal/underweight women. Results were similar for women regardless of educational attainment, race or parity.These findings suggest that national guidelines had no effect on weight gain among pregnant women. These results have implications for the implementation of policies targeting maternal and child health via dietary behaviors.
View details for DOI 10.1038/ijo.2016.97
View details for PubMedID 27200502
View details for PubMedCentralID PMC5050079
Telomere length and health outcomes: A two-sample genetic instrumental variables analysis.
2016; 82: 88-94
Previous studies linking telomere length (TL) and health have been largely associational. We apply genetic instrumental variables (IV) analysis, also known as Mendelian randomization, to test the hypothesis that shorter TL leads to poorer health. This method reduces bias from reverse causation or confounding.We used two approaches in this study that rely on two separate data sources: (1) individual-level data from the Health and Retirement Study (HRS) (N=3734), and (2) coefficients from genome-wide association studies (GWAS). We employed two-sample genetic IV analyses, constructing a polygenic risk score (PRS) of TL-associated single nucleotide polymorphisms. The first approach examined the association of the PRS with nine individual health outcomes in HRS. The second approach took advantage of estimates available in GWAS databases to estimate the impact of TL on five health outcomes using an inverse variance-weighted meta-analytic technique.Using individual-level data, shorter TL was marginally statistically significantly associated with decreased risk of stroke and increased risk of heart disease. Using the meta-analytic approach, shorter TL was associated with increased risk of coronary artery disease (OR 1.02 per 100 base pairs, 95%CI: 1.00, 1.03).With the exception of a small contribution to heart disease, our findings suggest that TL may be a marker of disease rather than a cause. They also demonstrate the utility of the inverse variance-weighted meta-analytic approach when examining small effect sizes.
View details for DOI 10.1016/j.exger.2016.06.005
View details for PubMedID 27321645
View details for PubMedCentralID PMC4969151
Racial and Socioeconomic Variation in Genetic Markers of Telomere Length: A Cross-Sectional Study of U.S. Older Adults.
2016; 11: 296-301
Shorter telomere length (TL) has been associated with stress and adverse socioeconomic conditions, yet U.S. blacks have longer TL than whites. The role of genetic versus environmental factors in explaining TL by race and socioeconomic position (SEP) remains unclear.We used data from the U.S. Health and Retirement Study (N=11,934) to test the hypothesis that there are differences in TL-associated SNPs by race and SEP. We constructed a TL polygenic risk score (PRS) and examined its association with race/ethnicity, educational attainment, assets, gender, and age.U.S. blacks were more likely to have a lower PRS for TL, as were older individuals and men. Racial differences in TL were statistically accounted for when controlling for population structure using genetic principal components. The GWAS-derived SNPs for TL, however, may not have consistent associations with TL across different racial/ethnic groups.This study showed that associations of race/ethnicity with TL differed when accounting for population stratification. The role of race/ethnicity for TL remains uncertain, however, as the genetic determinants of TL may differ by race/ethnicity. Future GWAS samples should include racially diverse participants to allow for better characterization of the determinants of TL in human populations.
View details for DOI 10.1016/j.ebiom.2016.08.015
View details for PubMedID 27566956
View details for PubMedCentralID PMC5049995
- Reply to Yang et al.: GCTA produces unreliable heritability estimates. Proceedings of the National Academy of Sciences of the United States of America 2016; 113 (32): E4581-?
Educational Attainment and Gestational Weight Gain among US Mothers
WOMENS HEALTH ISSUES
2016; 26 (4): 460-467
Education is an important social determinant of many health outcomes, but the relationship between educational attainment and the amount of weight gained over the course of a woman's pregnancy (gestational weight gain [GWG]) has not been established clearly.We used data from 1979 through 2010 for women in the National Longitudinal Survey of Youth (1979) cohort (n = 6,344 pregnancies from 2,769 women). We used generalized estimating equations to estimate the association between educational attainment and GWG adequacy (as defined by 2009 Institute of Medicine guidelines), controlling for diverse social factors from across the life course (e.g., income, wealth, educational aspirations and expectations) and considering effect measure modification by race/ethnicity and prepregnancy overweight status.In most cases, women with more education had increased odds of gaining a recommended amount of gestational weight, independent of educational aspirations and educational expectations and relatively robust to sensitivity analyses. This trend manifested itself in a few different ways. Those with less education had higher odds of inadequate GWG than those with more education. Among those who were not overweight before pregnancy, those with less education had higher odds of excessive GWG than college graduates. Among women who were White, those with less than a high school degree had higher odds of excessive GWG than those with more education.The relationship between educational attainment and GWG is nuanced and nonlinear.
View details for DOI 10.1016/j.whi.2016.05.009
View details for Web of Science ID 000380748900014
View details for PubMedID 27372419
Adverse childhood experiences and later life adult obesity and smoking in the United States.
Annals of epidemiology
2016; 26 (7): 488-492 e5
Prior work demonstrates associations between physical abuse, household alcohol abuse, and household mental illness early in life with obesity and smoking. Studies, however, have not generally been in nationally representative samples and have not conducted analyses to account for bias in the exposure.We used data from the 1979 U.S. National Longitudinal Survey of Youth to test associations between measures of adverse childhood experiences with obesity and smoking and used an instrumental variables approach to address potential measurement error of the exposure.Models demonstrated associations between childhood physical abuse and obesity at age 40 years (odds ratio [OR] 1.23; 95% confidence interval [CI], 1.00-1.52) and ever smoking (OR 1.83; 95% CI, 1.56-2.16), as well as associations between household alcohol abuse (OR 1.53; 95% CI, 1.31-1.79) and household mental illness (OR 1.29; 95% CI, 1.04-1.60) with ever smoking. We find no evidence of association modification by gender, socioeconomic position, or race and/or ethnicity. Instrumental variables analysis using a sibling's report of adverse childhood experiences demonstrated a relationship between household alcohol abuse and smoking, with a population attributable fraction of 17% (95% CI, 2.0%-37%) for ever smoking and 6.7% (95% CI, 1.6%-12%) for currently smoking.Findings suggest long-term impacts of childhood exposure to physical abuse, household alcohol abuse, and parental mental illness on obesity and smoking and that the association between household alcohol abuse and smoking is not solely due to measurement error.
View details for DOI 10.1016/j.annepidem.2016.06.003
View details for PubMedID 27449570
- Adverse childhood experiences and later life adult obesity and smoking in the United States ANNALS OF EPIDEMIOLOGY 2016; 26 (7): 488-492
Weight gain in pregnancy and child weight status from birth to adulthood in the United States.
High weight gain in pregnancy has been associated with child adiposity, but few studies have assessed the relationship across childhood or in racially/ethnically diverse populations.The objectives of the study are to test if weight gain in pregnancy is associated with high birthweight and overweight/obesity in early, middle and late childhood and whether these associations differ by maternal race/ethnicity.Mother-child dyads (n = 7539) were included from the National Longitudinal Survey of Youth 1979, a nationally representative cohort study in the USA (1979-2012). Log-binomial regression models were used to analyse associations between weight gain and the outcomes: high birthweight (>4000 g) and overweight/obesity at ages 2-5, 6-11 and 12-19 years.Excessive weight gain was positively associated, and inadequate weight gain was negatively associated with high birthweight after confounder adjustment (P < 0.05). Only excessive weight gain was associated with overweight in early, middle and late childhood. These associations were not significant in Hispanics or Blacks although racial/ethnic interaction was only significant ages 12-19 years (P = 0.03).Helping pregnant women gain weight within national recommendations may aid in preventing overweight and obesity across childhood, particularly for non-Hispanic White mothers.
View details for DOI 10.1111/ijpo.12163
View details for PubMedID 27350375
View details for PubMedCentralID PMC5404997
Poverty and Child Development: A Longitudinal Study of the Impact of the Earned Income Tax Credit
AMERICAN JOURNAL OF EPIDEMIOLOGY
2016; 183 (9): 775-784
Although adverse socioeconomic conditions are correlated with worse child health and development, the effects of poverty-alleviation policies are less understood. We examined the associations of the Earned Income Tax Credit (EITC) on child development and used an instrumental variable approach to estimate the potential impacts of income. We used data from the US National Longitudinal Survey of Youth (n = 8,186) during 1986-2000 to examine effects on the Behavioral Problems Index (BPI) and Home Observation Measurement of the Environment inventory (HOME) scores. We conducted 2 analyses. In the first, we used multivariate linear regressions with child-level fixed effects to examine the association of EITC payment size with BPI and HOME scores; in the second, we used EITC payment size as an instrument to estimate the associations of income with BPI and HOME scores. In linear regression models, higher EITC payments were associated with improved short-term BPI scores (per $1,000, β = -0.57; P = 0.04). In instrumental variable analyses, higher income was associated with improved short-term BPI scores (per $1,000, β = -0.47; P = 0.01) and medium-term HOME scores (per $1,000, β = 0.64; P = 0.02). Our results suggest that both EITC benefits and higher income are associated with modest but meaningful improvements in child development. These findings provide valuable information for health researchers and policymakers for improving child health and development.
View details for DOI 10.1093/aje/kwv317
View details for Web of Science ID 000376097600001
View details for PubMedID 27056961
View details for PubMedCentralID PMC4851995
Predicting Survival from Telomere Length versus Conventional Predictors: A Multinational Population-Based Cohort Study
2016; 11 (4)
Telomere length has generated substantial interest as a potential predictor of aging-related diseases and mortality. Some studies have reported significant associations, but few have tested its ability to discriminate between decedents and survivors compared with a broad range of well-established predictors that include both biomarkers and commonly collected self-reported data. Our aim here was to quantify the prognostic value of leukocyte telomere length relative to age, sex, and 19 other variables for predicting five-year mortality among older persons in three countries. We used data from nationally representative surveys in Costa Rica (N = 923, aged 61+), Taiwan (N = 976, aged 54+), and the U.S. (N = 2672, aged 60+). Our study used a prospective cohort design with all-cause mortality during five years post-exam as the outcome. We fit Cox hazards models separately by country, and assessed the discriminatory ability of each predictor. Age was, by far, the single best predictor of all-cause mortality, whereas leukocyte telomere length was only somewhat better than random chance in terms of discriminating between decedents and survivors. After adjustment for age and sex, telomere length ranked between 15th and 17th (out of 20), and its incremental contribution was small; nine self-reported variables (e.g., mobility, global self-assessed health status, limitations with activities of daily living, smoking status), a cognitive assessment, and three biological markers (C-reactive protein, serum creatinine, and glycosylated hemoglobin) were more powerful predictors of mortality in all three countries. Results were similar for cause-specific models (i.e., mortality from cardiovascular disease, cancer, and all other causes combined). Leukocyte telomere length had a statistically discernible, but weak, association with mortality, but it did not predict survival as well as age or many other self-reported variables. Although telomere length may eventually help scientists understand aging, more powerful and more easily obtained tools are available for predicting survival.
View details for DOI 10.1371/journal.pone.0152486
View details for Web of Science ID 000373603500043
View details for PubMedID 27049651
Maternal Childhood Adversity, Prepregnancy Obesity, and Gestational Weight Gain.
American journal of preventive medicine
2016; 50 (4): 463-469
Growing evidence suggests that exposure to childhood adversity may influence obesity across the life course. High maternal weight complicates pregnancy and increases the risk of child obesity. This study examined the association between maternal childhood adversity and pregnancy-related weight in a large U.S.Data on 6,199 pregnancies from 2,873 women followed from 1979 to 2012 by the National Longitudinal Survey of Youth 1979 were analyzed in 2014. Associations between three adversity exposures before age 18 years (history of physical abuse, alcohol problems, or mental illness in the household) and two maternal weight outcomes (prepregnancy obesity and excessive gestational weight gain) were modeled separately using survey-adjusted log-binomial models.After adjusting for race/ethnicity and early-life socioeconomic factors, childhood physical abuse was associated with a 60% increase in the risk of prepregnancy obesity (adjusted risk ratio=1.6, 95% CI=1.1, 2.2). Household alcohol abuse was associated with a 30% increase in prepregnancy obesity (adjusted risk ratio=1.3, 95% CI=1.0, 1.7), as was household mental illness (adjusted risk ratio=1.3, 95% CI=0.8, 1.9), but the mental illness exposure was not significant. Physical abuse and household alcohol abuse were associated with a significant 20% increase in the risk of excessive gestational weight gain; mental illness was not.Adversity in early life may affect maternal weight before and during pregnancy. Screening and treating women of reproductive age for childhood adversity and its negative effects could significantly reduce obesity-related health outcomes for women and their children.
View details for DOI 10.1016/j.amepre.2015.08.032
View details for PubMedID 26558699
Heterogeneous Effects of Housing Vouchers on the Mental Health of US Adolescents.
American journal of public health
2016; 106 (4): 755-762
To assess the mental health effects on adolescents of low-income families residing in high-poverty public housing who received housing vouchers to assist relocation.We defined treatment effects to compare 2829 adolescents aged 12 to 19 years in families offered housing vouchers versus those living in public housing in the Moving to Opportunity experiment (1994-1997; Boston, MA; Baltimore, MD; Chicago, IL; Los Angeles, CA; New York, NY). We employed model-based recursive partitioning to identify subgroups with heterogeneous treatment effects on psychological distress and behavior problems measured in 2002. We tested 35 potential baseline treatment modifiers.For psychological distress, Chicago participants experienced null treatment effects. Outside Chicago, boys experienced detrimental effects, whereas girls experienced beneficial effects. Behavior problems effects were null for adolescents who were aged 10 years or younger at baseline. For adolescents who were older than 10 years at baseline, violent crime victimization, unmarried parents, and unsafe neighborhoods increased adverse treatment effects. Adolescents who were older than 10 years at baseline without learning problems or violent crime victimization, and whose parents moved for better schools, experienced beneficial effects.Health effects of housing vouchers varied across subgroups. Supplemental services may be necessary for vulnerable subgroups for whom housing vouchers alone may not be beneficial.
View details for DOI 10.2105/AJPH.2015.303006
View details for PubMedID 26794179
View details for PubMedCentralID PMC4986050
- Health Behaviors, Mental Health, and Health Care Utilization Among Single Mothers After Welfare Reforms in the 1990s AMERICAN JOURNAL OF EPIDEMIOLOGY 2016; 183 (6): 531-538
- Basu et al. Respond to "Interdisciplinary Approach for Policy Evaluation". American journal of epidemiology 2016; 183 (6): 542-543
Health Behaviors, Mental Health, and Health Care Utilization Among Single Mothers After Welfare Reforms in the 1990s.
American journal of epidemiology
2016; 183 (6): 531-538
We studied the health of low-income US women affected by the largest social policy change in recent US history: the 1996 welfare reforms. Using the Behavioral Risk Factor Surveillance System (1993-2012), we performed 2 types of analysis. First, we used difference-in-difference-in-differences analyses to estimate associations between welfare reforms and health outcomes among the most affected women (single mothers aged 18-64 years in 1997; n = 219,469) compared with less affected women (married mothers, single nonmothers, and married nonmothers of the same age range in 1997; n = 2,422,265). We also used a synthetic control approach in which we constructed a more ideal control group for single mothers by weighting outcomes among the less affected groups to match pre-reform outcomes among single mothers. In both specifications, the group most affected by welfare reforms (single mothers) experienced worse health outcomes than comparison groups less affected by the reforms. For example, the reforms were associated with at least a 4.0-percentage-point increase in binge drinking (95% confidence interval: 0.9, 7.0) and a 2.4-percentage-point decrease in the probability of being able to afford medical care (95% confidence interval: 0.1, 4.8) after controlling for age, educational level, and health care insurance status. Although the reforms were applauded for reducing welfare dependency, they may have adversely affected health.
View details for DOI 10.1093/aje/kwv249
View details for PubMedID 26946395
The Consistency Assumption for Causal Inference in Social Epidemiology: When a Rose is Not a Rose.
Current epidemiology reports
2016; 3 (1): 63-71
The assumption that exposures as measured in observational settings have clear and specific definitions underpins epidemiologic research and allows us to use observational data to predict outcomes in interventions. This leap between exposures as measured and exposures as intervened upon is typically supported by the consistency assumption. The consistency assumption has received extensive attention in risk factor epidemiology but relatively little emphasis in social epidemiology. However, violations of the consistency assumption may be especially important to consider when understanding how social and economic exposures influence health. Efforts to clarify the definitions of our exposures, thus bolstering the consistency assumption, will help guide interventions to improve population health and reduce health disparities. This article focuses on the consistency assumption as considered within social epidemiology. We explain how this assumption is articulated in the causal inference literature and give examples of how it might be violated for three common exposure in social epidemiology research: income, education and neighborhood characteristics. We conclude that there is good reason to worry about consistency assumption violations in much of social epidemiology research. Theoretically motivated explorations of mechanisms along with empirical comparisons of research findings under alternative operationalizations of exposure can help identify consistency violations. We recommend that future social epidemiology studies be more explicit to name and discuss the consistency assumption when describing the exposure of interest, including reconciling disparate results in the literature.
View details for PubMedID 27326386
Trends in Socioeconomic Inequalities in Body Mass Index, Underweight and Obesity among English Children, 2007-2008 to 2011-2012
2016; 11 (1)
Socioeconomic inequalities in childhood obesity have been reported in most developed countries, with obesity more common in deprived groups. Whether inequalities are found in the prevalence of underweight, the rest of the body mass index (BMI) distribution, or have changed across time is not clear.The sample comprised 5,027,128 children on entry (4 to 5 years old) and leaving (10 to 11 years) state primary (elementary) school who participated in the National Child Measurement Programme (England, United Kingdom). We used area-level deprivation (Indices of Multiple Deprivation at the lower super output area) as a measure of socioeconomic deprivation. From 2007-2008 to 2011-2012 inequalities in obesity between the most compared to least deprived group increased (from 7.21% to 8.30%; p<0.001), whereas inequalities in the prevalence of underweight (1.50% to 1.21%; p = 0.15) were stable during this period. There were no differences by age group or by sex, but a three-way interaction suggested inequalities in obesity had increased at a faster rate for 10 to 11 year old girls, than 4 to 5 year old boys, (2.03% vs 0.07%; p<0.001 for interaction). Investigating inequalities across the distribution of zBMI showed increases in mean zBMI (0.18 to 0.23, p<0.001) could be attributed to increases in inequalities between the 50th and 75th centiles of BMI. Using the 2011 to 2012 population attributable risk estimates, if inequalities were halved, 14.04% (95% CI 14.00% to 14.07%) of childhood obesity could be avoided.Socioeconomic inequalities in childhood obesity and zBMI increased in England between 2007-2008 and 2011-2012. Inequalities in the prevalence of underweight did not change. Traditional methods of examining inequalities only at the clinical thresholds of overweight and obesity may have led the magnitude of inequalities in childhood BMI to be underestimated.
View details for DOI 10.1371/journal.pone.0147614
View details for Web of Science ID 000369528000044
View details for PubMedID 26812152
Limitations of GCTA as a solution to the missing heritability problem
PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA
2016; 113 (1): E61-E70
Genome-wide association studies (GWASs) seek to understand the relationship between complex phenotype(s) (e.g., height) and up to millions of single-nucleotide polymorphisms (SNPs). Early analyses of GWASs are commonly believed to have "missed" much of the additive genetic variance estimated from correlations between relatives. A more recent method, genome-wide complex trait analysis (GCTA), obtains much higher estimates of heritability using a model of random SNP effects correlated between genotypically similar individuals. GCTA has now been applied to many phenotypes from schizophrenia to scholastic achievement. However, recent studies question GCTA's estimates of heritability. Here, we show that GCTA applied to current SNP data cannot produce reliable or stable estimates of heritability. We show first that GCTA depends sensitively on all singular values of a high-dimensional genetic relatedness matrix (GRM). When the assumptions in GCTA are satisfied exactly, we show that the heritability estimates produced by GCTA will be biased and the standard errors will likely be inaccurate. When the population is stratified, we find that GRMs typically have highly skewed singular values, and we prove that the many small singular values cannot be estimated reliably. Hence, GWAS data are necessarily overfit by GCTA which, as a result, produces high estimates of heritability. We also show that GCTA's heritability estimates are sensitive to the chosen sample and to measurement errors in the phenotype. We illustrate our results using the Framingham dataset. Our analysis suggests that results obtained using GCTA, and the results' qualitative interpretations, should be interpreted with great caution.
View details for DOI 10.1073/pnas.1520109113
View details for Web of Science ID 000367520400011
View details for PubMedCentralID PMC4711841
Diabetic Phenotypes and Late-Life Dementia Risk A Mechanism-specific Mendelian Randomization Study
ALZHEIMER DISEASE & ASSOCIATED DISORDERS
2016; 30 (1): 15-20
Mendelian Randomization (MR) studies have reported that type 2 diabetes (T2D) was not associated with Alzheimer disease (AD). We adopted a modified, mechanism-specific MR design to explore this surprising result.Using inverse-variance weighted MR analysis, we evaluated the association between T2D and AD using data from 39 single nucleotide polymorphisms (SNPs) significantly associated with T2D in DIAbetes Genetics Replication And Meta-analysis (DIAGRAM) and the corresponding associations of each SNP with AD risk obtained from the International Genomics of Alzheimer's Project (IGAP, n=17,008 AD cases and n=37,154 controls). We evaluated mechanism-specific genetic subscores, including β-cell function, insulin sensitivity, and adiposity, and repeated analyses in 8501 Health and Retirement Study participants for replication and model validation.In IGAP, the overall T2D polygenic score did not predict AD [odds ratio (OR) for the T2D polygenic score=1.01; 95% confidence interval (CI), 0.96, 1.06] but the insulin sensitivity polygenic score predicted higher AD risk (OR=1.17; 95% CI, 1.02, 1.34). In the Health and Retirement Study, polygenic scores were associated with T2D risk; the associations between insulin sensitivity genetic polygenic score and cognitive phenotypes were not statistically significant.Evidence from polygenic scores suggests that insulin sensitivity specifically may affect AD risk, more than T2D overall.
View details for DOI 10.1097/WAD.0000000000000128
View details for Web of Science ID 000373515000003
View details for PubMedID 26650880
Shape of the association between income and mortality: a cohort study of Denmark, Finland, Norway and Sweden in 1995 and 2003
2016; 6 (12)
Prior work has examined the shape of the income-mortality association, but work has not compared gradients between countries. In this study, we focus on changes over time in the shape of income-mortality gradients for 4 Nordic countries during a period of rising income inequality. Context and time differentials in shape imply that the relationship between income and mortality is not fixed.Population-based cohort study of Denmark, Finland, Norway and Sweden.We collected data on individuals aged 25 or more in 1995 (n=12.98 million individuals, 0.84 million deaths) and 2003 (n=13.08 million individuals, 0.90 million deaths). We then examined the household size equivalised disposable income at the baseline year in relation to the rate of mortality in the following 5 years.A steep income gradient in mortality in men and women across all age groups except the oldest old in Denmark, Finland, Norway and Sweden. From the 1990s to 2000s mortality dropped, but generally more so in the upper part of the income distribution than in the lower part. As a consequence, the shape of the income gradient in mortality changed. The shift in the shape of the association was similar in all 4 countries.A non-linear gradient exists between income and mortality in most cases and because of a more rapid mortality decline among those with high income the income gradient has become steeper over time.
View details for DOI 10.1136/bmjopen-2015-010974
View details for Web of Science ID 000391303600105
View details for PubMedID 28011804
View details for PubMedCentralID PMC5223725
- Correlates of poor glycemic control among patients with diabetes initiating hemodialysis for end-stage renal disease BMC NEPHROLOGY 2015; 16
Poverty, Pregnancy, and Birth Outcomes: A Study of the Earned Income Tax Credit
PAEDIATRIC AND PERINATAL EPIDEMIOLOGY
2015; 29 (5): 444-452
Economic interventions are increasingly recognised as a mechanism to address perinatal health outcomes among disadvantaged groups. In the US, the earned income tax credit (EITC) is the largest poverty alleviation programme. Little is known about its effects on perinatal health among recipients and their children. We exploit quasi-random variation in the size of EITC payments to examine the effects of income on perinatal health.The study sample includes women surveyed in the 1979 National Longitudinal Survey of Youth (n = 2985) and their children born during 1986-2000 (n = 4683). Outcome variables include utilisation of prenatal and postnatal care, use of alcohol and tobacco during pregnancy, term birth, birthweight, and breast-feeding status. We first examine the health effects of both household income and EITC payment size using multivariable linear regressions. We then employ instrumental variables analysis to estimate the causal effect of income on perinatal health, using EITC payment size as an instrument for household income.We find that EITC payment size is associated with better levels of several indicators of perinatal health. Instrumental variables analysis, however, does not reveal a causal association between household income and these health measures.Our findings suggest that associations between income and perinatal health may be confounded by unobserved characteristics, but that EITC income improves perinatal health. Future studies should continue to explore the impacts of economic interventions on perinatal health outcomes, and investigate how different forms of income transfers may have different impacts.
View details for DOI 10.1111/ppe.12211
View details for Web of Science ID 000359633400010
View details for PubMedID 26212041
View details for PubMedCentralID PMC4536129
Racial/Ethnic Disparities in Inadequate Gestational Weight Gain Differ by Pre-pregnancy Weight
MATERNAL AND CHILD HEALTH JOURNAL
2015; 19 (8): 1672-1686
Pre-pregnancy body mass index (BMI) varies by race/ethnicity and modifies the association between gestational weight gain (GWG) and adverse pregnancy outcomes, which disproportionately affect racial/ethnic minorities. Yet studies investigating whether racial/ethnic disparities in GWG vary by pre-pregnancy BMI are inconsistent, and none studied nationally representative populations. Using categorical measures of GWG adequacy based on Institute of Medicine recommendations, we investigated whether associations between race/ethnicity and GWG adequacy were modified by pre-pregnancy BMI [underweight (<18.5 kg/m(2)), normal weight (18.5-24.9 kg/m(2)), overweight (25.0-29.9 kg/m(2)), or obese (≥30.0 kg/m(2))] among all births to Black, Hispanic, and White mothers in the 1979 USA National Longitudinal Survey of Youth cohort (n = 6,849 pregnancies; range 1-10). We used generalized estimating equations, adjusted for marital status, parity, smoking during pregnancy, gestational age, and multiple measures of socioeconomic position. Effect measure modification between race/ethnicity and pre-pregnancy BMI was significant for inadequate GWG (Wald test p value = 0.08). Normal weight Black [risk ratio (RR) 1.34, 95 % confidence interval (CI) 1.18, 1.52] and Hispanic women (RR 1.33, 95 % CI 1.15, 1.54) and underweight Black women (RR 1.38, 95 % CI 1.07, 1.79) experienced an increased risk of inadequate GWG compared to Whites. Differences in risk of inadequate GWG between minority women, compared to White women, were not significant among overweight and obese women. Effect measure modification between race/ethnicity and pre-pregnancy BMI was not significant for excessive GWG. The magnitude of racial/ethnic disparities in inadequate GWG appears to vary by pre-pregnancy weight class, which should be considered when designing interventions to close racial/ethnic gaps in healthy GWG.
View details for DOI 10.1007/s10995-015-1682-5
View details for Web of Science ID 000358064600003
Early-Life State-of-Residence Characteristics and Later Life Hypertension, Diabetes, and Ischemic Heart Disease.
American journal of public health
2015; 105 (8): 1689-1695
We examined how state characteristics in early life are associated with individual chronic disease later in life.We assessed early-life state of residence using the first 3 digits of social security numbers from blue- and white-collar workers from a US manufacturing company. Longitudinal data were available from 1997 to 2012, with 305 936 person-years of observation. Disease was assessed using medical claims. We modeled associations using pooled logistic regression with inverse probability of censoring weights.We found small but statistically significant associations between early-state-of-residence characteristics and later life hypertension, diabetes, and ischemic heart disease. The most consistent associations were with income inequality, percentage non-White, and education. These associations were similar after statistically controlling for individual socioeconomic and demographic characteristics and current state characteristics.Characteristics of the state in which an individual lives early in life are associated with prevalence of chronic disease later in life, with a strength of association equivalent to genetic associations found for these same health outcomes.
View details for DOI 10.2105/AJPH.2014.302547
View details for PubMedID 26066927
Leukocyte telomere length and mortality in the national health and nutrition examination survey, 1999-2002.
2015; 26 (4): 528-535
This study examined the association between leukocyte telomere length--a marker of cell aging--and mortality in a nationally representative sample of US adults ages 50-84 years. We also examined moderating effects of age, sex, race/ethnicity, and education.Data were from the National Health and Nutrition Examination Survey, 1999-2002 (n = 3,091). Cox proportional hazards regression was used to estimate the risk of all-cause and cause- specific mortality adjusting for sociodemographic characteristics, smoking, body mass index, and chronic conditions.Eight hundred and seventy deaths occurred over an average of 9.5 years of follow-up. In the full sample, a decrease of 1 kilobase pair in telomere length at baseline was marginally associated with a 10% increased hazard of all-cause mortality (hazard ratio [HR]: 1.1, 95% confidence interval [CI]: 0.9, 1.4) and a 30% increased hazard of death due to diseases other than cardiovascular disease or cancer (HR: 1.3, 95% CI: 0.9, 1.9). Among African-American but not white or Mexican-American respondents, a decrease of 1 kilobase pair in telomere length at baseline was associated with a two-fold increased hazard of cardiovascular mortality (HR: 2.0, 95% CI: 1.3, 3.1). There was no association between telomere length and cancer mortality.The association between leukocyte telomere length and mortality differs by race/ethnicity and cause of death.
View details for DOI 10.1097/EDE.0000000000000299
View details for PubMedID 26039272
Genetic vulnerability to diabetes and obesity: Does education offset the risk?
Social science & medicine
2015; 127: 150-158
The prevalence of type 2 diabetes (T2D) and obesity has recently increased dramatically. These common diseases are likely to arise from the interaction of multiple genetic, socio-demographic and environmental risk factors. While previous research has found genetic risk and education to be strong predictors of these diseases, few studies to date have examined their joint effects. This study investigates whether education modifies the association between genetic background and risk for type 2 diabetes (T2D) and obesity. Using data from non-Hispanic Whites in the Health and Retirement Study (HRS, n = 8398), we tested whether education modifies genetic risk for obesity and T2D, offsetting genetic effects; whether this effect is larger for individuals who have high risk for other (unobserved) reasons, i.e., at higher quantiles of HbA1c and BMI; and whether effects differ by gender. We measured T2D risk using Hemoglobin A1c (HbA1c) level, and obesity risk using body-mass index (BMI). We constructed separate genetic risk scores (GRS) for obesity and diabetes respectively based on the most current available information on the single nucleotide polymorphism (SNPs) confirmed as genome-wide significant predictors for BMI (29 SNPs) and diabetes risk (39 SNPs). Linear regression models with years of schooling indicate that the effect of genetic risk on HbA1c is smaller among people with more years of schooling and larger among those with less than a high school (HS) degree compared to HS degree-holders. Quantile regression models show that the GRS × education effect systematically increased along the HbA1c outcome distribution; for example the GRS × years of education interaction coefficient was -0.01 (95% CI = -0.03, 0.00) at the 10th percentile compared to -0.03 (95% CI = -0.07, 0.00) at the 90th percentile. These results suggest that education may be an important socioeconomic source of heterogeneity in responses to genetic vulnerability to T2D.
View details for DOI 10.1016/j.socscimed.2014.09.009
View details for PubMedID 25245452
Social disparities in heart disease risk and survivor bias among autoworkers: an examination based on survival models and g-estimation
OCCUPATIONAL AND ENVIRONMENTAL MEDICINE
2015; 72 (2): 138-144
To examine gender and racial disparities in ischaemic heart disease (IHD) mortality related to metalworking fluid exposures and in the healthy worker survivor effect.A cohort of white and black men and women autoworkers in the USA was followed from 1941 to 1995 with quantitative exposure to respirable particulate matter from water-based metalworking fluids. Separate analyses used proportional hazards models and g-estimation.The HR for IHD among black men was 3.29 (95% CI 1.49 to 7.31) in the highest category of cumulative synthetic fluid exposure. The HR for IHD among white women exposed to soluble fluid reached 2.44 (95% CI 0.96 to 6.22). However, no increased risk was observed among white men until we corrected for the healthy worker survivor effect. Results from g-estimation indicate that if white male cases exposed to soluble or synthetic fluid had been unexposed to that fluid type, then 1.59 and 1.20 years of life would have been saved on average, respectively.We leveraged the strengths of two different analytic approaches to examine the IHD risks of metalworking fluids. All workers may have the same aetiological risk; however, black and female workers may experience more IHD from water-based metalworking fluid exposure because of a steeper exposure-response or weaker healthy worker survivor effect.
View details for DOI 10.1136/oemed-2014-102168
View details for Web of Science ID 000347772900010
View details for PubMedID 25415971
Associations of cadmium and lead exposure with leukocyte telomere length: findings from national health and nutrition examination survey, 1999-2002.
American journal of epidemiology
2015; 181 (2): 127-136
Cadmium and lead are ubiquitous environmental contaminants that might increase risks of cardiovascular disease and other aging-related diseases, but their relationships with leukocyte telomere length (LTL), a marker of cellular aging, are poorly understood. In experimental studies, they have been shown to induce telomere shortening, but no epidemiologic study to date has examined their associations with LTL in the general population. We examined associations of blood lead and cadmium (n = 6,796) and urine cadmium (n = 2,093) levels with LTL among a nationally representative sample of US adults from the National Health and Nutrition Examination Survey (1999-2002). The study population geometric mean concentrations were 1.67 µg/dL (95% confidence interval (CI): 1.63, 1.70) for blood lead, 0.44 µg/L (95% CI: 0.42, 0.47) for blood cadmium, and 0.28 µg/L (95% CI: 0.27, 0.30) for urine cadmium. After adjustment for potential confounders, the highest (versus lowest) quartiles of blood and urine cadmium were associated with -5.54% (95% CI: -8.70, -2.37) and -4.50% (95% CI: -8.79, -0.20) shorter LTLs, respectively, with evidence of dose-response relationship (P for trend < 0.05). There was no association between blood lead concentration and LTL. These findings provide further evidence of physiological impacts of cadmium at environmental levels and might provide insight into biological pathways underlying cadmium toxicity and chronic disease risks.
View details for DOI 10.1093/aje/kwu293
View details for PubMedID 25504027
Socioeconomic disadvantage in childhood as a predictor of excessive gestational weight gain and obesity in midlife adulthood.
Emerging themes in epidemiology
2015; 12: 4-?
Lower childhood socioeconomic position is associated with greater risk of adult obesity among women, but not men. Pregnancy-related weight changes may contribute to this gender difference. The objectives of this study were to determine the associations between: 1. childhood socioeconomic disadvantage and midlife obesity; 2. excessive gestational weight gain (GWG) and midlife obesity; and 3. childhood socioeconomic disadvantage and excessive GWG, among a representative sample of childbearing women.We constructed marginal structural models for seven measures of childhood socioeconomic position for 4780 parous women in the United States, using National Longitudinal Survey of Youth (1979-2010) data. Institute of Medicine definitions were used for excessive GWG; body mass index ≥30 at age 40 defined midlife obesity. Analyses were separated by race/ethnicity. Additionally, we estimated controlled direct effects of childhood socioeconomic disadvantage on midlife obesity under a condition of never gaining excessively in pregnancy.Low parental education, but not other measures of childhood disadvantage, was associated with greater midlife obesity among non-black non-Hispanic women. Among black and Hispanic mothers, childhood socioeconomic disadvantage was not consistently associated with midlife obesity. Excessive GWG was associated with greater midlife obesity in all racial/ethnic groups. Childhood socioeconomic disadvantage was not statistically significantly associated with excessive GWG in any group. Controlled direct effects were not consistently weaker than total effects.Childhood socioeconomic disadvantage was associated with adult obesity, but not with excessive gestational weight gain, and only for certain disadvantage measures among non-black non-Hispanic mothers. Prevention of excessive GWG may benefit all groups through reducing obesity, but excessive GWG does not appear to serve as a mediator between childhood socioeconomic position and adult obesity in women.
View details for DOI 10.1186/s12982-015-0026-7
View details for PubMedID 25755672
- The EARN-Health Trial: protocol for a randomised controlled trial to identify health effects of a financial savings programme among low-income US adults. BMJ open 2015; 5 (10)
Correlates of poor glycemic control among patients with diabetes initiating hemodialysis for end-stage renal disease.
2015; 16: 204-?
Maintaining tight glycemic control is important for prevention of diabetes-related outcomes in end-stage renal disease patients with diabetes, especially in light of their poor prognosis. This study aimed to determine factors associated with poor glycemic control among U.S. patients with diabetes mellitus initiating hemodialysis for end-stage renal disease.Using data from the U.S. Renal Data System, electronic health records of a large national dialysis provider, and U.S. Census data, we performed a cross-sectional multivariable Poisson regression analysis to characterize risk factors associated with poor glycemic control, defined as glycated hemoglobin (HbA1c) > 7 vs. ≤ 7 %, in adult patients with diabetes who initiated hemodialysis at an outpatient facility between 2006 and 2011.Of 16,297 patients with diabetes, 21.2 % had HbA1c >7 %. In multivariable analysis, younger patients, patients of Native American race, and those of Hispanic ethnicity had higher prevalence of poor glycemic control. Independent correlates of poor glycemic control further included higher platelet count, white blood cell count, and ferritin; higher body mass index, systolic blood pressure, total cholesterol and triglyceride concentrations; lower HDL and albumin concentrations; lower normalized protein catabolic rate; and higher estimated glomerular filtration rate at initiation of dialysis (all P < 0.05). No independent associations were found with area-level socioeconomic indicators. Occurrence of diabetes in patients < 40 years of age, a proxy for type 1 diabetes, was associated with poor HbA1c control compared with that in patients ≥ 40 years of age, which was classified as type 2 diabetes. These findings were robust to the different outcome definitions of HbA1c > 7.5 % and > 8 %.In this cohort of incident end-stage renal disease patients with diabetes, poor glycemic control was independently associated with younger age, Native American race, Hispanic ethnicity, higher body mass index, and clinical risk factors including atherogenic lipoprotein profile, hypertension, inflammation, and markers indicative of malnutrition and a more serious systemic disease.
View details for DOI 10.1186/s12882-015-0204-4
View details for PubMedID 26645204
- Impact of a private sector living wage intervention on depressive symptoms among apparel workers in the Dominican Republic: a quasi-experimental study BMJ OPEN 2015; 5 (8)
The EARN-Health Trial: protocol for a randomised controlled trial to identify health effects of a financial savings programme among low-income US adults.
2015; 5 (10)
A theory within the social epidemiology field is that financial stress related to having inadequate financial savings may contribute to psychological stress, poor mental health and poor health-related behaviours among low-income US adults. Our objective is to test whether an intervention that encourages financial savings among low-income US adults improves health behaviours and mental health.A parallel group two-arm controlled superiority trial will be performed in which 700 participants will be randomised to the intervention or a wait list. The intervention arm will be provided an online Individual Development Account (IDA) for 6 months, during which participants receive a $5 incentive (£3.2, €4.5) for every month they save $20 in their account (£12.8, €18), and an additional $5 if they save $20 for two consecutive months. Both groups will be provided links to standard online financial counselling materials. Online surveys in months 0 (prior to randomisation), 6 and 12 (6 months postintervention) will assess self-reported health behaviours and mental health among participants in both arms. The surveys items were tested previously in the US Centers for Disease Control and Prevention national health interviews and related health studies, including self-reported overall health, health-related quality of life, alcohol and tobacco use, depression symptoms, financial stress, optimism and locus of control, and spending and savings behaviours. Trial data will be analysed on an intent-to-treat basis.This protocol was approved by the Institutional Review Board of Stanford University (Protocol ID: 30641). The findings of the trial will be disseminated through peer-reviewed publication.Identifier NCT02185612; Pre-results.
View details for DOI 10.1136/bmjopen-2015-009366
View details for PubMedID 26443663
View details for PubMedCentralID PMC4606428
Soda and cell aging: associations between sugar-sweetened beverage consumption and leukocyte telomere length in healthy adults from the national health and nutrition examination surveys.
American journal of public health
2014; 104 (12): 2425-2431
We tested whether leukocyte telomere length maintenance, which underlies healthy cellular aging, provides a link between sugar-sweetened beverage (SSB) consumption and the risk of cardiometabolic disease.We examined cross-sectional associations between the consumption of SSBs, diet soda, and fruit juice and telomere length in a nationally representative sample of healthy adults. The study population included 5309 US adults, aged 20 to 65 years, with no history of diabetes or cardiovascular disease, from the 1999 to 2002 National Health and Nutrition Examination Surveys. Leukocyte telomere length was assayed from DNA specimens. Diet was assessed using 24-hour dietary recalls. Associations were examined using multivariate linear regression for the outcome of log-transformed telomere length.After adjustment for sociodemographic and health-related characteristics, sugar-sweetened soda consumption was associated with shorter telomeres (b = -0.010; 95% confidence interval [CI] = -0.020, -0.001; P = .04). Consumption of 100% fruit juice was marginally associated with longer telomeres (b = 0.016; 95% CI = -0.000, 0.033; P = .05). No significant associations were observed between consumption of diet sodas or noncarbonated SSBs and telomere length.Regular consumption of sugar-sweetened sodas might influence metabolic disease development through accelerated cell aging.
View details for DOI 10.2105/AJPH.2014.302151
View details for PubMedID 25322305
- The association between a living wage and subjective social status and self-rated health: A quasi-experimental study in the Dominican Republic SOCIAL SCIENCE & MEDICINE 2014; 121: 91-97
The association between a living wage and subjective social status and self-rated health: a quasi-experimental study in the Dominican Republic.
Social science & medicine
2014; 121: 91-97
Poverty, both absolute and relative, is associated with poorer health. This is of particular concern in middle- and low-income countries facing a significant and growing burden of disease. There has been limited research specifically on whether interventions that increase income may foster better health outcomes. The establishment of a "living wage" apparel factory in the Dominican Republic provided a minimum income standard for factory workers, thus creating a natural experiment through which to study the effects of increased income on health indicators. The primary component of the intervention was a 350% wage increase, but apparel workers in the intervention factory also received education and professional development and were exposed to an enhanced occupational health and safety program. Workers at the intervention factory (n = 99) were compared with workers at a matched apparel factory (n = 105). Data were collected via in-person interviews in July and August of 2011, which was 15-16 months after workers were initially hired at the intervention site. Primary analyses used employment at the intervention factory as the independent variable and examined associations with two dependent variables: subjective social status and self-rated health. Results showed that receiving a 350% higher wage was associated with substantially higher subjective social status scores, as well as higher global and comparative self-rated health scores; effects were strongest in women. Subjective social status and self-rated health are associated with future health outcomes, so these results indicate that income increases for apparel workers may have positive long-term health outcomes, particularly for women.
View details for DOI 10.1016/j.socscimed.2014.09.051
View details for PubMedID 25442370
- A Multilevel Model of Postmenopausal Breast Cancer Incidence CANCER EPIDEMIOLOGY BIOMARKERS & PREVENTION 2014; 23 (10): 2078-2092
- Socioeconomic status and age at menarche: an examination of multiple indicators in an ethnically diverse cohort ANNALS OF EPIDEMIOLOGY 2014; 24 (10): 727-733
Socioeconomic status and age at menarche: an examination of multiple indicators in an ethnically diverse cohort.
Annals of epidemiology
2014; 24 (10): 727-733
Ethnic disparities exist in US girls' ages at menarche. Overweight and low socioeconomic status (SES) may contribute to these disparities but past research has been equivocal. We sought to determine which SES indicators were associated uniquely with menarche, for which ethnic groups, and whether associations operated through overweight.Using National Longitudinal Study of Youth data, we examined associations between SES indicators and age at menarche. Participants were 4851 girls and their mothers. We used survival analyses to examine whether SES, at various time points, was associated with menarche, whether body mass index mediated associations, and whether race/ethnicity modified associations.Black and Hispanic girls experienced menarche earlier than whites. After adjusting for SES, there was a 50% reduction in the effect estimate for "being Hispanic" and 40% reduction for "being black" versus "being white" on menarche. SES indicators were associated uniquely with earlier menarche, including mother's unmarried status and lower family income. Associations varied by race/ethnicity. Body mass index did not mediate associations.Racial differences in menarche may in large part be due to SES differences. Future experimental or quasiexperimental studies should examine whether intervening on SES factors could have benefits for delaying menarche among blacks and Hispanics.
View details for DOI 10.1016/j.annepidem.2014.07.002
View details for PubMedID 25108688
A multilevel model of postmenopausal breast cancer incidence.
Cancer epidemiology, biomarkers & prevention : a publication of the American Association for Cancer Research, cosponsored by the American Society of Preventive Oncology
2014; 23 (10): 2078-2092
Breast cancer has a complex etiology that includes genetic, biologic, behavioral, environmental, and social factors. Etiologic factors are frequently studied in isolation with adjustment for confounding, mediating, and moderating effects of other factors. A complex systems model approach may present a more comprehensive picture of the multifactorial etiology of breast cancer.We took a transdisciplinary approach with experts from relevant fields to develop a conceptual model of the etiology of postmenopausal breast cancer. The model incorporated evidence of both the strength of association and the quality of the evidence. We operationalized this conceptual model through a mathematical simulation model with a subset of variables, namely, age, race/ethnicity, age at menarche, age at first birth, age at menopause, obesity, alcohol consumption, income, tobacco use, use of hormone therapy (HT), and BRCA1/2 genotype.In simulating incidence for California in 2000, the separate impact of individual variables was modest, but reduction in HT, increase in the age at menarche, and to a lesser extent reduction in excess BMI >30 kg/m(2) were more substantial.Complex systems models can yield new insights on the etiologic factors involved in postmenopausal breast cancer. Modification of factors at a population level may only modestly affect risk estimates, while still having an important impact on the absolute number of women affected.This novel effort highlighted the complexity of breast cancer etiology, revealed areas of challenge in the methodology of developing complex systems models, and suggested additional areas for further study.
View details for DOI 10.1158/1055-9965.EPI-14-0403
View details for PubMedID 25017248
Excessive gestational weight gain over multiple pregnancies and the prevalence of obesity at age 40
INTERNATIONAL JOURNAL OF OBESITY
2014; 38 (5): 714-718
Although several studies have found an association between excessive gestational weight gain (GWG) and obesity later in life, to the best of our knowledge, no studies have explored the role of GWG events across the life course.We describe how the prevalence of midlife obesity (BMI⩾30 at age 40 or 41) among women varies by life course patterns of GWG (using 2009 IOM guidelines) in the USA's National Longitudinal Survey of Youth 1979 cohort.Among women who reported 1-3 births before age 40, the prevalence of midlife obesity increased with a rising number of excessive GWG events: from none (23.4%, n=875) to one (37.6%, n=707), from none (23.4%, n=875) to two (46.8%, n=427) and from none (23.4%, n=875) to three (54.6%, n=108), P<0.00005 for trend. Obesity prevalence was similar for the same number of excessive GWG events, regardless of parity. No clear pattern emerged for the sequencing of excessive GWG event(s) and later obesity.In our descriptive exploratory study, excessive GWG events appear to be associated with increased prevalence of obesity for parous women, suggesting the importance of preventive interventions regardless of timing of pregnancy-related weight changes over the life course.
View details for DOI 10.1038/ijo.2013.156
View details for Web of Science ID 000335445300014
View details for PubMedID 23958794
Seasonal Variation of Peripheral Blood Leukocyte Telomere Length in Costa Rica: A Population-Based Observational Study
AMERICAN JOURNAL OF HUMAN BIOLOGY
2014; 26 (3): 367-375
Peripheral blood leukocyte telomere length (LTL) is increasingly being used as a biomarker of aging, but its natural variation in human populations is not well understood. Several other biomarkers show seasonal variation, as do several determinants of LTL. We examined whether there was monthly variation in LTL in Costa Rica, a country with strong seasonal differences in precipitation and infection.We examined a longitudinal population-based cohort of 581 Costa Rican adults age 60 and above, from which blood samples were drawn between October 2006 and July 2008. LTL was assayed from these samples using the quantitative PCR method. Multivariate regression models were used to examine correlations between month of blood draw and LTL.Telomere length from peripheral blood leukocytes varied by as much as 200 base pairs depending on month of blood draw, and this difference is not likely to be due to random variation. A moderate proportion of this association is statistically accounted for by month and region specific average rainfall. We found shorter telomere length associated with greater rainfall.There are two possible explanations of our findings. First, there could be relatively rapid month-to-month changes in LTL. This conclusion would have implications for understanding the natural population dynamics of telomere length. Second, there could be seasonal differences in constituent cell populations. This conclusion would suggest that future studies of LTL use methods to account for the potential impact of constituent cell type. Am. J. Hum. Biol., 2014. © 2014 Wiley Periodicals, Inc.
View details for DOI 10.1002/ajhb.22529
View details for Web of Science ID 000334925200009
View details for PubMedID 24615938
Pregnancy and post-delivery maternal weight changes and overweight in preschool children.
2014; 60: 77-82
High maternal weight before and during pregnancy contributes to child obesity. To assess the additional role of weight change after delivery, we examined associations between pre- and post-pregnancy weight changes and preschooler overweight.Sample: 4359 children from the Children and Young Adults of the 1979 National Longitudinal Survey of Youth (NLSY) born to 2816 NLSY mothers between 1979 and 2006 and followed to age 4-5years old. Exposures: gestational weight gain (GWG) and post-delivery maternal weight change (PDWC). Outcome: child overweight (body mass index (BMI) ≥85th percentile).Adjusted models suggested that both increased GWG (OR: 1.08 per 5kg GWG, 95% CI: 1.01, 1.16) and excessive GWG (OR: 1.29 versus adequate GWG, 95% CI: 1.06, 1.56) were associated with preschooler overweight. Maternal weight change after delivery was also independently associated with child overweight (OR: 1.12 per 5kg PDWC, 95% CI: 1.04, 1.21). Associations were stronger among children with overweight or obese mothers.Increased maternal weight gain both during and after pregnancy predicted overweight in preschool children. Our results suggest that healthy post-pregnancy weight may join normal pre-pregnancy BMI and adequate GWG as a potentially modifiable risk factor for child overweight.
View details for DOI 10.1016/j.ypmed.2013.12.018
View details for PubMedID 24370455
- The Nonlinear Relationship Between Education and Mortality: An Examination of Cohort, Race/Ethnic, and Gender Differences POPULATION RESEARCH AND POLICY REVIEW 2013; 32 (6): 893-917
Systematic evaluation of environmental and behavioural factors associated with all-cause mortality in the United States National Health and Nutrition Examination Survey.
International journal of epidemiology
2013; 42 (6): 1795-1810
Environmental and behavioural factors are thought to contribute to all-cause mortality. Here, we develop a method to systematically screen and validate the potential independent contributions to all-cause mortality of 249 environmental and behavioural factors in the National Health and Nutrition Examination Survey (NHANES).We used Cox proportional hazards regression to associate 249 factors with all-cause mortality while adjusting for sociodemographic factors on data in the 1999-2000 and 2001-02 surveys (median 5.5 follow-up years). We controlled for multiple comparisons with the false discovery rate (FDR) and validated significant findings in the 2003-04 survey (median 2.8 follow-up years). We selected 249 factors from a set of all possible factors based on their presence in both the 1999-2002 and 2003-04 surveys and linkage with at least 20 deceased participants. We evaluated the correlation pattern of validated factors and built a multivariable model to identify their independent contribution to mortality.We identified seven environmental and behavioural factors associated with all-cause mortality, including serum and urinary cadmium, serum lycopene levels, smoking (3-level factor) and physical activity. In a multivariable model, only physical activity, past smoking, smoking in participant's home and lycopene were independently associated with mortality. These three factors explained 2.1% of the variance of all-cause mortality after adjusting for demographic and socio-economic factors.Our association study suggests that, of the set of 249 factors in NHANES, physical activity, smoking, serum lycopene and serum/urinary cadmium are associated with all-cause mortality as identified in previous studies and after controlling for multiple hypotheses and validation in an independent survey. Whereas other NHANES factors may be associated with mortality, they may require larger cohorts with longer time of follow-up to detect. It is possible to use a systematic association study to prioritize risk factors for further investigation.
View details for DOI 10.1093/ije/dyt208
View details for PubMedID 24345851
View details for PubMedCentralID PMC3887569
- Educational attainment and obesity: a systematic review OBESITY REVIEWS 2013; 14 (12): 989-1005
Longer leukocyte telomere length in Costa Rica's Nicoya Peninsula: A population-based study
2013; 48 (11): 1266-1273
Studies in humans suggest that leukocyte telomere length may act as a marker of biological aging. We investigated whether individuals in the Nicoya region of Costa Rica, known for exceptional longevity, had longer telomere length than those in other parts of the country. After controlling for age, age squared, rurality, rainy season and gender, the mean leukocyte telomere length in Nicoya was substantially longer (81 base pairs, p<0.05) than in other areas of Costa Rica, providing evidence of a biological pathway to which this notable longevity may be related. This relationship remains unchanged (79 base pairs, p<0.05) after statistically controlling for nineteen potential biological, dietary and social and demographic mediators. Thus the difference in the mean leukocyte telomere length that characterizes this unique region does not appear to be explainable by traditional behavioral and biological risk factors. More detailed examination of mean leukocyte telomere length by age shows that the regional telomere length difference declines at older ages.
View details for DOI 10.1016/j.exger.2013.08.005
View details for Web of Science ID 000325750900017
View details for PubMedID 23988653
View details for PubMedCentralID PMC3819141
Social isolation: a predictor of mortality comparable to traditional clinical risk factors.
American journal of public health
2013; 103 (11): 2056-2062
We explored the relationship between social isolation and mortality in a nationally representative US sample and compared the predictive power of social isolation with that of traditional clinical risk factors.We used data on 16,849 adults from the Third National Health and Nutrition Examination Survey and the National Death Index. Predictor variables were 4 social isolation factors and a composite index. Comparison predictors included smoking, obesity, elevated blood pressure, and high cholesterol. Unadjusted Kaplan-Meier tables and Cox proportional hazards regression models controlling for sociodemographic characteristics were used to predict mortality.Socially isolated men and women had worse unadjusted survival curves than less socially isolated individuals. Cox models revealed that social isolation predicted mortality for both genders, as did smoking and high blood pressure. Among men, individual social predictors included being unmarried, participating infrequently in religious activities, and lacking club or organization affiliations; among women, significant predictors were being unmarried, infrequent social contact, and participating infrequently in religious activities.The strength of social isolation as a predictor of mortality is similar to that of well-documented clinical risk factors. Our results suggest the importance of assessing patients' level of social isolation.
View details for DOI 10.2105/AJPH.2013.301261
View details for PubMedID 24028260
Maternal Pre-pregnancy BMI, Gestational Weight Gain, and Age at Menarche in Daughters
MATERNAL AND CHILD HEALTH JOURNAL
2013; 17 (8): 1391-1398
Life course theory suggests that early life experiences can shape health over a lifetime and across generations. Associations between maternal pregnancy experience and daughters' age at menarche are not well understood. We examined whether maternal pre-pregnancy BMI and gestational weight gain (GWG) were independently related to daughters' age at menarche. Consistent with a life course perspective, we also examined whether maternal GWG, birth weight, and prepubertal BMI mediated the relationship between pre-pregnancy BMI and daughter's menarcheal age. We examined 2,497 mother-daughter pairs from the 1979 National Longitudinal Survey of Youth. Survival analysis with Cox proportional hazards was used to estimate whether maternal pre-pregnancy overweight/obesity (BMI ≥ 25.0 kg/m(2)) and GWG adequacy (inadequate, recommended, and excessive) were associated with risk for earlier menarche among girls, controlling for important covariates. Analyses were conducted to examine the mediating roles of GWG adequacy, child birth weight and prepubertal BMI. Adjusting for covariates, pre-pregnancy overweight/obesity (HR = 1.20, 95 % CI 1.06, 1.36) and excess GWG (HR = 1.13, 95 % CI 1.01, 1.27) were associated with daughters' earlier menarche, while inadequate GWG was not. The association between maternal pre-pregnancy weight and daughters' menarcheal timing was not mediated by daughter's birth weight, prepubertal BMI or maternal GWG. Maternal factors, before and during pregnancy, are potentially important determinants of daughters' menarcheal timing and are amenable to intervention. Further research is needed to better understand pathways through which these factors operate.
View details for DOI 10.1007/s10995-012-1139-z
View details for Web of Science ID 000325024100008
View details for PubMedID 23054446
Invited Commentary: Off-Roading With Social Epidemiology-Exploration, Causation, Translation
AMERICAN JOURNAL OF EPIDEMIOLOGY
2013; 178 (6): 858-863
Population health improvements are the most relevant yardstick against which to evaluate the success of social epidemiology. In coming years, social epidemiology must increasingly emphasize research that facilitates translation into health improvements, with continued focus on macro-level social determinants of health. Given the evidence that the effects of social interventions often differ across population subgroups, systematic and transparent exploration of the heterogeneity of health determinants across populations will help inform effective interventions. This research should consider both biological and social risk factors and effect modifiers. We also recommend that social epidemiologists take advantage of recent revolutionary improvements in data availability and computing power to examine new hypotheses and expand our repertoire of study designs. Better data and computing power should facilitate underused analytic approaches, such as instrumental variables, simulation studies and models of complex systems, and sensitivity analyses of model biases. Many data-driven machine-learning approaches are also now computationally feasible and likely to improve both prediction models and causal inference in social epidemiology. Finally, we emphasize the importance of specifying exposures corresponding with realistic interventions and policy options. Effect estimates for directly modifiable, clearly defined health determinants are most relevant for building translational social epidemiology to reduce disparities and improve population health.
View details for DOI 10.1093/aje/kwt145
View details for Web of Science ID 000325150600005
View details for PubMedID 24008902
Were the mental health benefits of a housing mobility intervention larger for adolescents in higher socioeconomic status families?
Health & place
2013; 23: 79-88
Moving to Opportunity (MTO) was a social experiment to test how relocation to lower poverty neighborhoods influences low-income families. Using adolescent data from 4 to 7 year evaluations (aged 12-19, n=2829), we applied gender-stratified intent-to-treat and adherence-adjusted linear regression models, to test effect modification of MTO intervention effects on adolescent mental health. Low parental education, welfare receipt, unemployment and never-married status were not significant effect modifiers. Tailoring mobility interventions by these characteristics may not be necessary to alter impact on adolescent mental health. Because parental enrollment in school and teen parent status adversely modified MTO intervention effects on youth mental health, post-move services that increase guidance and supervision of adolescents may help support post-move adjustment.
View details for DOI 10.1016/j.healthplace.2013.05.002
View details for PubMedID 23792412
Parity and Body Mass Index in US Women: A Prospective 25-Year Study
2013; 21 (8): 1514-1518
Objective: To investigate long-term body mass index (BMI) changes with childbearing. Design and Methods: Adjusted mean BMI changes were estimated by race-ethnicity, baseline BMI and parity using longitudinal regression models in 3943 young females over 10 and 25 year follow-up from the ongoing 1979 National Longitudinal Survey of Youth cohort. Results: Estimated BMI increases varied by group, ranging from a low of 2.1 BMI units for white, non-overweight nulliparas over the first 10 years to a high of 10.1 BMI units for black, overweight multiparas over the full 25-year follow-up. Impacts of parity were strongest among overweight multiparas and primaparas at ten years, ranges 1.4-1.7 and 0.8-1.3 BMI units, respectively. Among non-overweight women at 10 years, parity-related gain varied by number of births among black and whites but was unassociated in Hispanic women. After 25 years, childbearing significantly increased BMI only among overweight multiparous black women. Conclusion: Childbearing is associated with permanent weight gain in some women, but the relationship differs by maternal BMI in young adulthood, number of births, race-ethnicity and length of follow-up. Given that overweight black women may be at special risk for accumulation of permanent, long-term weight after childbearing, effective interventions for this group are particularly needed.
View details for DOI 10.1002/oby.20503
View details for Web of Science ID 000323521500003
View details for PubMedID 23630108
Income Gains and Very Low-Weight Birth among Low-Income Black Mothers in California
BIODEMOGRAPHY AND SOCIAL BIOLOGY
2013; 59 (2): 141-156
We test the hypothesis suggested in the literature that an acute income gain in the form of the earned income tax credit reduces the odds of a very low-weight birth among low-income non-Hispanic black mothers. We apply ecological time series and supplemental individual-level logistic regression methods to monthly birth data from California between 1989 and 1997. Contrary to our hypothesis, the odds of very low-weight birth increases above its expected value two months after mothers typically receive the credit. We discuss our findings in relation to the epidemiologic literature concerned with ambient events during pregnancy and recommend further investigation.
View details for DOI 10.1080/19485565.2013.833802
View details for Web of Science ID 000326868400003
View details for PubMedID 24215256
Patient-physician interaction and quality of life in recently diagnosed breast cancer patients
BREAST CANCER RESEARCH AND TREATMENT
2013; 139 (2): 581-595
Few studies have explored how patient-physician interactions influence patients' quality of life (QOL). In a prospective cohort study of 1,855 women diagnosed with invasive breast cancer in the Kaiser Permanente Northern California Medical Care Program from 2006 to 2011, we examined associations between patient-physician interactions during cancer treatment and QOL, overall and by racial/ethnic group. Participants completed the interpersonal processes of care (IPC) survey at approximately 8 months post-diagnosis to assess specific domains of the patient-physician interaction during the months after cancer diagnosis. Domains included: compassion, elicited concerns, explained results, decided together, lack of clarity, discrimination due to race/ethnicity, and disrespectful office staff. The functional assessment of cancer therapy-breast cancer was completed concurrently to measure QOL. Linear regression models examined the association of IPC with QOL, first adjusting for patient covariates including age, race, clinical factors, and psychosocial measures and then for physician characteristics such as age, sex, race/ethnicity, and specialty. For all participants (n = 1,855), IPC scores suggesting greater lack of clarity, discrimination due to race/ethnicity, and disrespectful office staff in patient-physician interactions were associated with lower QOL (P< 0.01). IPC scores suggesting physicians demonstrating compassion, eliciting concerns, or explaining results were associated with higher QOL (P< 0.01). Among Whites (n = 1,306), only the associations with higher QOL remained. African Americans (n = 110) who reported higher scores on physician compassion and elicited concerns had higher QOL, whereas higher scores for disrespectful office staff had lower QOL. No associations were observed among Asians (n = 201) and Hispanics (n = 186). After further adjustment for physician factors, the associations among Whites remained, whereas those among African Americans disappeared. In the breast cancer treatment setting, characteristics of the patient-physician interaction as perceived by the patient are associated with QOL, yet were not specific to patient race/ethnicity.
View details for DOI 10.1007/s10549-013-2569-z
View details for Web of Science ID 000321069600028
View details for PubMedID 23715629
Employment status and quality of life in recently diagnosed breast cancer survivors
2013; 22 (6): 1411-1420
BACKGROUND: Breast cancer survivors are less likely to be employed than similar healthy women, yet effects of employment on the well being of survivors are largely unknown. In a prospective cohort study of 2013 women diagnosed from 2006 to 2011 with invasive breast cancer in Kaiser Permanente Northern California, we describe associations between hours worked per week and change in employment with quality of life (QOL) from diagnosis through active treatment. METHODS: Participants completed information on employment status and QOL approximately 2 and 8 months post-diagnosis. QOL was assessed by the Functional Assessment of Cancer Therapy-Breast Cancer. Multivariable linear regression models were adjusted for potential confounders including demographic, diagnostic, and medical care factors to examine associations between employment and QOL. RESULTS: At baseline, overall well being was higher for women who worked at least some hours per week compared with women who were not working. Women working 1-19 h/week at baseline also had higher functional well being compared with women who were not working. There was a significant, positive association between hours worked per week and physical and social well being. At the 6-month follow-up, women working at least 20 h/week had higher physical and functional well being than those who were not working. Lower scores for physical and functional well being were observed among women who stopped working during the 6-month follow-up period. CONCLUSIONS: Continuing to work after a breast cancer diagnosis may be beneficial to multiple areas of QOL. Strategies to help women continue working through treatment should be explored. Copyright © 2012 John Wiley & Sons, Ltd.
View details for DOI 10.1002/pon.3157
View details for Web of Science ID 000320105500029
View details for PubMedID 22912069
Socioeconomic status, health behavior, and leukocyte telomere length in the National Health and Nutrition Examination Survey, 1999-2002
SOCIAL SCIENCE & MEDICINE
2013; 85: 1-8
The purpose of this study was to examine the association between socioeconomic status (SES) and leukocyte telomere length (LTL) - a marker of cell aging that has been linked to stressful life circumstances - in a nationally representative, socioeconomically and ethnically diverse sample of US adults aged 20-84. Using data from the National Health and Nutrition Examination Survey (NHANES), 1999-2002, we found that respondents who completed less than a high school education had significantly shorter telomeres than those who graduated from college. Income was not associated with LTL. African-Americans had significantly longer telomeres than whites, but there were no significant racial/ethnic differences in the association between education and telomere length. Finally, we found that the association between education and LTL was partially mediated by smoking and body mass index but not by drinking or sedentary behavior.
View details for DOI 10.1016/j.socscimed.2013.02.023
View details for Web of Science ID 000317880300001
View details for PubMedID 23540359
Chronic Psychological Stress and Racial Disparities in Body Mass Index Change Between Black and White Girls Aged 10-19
ANNALS OF BEHAVIORAL MEDICINE
2013; 45 (1): 3-12
One of the largest health disparities in the USA is in obesity rates between Black and White females.The objective of this study was to test the hypothesis that the stress-obesity link is stronger in Black females than in White females aged 10-19.Multilevel modeling captured the dynamic of acute (1 month) and chronic (10 years) stress and body mass index (BMI; weight in kilograms divided by height in meters squared) change in the National Heart, Lung, and Blood Institute Growth and Health Study, which consists of 2,379 Black and White girls across a span of socioeconomic status. The girls were assessed longitudinally from ages 10 to 19.Higher levels of stress during the 10 years predicted significantly greater increases in BMI over time compared to lower levels of stress. This relationship was significantly stronger for Black compared to White girls.Psychological stress is a modifiable risk factor that may moderate early racial disparities in BMI.
View details for DOI 10.1007/s12160-012-9398-x
View details for Web of Science ID 000314293300002
View details for PubMedID 22993022
Education and obesity at age 40 among American adults
SOCIAL SCIENCE & MEDICINE
2013; 78: 34-41
Although many have studied the association between educational attainment and obesity, studies to date have not fully examined prior common causes and possible interactions by race/ethnicity or gender. It is also not clear if the relationship between actual educational attainment and obesity is independent of the role of aspired educational attainment or expected educational attainment. The authors use generalized linear log link models to examine the association between educational attainment at age 25 and obesity (BMI≥30) at age 40 in the USA's National Longitudinal Survey of Youth 1979 cohort, adjusting for demographics, confounders, and mediators. Race/ethnicity but not gender interacted with educational attainment. In a complete case analysis, after adjusting for socioeconomic covariates from childhood, adolescence, and adulthood, among whites only, college graduates were less likely than high school graduates to be obese (RR = 0.69, 95%CI: 0.57, 0.83). The risk ratio remained similar in two sensitivity analyses when the authors adjusted for educational aspirations and educational expectations and analyzed a multiply imputed dataset to address missingness. This more nuanced understanding of the role of education after controlling for a thorough set of confounders and mediators helps advance the study of social determinants of health and risk factors for obesity.
View details for DOI 10.1016/j.socscimed.2012.11.025
View details for Web of Science ID 000314739300005
View details for PubMedID 23246398
The Nicoya region of Costa Rica: a high longevity island for elderly males.
Vienna yearbook of population research
2013; 11: 109-136
Reliable data show that the Nicoyan region of Costa Rica is a hot spot of high longevity. A survival follow-up of 16,300 elderly Costa Ricans estimated a Nicoya death rate ratio (DRR) for males 1990-2011 of 0.80 (0.69-0.93 CI). For a 60-year-old Nicoyan male, the probability of becoming centenarian is seven times that of a Japanese male, and his life expectancy is 2.2 years greater. This Nicoya advantage does not occur in females, is independent of socio-economic conditions, disappears in out-migrants and comes from lower cardiovascular (CV) mortality (DRR = 0.65). Nicoyans have lower levels of biomarkers of CV risk; they are also leaner, taller and suffer fewer disabilities. Two markers of ageing and stress-telomere length and dehydroepiandrosterone sulphate-are also more favourable. The Nicoya diet is prosaic and abundant in traditional foods like rice, beans and animal protein, with low glycemic index and high fibre content.
View details for PubMedID 25426140
- Quantile Regression for Hypothesis Testing and Hypothesis Screening at the Dawn of Big Data EPIDEMIOLOGY 2012; 23 (5): 665-667
Discrepancy between objective and subjective measures of job stress and sickness absence
SCANDINAVIAN JOURNAL OF WORK ENVIRONMENT & HEALTH
2010; 36 (6): 449-457
The aim of this study was to examine the association of the discrepancy between externally and self-assessed measures of work environment with long- and short-term sickness absence.The study population included 6997 middle-aged men and women from the Whitehall II cohort, whose work characteristics were examined at baseline (1985-1988) through both an external evaluation and self-report, with a follow-up of up to 13 years of sickness absence reporting from administrative records. The primary exposure of interest was the discrepancy between measures of work stress for fast job pace, conflicting demands, and decision latitude.In mutually adjusted models, external measures of job characteristics were more strongly associated with higher rates of sickness absence compared with self-assessed measures, for both lower frequency of fast work pace and lower conflicting demands (i.e., "passive" levels). Individuals who self-reported higher frequencies of fast work pace and conflicting demands than were reported through external assessment had higher rates of short-term sickness absence [incident rate ratios (IRR) of 1.13 (95% confidence interval [95% CI] 1.11-1.15) and IRR 1.14 (95% CI 1.11-1.16), respectively]. There was no difference in rates of sickness absence found for decision latitude [IRR 1.02 (95% CI 1.00-1.04)].Our findings demonstrate that the discrepancy between externally and self-assessed job demand measures have additional predictive power beyond each individual measure of job structure, which may be related to the extent of cognitive and emotional processing of assessment questions as compared to decision latitude measures.
View details for Web of Science ID 000283701800004
View details for PubMedID 20725704
Differences in the association of cardiovascular risk factors with education: a comparison of Costa Rica (CRELES) and the USA (NHANES)
JOURNAL OF EPIDEMIOLOGY AND COMMUNITY HEALTH
2010; 64 (9): 821-828
Despite different levels of economic development, Costa Rica and the USA have similar mortalities among adults. However, in the USA there are substantial differences in mortality by educational attainment, and in Costa Rica there are only minor differences. This contrast motivates an examination of behavioural and biological correlates underlying this difference.The authors used data on adults aged 60 and above from the Costa Rican Longevity and Healthy Ageing Study (CRELES) (n=2827) and from the US National Health and Nutrition Examination Survey (NHANES) (n=5607) to analyse the cross-sectional association between educational level and the following risk factors for cardiovascular disease (CVD): ever smoked, current smoker, sedentary, high saturated fat, high carbohydrates, high calorie diet, obesity, severe obesity, large waist circumference, HDL cholesterol, LDL cholesterol, triglycerides, hemoglobin A1c, fasting glucose, C-reactive protein, systolic blood pressure and BMI.There were significantly fewer hazardous levels of risk biomarkers at higher levels of education for more than half (10 out of 17) of the risk factors in the USA, but for less than a third of the outcomes in Costa Rica (five out of 17).These results are consistent with the context-specific nature of educational differences in risk factors for CVD and with a non-uniform nature of association of CVD risk factors with education within countries. Our results also demonstrate that social equity in mortality is achieved without uniform equity in all risk factors.
View details for DOI 10.1136/jech.2009.086926
View details for Web of Science ID 000281308900016
View details for PubMedID 19822554
The association of earnings with health in middle age: Do self-reported earnings for the previous year tell the whole story?
SOCIAL SCIENCE & MEDICINE
2010; 71 (3): 431-439
Research on earnings and health frequently relies on self-reported earnings (SRE) for a single year, despite repeated criticism of this measure. We use 31 years (1961-1991) of earnings recorded by the United States Social Security Administration (SSA) to predict the 1992 prevalence of disability, diabetes, stroke, heart disease, cancer, depression and death by 2002 in a subset of Health and Retirement Study participants (n = 5951). We compare odds ratios (ORs) for each health outcome associated with self-reported or administratively recorded earnings. Individuals with no 1991 SSA earnings had worse health in multiple domains than those with positive earnings. However, this association diminished as the time lag between earnings and health increased, so that the absence of earnings before approximately 1975 did not predict health in 1992. Among those with positive earnings, lengthening the lag between SSA earnings and health did not significantly diminish the magnitude of the association with diabetes, heart disease, stroke, or death. Longer lags did reduce but did not eliminate the association between earnings and both disability and depression. Despite theoretical limitations of single year SRE, there were no statistically significant differences between the ORs estimated with single-year SRE and those estimated with a 31-year average of SSA earnings. For example, a one unit increase in logged SRE for 1991 predicted a 19% reduction in the odds of dying by 2002 (OR = 0.81; 95% confidence interval: 0.72,0.90), while a similar increase in average SSA earnings for 1961-1991 had an OR of 0.72 (0.63, 0.82). The point estimates for the OR associated with 31 year average SSA earnings were further from the null than the ORs associated with single year SRE for heart disease, depression, and death, and closer to the null for disability, diabetes, and stroke, but none of these differences was statistically significant.
View details for DOI 10.1016/j.socscimed.2010.03.045
View details for Web of Science ID 000280120100002
View details for PubMedID 20580858
Association of maternal gestational weight gain with short- and long-term maternal and child health outcomes.
American journal of obstetrics and gynecology
2010; 202 (6): 574 e1-8
The purpose of this study was to investigate the associations between gestational weight gain (GWG) and small- and large-for-gestational-age (SGA, LGA), cesarean delivery, child overweight, and maternal postpartum weight retention in a diverse sample of women in the Unites States.We estimated associations between GWG (continuous and within categories defined by the Institute of Medicine), maternal prepregnancy body mass index, and each outcome in 4496 births in the National Longitudinal Survey of Youth 1979, which was a prospective cohort.GWG (kilograms) was associated with decreased risk of SGA and increased risk of LGA, cesarean delivery, postpartum weight retention, and child overweight independent of maternal demographic and pregnancy characteristics. Gain above the Institute of Medicine guidelines was associated with decreased risk of SGA and increased risk of all other outcomes.Excessive gain may have long-term consequences for maternal and child body size, but the benefits of lower gain must be balanced against risk of SGA.
View details for DOI 10.1016/j.ajog.2009.12.007
View details for PubMedID 20132923
- Commentary: It's not all means and genes-socio-economic position, variation and genetic confounding INTERNATIONAL JOURNAL OF EPIDEMIOLOGY 2010; 39 (2): 415-416
Biologic Risk Markers for Coronary Heart Disease Nonlinear Associations With Income
2010; 21 (1): 38-46
It is unclear whether a linear relationship is an appropriate description of the association between income and biologic markers of coronary heart disease risk. Stronger associations at certain levels of income would have implications for underlying mechanisms.The study is based on a healthy sample of 25-64 year olds (n = 14,022) from a nationally representative cross-sectional study (the 1988-1994 United States Third National Health and Nutrition Examination Survey). We use regression splines to model the shape of the association between income and 8 biologic markers for coronary heart disease risk, controlling for age, race/ethnicity, marital status, and education.Substantial income-biomarker associations were found for 5 outcomes among women (HDL cholesterol, triglycerides, C-reactive protein, systolic blood pressure, and venous blood lead) and for 3 outcomes among men (HDL cholesterol, triglycerides, and venous blood lead). The most common shapes of association were a stronger association at lower income levels and a greater risk level of biomarker near median income.We find that the associations of income with biologic risk markers are often nonlinear. The differences in the shape of association suggest there are multiple pathways through which income is associated with coronary heart disease risk.
View details for DOI 10.1097/EDE.0b013e3181c30b89
View details for Web of Science ID 000272872900009
View details for PubMedID 20010209
Socioeconomic gradients in health in international and historical context
BIOLOGY OF DISADVANTAGE: SOCIOECONOMIC STATUS AND HEALTH
2010; 1186: 24-36
This article places socioeconomic gradients in health into a broader international and historical context. The data we present supports the conclusion that current socioeconomic gradients in health within the United States are neither inevitable nor immutable. This literature reveals periods in the United States with substantially smaller gradients, and identifies many examples of other countries whose different social policy choices appear to have led to superior health levels and equity even with fewer aggregate resources. The article also sheds light on the potential importance of various hypothesized mechanisms in driving major shifts in U.S. population health patterns. While it is essential to carefully examine individual mechanisms contributing to health patterns, it is also illuminating to take a more holistic view of the set of factors changing in conjunction with major shifts in population health. In this article, we do so by focusing on the period of the 1980s, during which U.S. life expectancy gains slowed markedly relative to other developed countries, and U.S. health disparities substantially increased. A comparison with Canada suggests that exploring broad social policy differences, such as the weaker social safety net in the United States, may be a promising area for future investigation.
View details for DOI 10.1111/j.1749-6632.2009.05384.x
View details for Web of Science ID 000277908000003
View details for PubMedID 20201866
Socioeconomic status in relation to early menarche among black and white girls
CANCER CAUSES & CONTROL
2009; 20 (5): 713-720
Early menarche is a risk factor for breast cancer. We investigated the variation in age at menarche by socioeconomic status (SES) and race.A cohort study was conducted on 1,091 black and 986 white girls from the three sites in the United States as part of the NHLBI Growth and Health Study (NGHS), who were aged 9-10 years at baseline and followed through adolescence over a 10-year period with annual exams. Using logistic regression models, we evaluated the nature and strength of associations between two socioeconomic indicators (household income and parental education) and early menarche (<12 years old) unadjusted and adjusted for anthropometry and maternal age at menarche.Proportionately, more black girls were menarcheal before 12 years of age compared to their white counterparts (46%, n = 468 vs. 26%, n = 240, respectively, p < 0.0001). Parental education was not a significant predictor of early menarche. The graded association between household income and age at menarche was strong and significant among black girls but less clear among white girls. Compared with those in the lowest quartile of household income, white girls in the highest quartile were at a significantly lower risk of early menarche [adjusted odds ratio (OR) = 0.37, 95% confidence intervals (CIs) 0.18-0.80]. The inverse was true for black girls: those in the highest quartile of household income were at an increased risk of early menarche (adjusted OR = 2.15, 95% CI 1.27-3.63)The SES factor selected (household income versus parental education) affected the findings regarding racial differences in the timing of menarche. It will be important for future studies to elucidate the link between household income and age at menarche in developed countries.
View details for DOI 10.1007/s10552-008-9284-9
View details for Web of Science ID 000266340200023
View details for PubMedID 19107561
- Life course priorities among Appalacian emerging adults: revisiting Wallace's organization of diversity Ethos 2009; 37 (2): 225-242
The non-linear risk of mortality by income level in a healthy population: US National Health and Nutrition Examination Survey mortality follow-up cohort, 1988-2001
BMC PUBLIC HEALTH
An examination of where in the income distribution income is most strongly associated with risk of mortality will provide guidance for identifying the most critical pathways underlying the connections between income and mortality, and may help to inform public health interventions to reduce socioeconomic disparities. Prior studies have suggested stronger associations at the lower end of the income distribution, but these studies did not have detailed categories of income, were unable to exclude individuals whose declining health may affect their income and did not use methods to determine exact threshold points of non-linearity. The purpose of this study is to describe the non-linear risks of all-cause and cause-specific mortality across the income distribution.We examined potential non-linear risk of mortality by family income level in a population that had not retired early, changed jobs, or changed to part-time work due to health reasons, in order to minimize the effects of illness on income. We used data from the US National Health and Nutrition Examination Survey (1988-1994), among individuals age 18-64 at baseline, with mortality follow-up to the year 2001 (ages 25-77 at the end of follow-up, 106 037 person-years of time at risk). Differential risk of mortality was examined using proportional hazard models with penalized regression splines in order to allow for non-linear associations between mortality risk and income, controlling for age, race/ethnicity, marital status, level of educational attainment and occupational category.We observed significant non-linear risks of all-cause mortality, as well as for certain specific causes of death at different levels of income. Typically, risk of mortality decreased with increasing income levels only among persons whose family income was below the median; above this level, there was little decreasing risk of mortality with higher levels of income. There was also some variation in mortality risk at different levels of income by cause and gender.The majority of the income associated mortality risk in individuals between the ages of 18-77 in the United States is among the population whose family income is below the median (equal to $20,190 in 1991, 3.2 times the poverty level). Efforts to decrease socioeconomic disparities may have the greatest impact if focused on this population.
View details for DOI 10.1186/1471-2458-8-383
View details for Web of Science ID 000261409300001
View details for PubMedID 19000311
Depression among Latinos in the United States: A meta-analytic review
JOURNAL OF CONSULTING AND CLINICAL PSYCHOLOGY
2008; 76 (3): 355-366
The authors conducted a meta-analytic review to assess the prevalence of major depressive disorder and depressive symptoms among Latinos compared with non-Latino Whites in the United States using community-based data. Random-effects estimates were calculated for 8 studies meeting inclusion criteria that reported lifetime prevalence of major depressive disorder (combined N = 76,270) and for 23 studies meeting inclusion criteria that reported current prevalence of depressive symptoms (combined N = 38,997). Findings did not indicate a group difference in lifetime prevalence of major depressive disorder (odds ratio = 0.89, 95% confidence interval = 0.72, 1.10). Latinos reported more depressive symptoms than non-Latino Whites (standardized mean difference = 0.19, 95% confidence interval = 0.12, 0.25); however, this effect was small and does not appear to suggest a clinically meaningful preponderance of depressive symptoms among Latinos. Findings are examined in the context of theories on vulnerability and resilience, and recommendations for future research are discussed.
View details for DOI 10.1037/0022-006X.76.3.355
View details for Web of Science ID 000256326700001
View details for PubMedID 18540730
The fall and rise of US inequities in premature mortality: 1960-2002
2008; 5 (2): 227-241
Debates exist as to whether, as overall population health improves, the absolute and relative magnitude of income- and race/ethnicity-related health disparities necessarily increase-or decrease. We accordingly decided to test the hypothesis that health inequities widen-or shrink-in a context of declining mortality rates, by examining annual US mortality data over a 42 year period.Using US county mortality data from 1960-2002 and county median family income data from the 1960-2000 decennial censuses, we analyzed the rates of premature mortality (deaths among persons under age 65) and infant death (deaths among persons under age 1) by quintiles of county median family income weighted by county population size. Between 1960 and 2002, as US premature mortality and infant death rates declined in all county income quintiles, socioeconomic and racial/ethnic inequities in premature mortality and infant death (both relative and absolute) shrank between 1966 and 1980, especially for US populations of color; thereafter, the relative health inequities widened and the absolute differences barely changed in magnitude. Had all persons experienced the same yearly age-specific premature mortality rates as the white population living in the highest income quintile, between 1960 and 2002, 14% of the white premature deaths and 30% of the premature deaths among populations of color would not have occurred.The observed trends refute arguments that health inequities inevitably widen-or shrink-as population health improves. Instead, the magnitude of health inequalities can fall or rise; it is our job to understand why.
View details for DOI 10.1371/journal.pmed.0050046
View details for Web of Science ID 000254928800014
View details for PubMedID 18303941
US disparities in health: Descriptions, causes, and mechanisms
ANNUAL REVIEW OF PUBLIC HEALTH
2008; 29: 235-252
Eliminating health disparities is a fundamental, though not always explicit, goal of public health research and practice. There is a burgeoning literature in this area, but a number of unresolved issues remain. These include the definition of what constitutes a disparity, the relationship of different bases of disadvantage, the ability to attribute cause from association, and the establishment of the mechanisms by which social disadvantage affects biological processes that get into the body, resulting in disease. We examine current definitions and empirical research on health disparities, particularly disparities associated with race/ethnicity and socioeconomic status, and discuss data structures and analytic strategies that allow causal inference about the health impacts of these and associated factors. We show that although health is consistently worse for individuals with few resources and for blacks as compared with whites, the extent of health disparities varies by outcome, time, and geographic location within the United States. Empirical work also demonstrates the importance of a joint consideration of race/ethnicity and social class. Finally, we discuss potential pathways, including exposure to chronic stress and resulting psychosocial and physiological responses to stress, that serve as mechanisms by which social disadvantage results in health disparities.
View details for DOI 10.1146/annurev.publhealth.29.020907.090852
View details for Web of Science ID 000255349400018
View details for PubMedID 18031225
Socioeconomic position and the metabolic syndrome in early, middle, and late life: Evidence from NHANES 1999-2002
ANNALS OF EPIDEMIOLOGY
2007; 17 (10): 782-790
To evaluate whether there is an association between socioeconomic position (SEP) and the metabolic syndrome at various ages, including adolescent, middle-aged and older participants in gender-specific analyses.Participants were from the 1999-2002 National Health and Nutrition Examination Survey. SEP was measured by income and years of education. Metabolic syndrome was measured in adults using the American Heart Association guidelines and in adolescents using methods based on national reference data. Cross-sectional multivariable-adjusted logistic regression analyses were performed.In women aged 25 to 45 and 46 to 65 years, income below the poverty line (poverty income ratio [PIR] less than one) was associated with higher odds of metabolic syndrome compared with PIR greater than 3 (odds ratio [OR] = 4.90; 95% confidence interval (CI) = 2.24, 10.71, and OR = 2.54; CI = 1.38, 4.67, for the respective age groups) after adjustment for age, race/ethnicity, and menopause. Similar findings were observed for educational attainment. In adolescents, older adults (aged >65 years), and males, income and education were not related to the metabolic syndrome.This report demonstrates that SEP is associated with the metabolic syndrome in females aged 25 to 65 years and is less strongly associated in males, adolescents, or older participants. These findings provide physiologic mechanistic evidence linking SEP to risk for coronary heart disease.
View details for DOI 10.1016/j.annepidem.2007.05.003
View details for Web of Science ID 000250067200005
View details for PubMedID 17697786
Socioeconomic disparities in metabolic syndrome differ by gender: Evidence from NHANES III
ANNALS OF EPIDEMIOLOGY
2007; 17 (1): 19-26
The aim of the study is to examine whether socioeconomic position (SEP) is associated with metabolic syndrome and whether the association differs by gender and race/ethnicity.Study participants were from the Third National Health and Nutrition Examination Survey. SEP was measured by using education and poverty income ratio (PIR). Metabolic syndrome was measured according to the National Institutes of Health guidelines. Multivariable-adjusted logistic regression analyses were performed.Low education (<12 years) was associated with metabolic syndrome in women (odds ratio [OR], 1.77; 95% confidence interval [CI], 1.39-2.24) and less so in men (OR, 1.27; 95% CI, 0.97-1.66) versus more than 12 years of education. For income, low PIR (
View details for DOI 10.1016/j.annepidem.2006.07.002
View details for Web of Science ID 000243281300003
View details for PubMedID 17140811
Monitoring socioeconomic disparities in death: Comparing individual-level education and area-based socioeconomic measures
AMERICAN JOURNAL OF PUBLIC HEALTH
2006; 96 (12): 2135-2138
We compared all-cause mortality rates stratified by individual-level education and by census tract area-based socioeconomic measures for Massachusetts (1999-2001). Among persons aged 25 and older, the age-adjusted relative index of inequality was slightly higher for the census tract than for the individual education measures (1.5 vs 1.2, respectively). Only the census tract socioeconomic measures could provide a relative index of inequality (2-3) for deaths before age 25 or detect expected socioeconomic disparities for deaths among persons 65 and older (relative index of inequality= approximately 1.2 vs 0.8 for census tract measures and individual education, respectively).
View details for DOI 10.2105/AJPH.2005.075408
View details for Web of Science ID 000242474500010
View details for PubMedID 16809582
Comparing individual- and area-based socioeconomic measures for the surveillance of health disparities: A multilevel analysis of Massachusetts births, 1989-1991
AMERICAN JOURNAL OF EPIDEMIOLOGY
2006; 164 (9): 823-834
The absence of individual-level socioeconomic information in most US health surveillance data necessitates using area-based socioeconomic measures (ABSMs) to monitor health inequalities. Using the 1989-1991 birth weight data from Massachusetts, the authors compared estimates of health disparities detected with census tract- and block group-level ABSMs pertaining to poverty and education, as well as parental education, both independently and together. In separate models, adjusted for infant's sex, mother's age, and parents' race/ethnicity, worst-off categories of census tract ABSMs and parental education had a comparable birth weight deficit of approximately 70 g. Similar results were observed for low birth weight (<2,500 g), with worst-off categories of census tract ABSMs and parental education having an odds ratio of approximately 1.37 (p < 0.001). In mutually adjusted models for birth weight and low birth weight, census tract ABSMs still detected an effect estimate nearly 50% of that detected by parental education. Additionally, census tract ABSMs detected socioeconomic gradients in birth weight among births to mothers aged less than 25 years, an age group in which educational attainment is unlikely to be completed. These results suggest that aptly chosen ABSMs can be used to monitor socioeconomic inequalities in health. The risk, if any, in the absence of individual-level socioeconomic information is a conservative estimate of socioeconomic inequalities in health.
View details for DOI 10.1093/aje/kwj313
View details for Web of Science ID 000241432000002
View details for PubMedID 16968866
Mapping and measuring social disparities in premature mortality: The impact of census tract poverty within and across Boston neighborhoods, 1999-2001
JOURNAL OF URBAN HEALTH-BULLETIN OF THE NEW YORK ACADEMY OF MEDICINE
2006; 83 (6): 1063-1084
The identification and documentation of health disparities are important functions of public health surveillance. These disparities, typically falling along lines defined by gender, race/ethnicity, and social class, are often made visible in urban settings as geographic disparities in health between neighborhoods. Recognizing that premature mortality is a powerful indicator of disparities in both health status and access to health care that can readily be monitored using routinely available public health surveillance data, we undertook a systematic analysis of spatial variation in premature mortality in Boston (1999-2001) across neighborhoods and sub-neighborhoods in relation to census tract (CT) poverty. Using a multilevel model based framework, we estimated that the incidence of premature mortality was 1.39 times higher (95% credible interval 1.09-1.78) among persons living in the most economically deprived CTs (>/=20% below poverty) compared to those in the least impoverished tracts (<5% below poverty). We present maps of model-based standardized mortality ratios that show substantial within-neighborhood variation in premature mortality and a sizeable decrease in spatial variation after adjustment for CT poverty. Additionally, we present maps of model-based direct standardized rates that can more readily be compared to externally published rates and targets, as well as maps of the population attributable fraction that show that in some of Boston's poorest neighborhoods, the proportion of excess deaths associated with CT poverty reaches 25-30%. We recommend that these methods be incorporated into routine analyses of public health surveillance data to highlight continuing social disparities in premature mortality.
View details for DOI 10.1007/s11524-006-9089-7
View details for Web of Science ID 000243181900007
View details for PubMedID 17001522
Race/ethnicity and changing US socioeconomic gradients in breast cancer incidence: California and Massachusetts, 1978-2002 (United States)
CANCER CAUSES & CONTROL
2006; 17 (2): 217-226
We tested the hypothesis that the US socioeconomic gradient in breast cancer incidence is declining, with the decline most pronounced among racial/ethnic groups with the highest incidence rates.We geocoded the invasive incident breast cancer cases for three US population-based cancer registries covering: Los Angeles County, CA (1978-1982, 1988-1992, 1998-2002; n = 68,762 cases), the San Francisco Bay Area, CA (1978-1982, 1988-1992, 1998-2002; n = 37,210 cases) and Massachusetts (1988-1992, 1998-2002; n = 48,111 cases), linked the records to census tract area-based socioeconomic measures, and, for each socioeconomic stratum, computed average annual breast cancer incidence rates for the 5-year period straddling the 1980, 1990, and 2000 census, overall and by race/ethnicity and gender.Our findings indicate that the socioeconomic gradient in breast cancer incidence is: (a) relatively small (at most 1.2) and stable among US white non-Hispanic and black women; (b) sharper and generally increasing among Hispanic and Asian and Pacific Islander American women; and (c) cannot be meaningfully analyzed without considering effect modification by race/ethnicity and immigration.Our results indicate that secular changes in US socioeconomic gradients in breast cancer incidence exist and vary by race/ethnicity.
View details for DOI 10.1007/s10552-005-0408-1
View details for Web of Science ID 000234754500011
View details for PubMedID 16425100
The association between suicide and the socio-economic characteristics of geographical areas: a systematic review
2006; 36 (2): 145-157
Despite an extensive literature, there have been widely divergent findings regarding the direction of the association between area socio-economic characteristics and area suicide rates, with high-quality studies finding either a direct relation (higher rates of suicide in higher socio-economic areas), an inverse relation (lower rates of suicide in higher socio-economic areas) or no association.We performed a systematic review of the literature dating from 1897 to 2004 and identified 86 publications with 221 separate analyses that met our inclusion criteria. We examined the percent of direct, inverse and null findings stratified by key study characteristics including size of aggregated area, socio-economic measure used, region of study, control variables and study design.Analyses at the community level are significantly more likely to demonstrate lower rates of suicide among higher socio-economic areas than studies using larger areas of aggregation. Measures of area poverty and deprivation are most likely to be inversely associated with suicide rates and median income is least likely to be inversely associated with suicide rates. Analyses using measures of unemployment and education and occupation were equally likely to demonstrate inverse associations. Study results did not vary significantly by gender or by study design.The heterogeneity of associations is mostly accounted for by study design features that have largely been neglected in this literature. Enhanced attention to size of region and measurement strategies provide a clearer picture of how suicide rates vary by region. Resources for suicide prevention should be targeted to high poverty/deprivation and high unemployment areas.
View details for DOI 10.1017/S003329170500588X
View details for Web of Science ID 000235200800001
View details for PubMedID 16420711
Painting a truer picture of US socioeconomic and racial/ethnic health inequalities: The public health disparities geocoding project
AMERICAN JOURNAL OF PUBLIC HEALTH
2005; 95 (2): 312-323
We describe a method to facilitate routine monitoring of socioeconomic health disparities in the United States.We analyzed geocoded public health surveillance data including events from birth to death (c. 1990) linked to 1990 census tract (CT) poverty data for Massachusetts and Rhode Island.For virtually all outcomes, risk increased with CT poverty, and when we adjusted for CT poverty racial/ethnic disparities were substantially reduced. For half the outcomes, more than 50% of cases would not have occurred if population rates equaled those of persons in the least impoverished CTs. In the early 1990s, persons in the least impoverished CT were the only group meeting Healthy People 2000 objectives a decade ahead.Geocoding and use of the CT poverty measure permit routine monitoring of US socioeconomic inequalities in health, using a common and accessible metric.
View details for DOI 10.2105/AJPH.2003.032482
View details for Web of Science ID 000226851000030
View details for PubMedID 15671470
Racial disparities-in context: A multilevel analysis of neighborhood variations in poverty and excess mortality among black populations in Massachusetts
AMERICAN JOURNAL OF PUBLIC HEALTH
2005; 95 (2): 260-265
We analyzed neighborhood heterogeneity in associations among mortality, race/ethnicity, and area poverty.We performed a multilevel statistical analysis of Massachusetts all-cause mortality data for the period 1989 through 1991 (n=142836 deaths), modeled as 79813 cells (deaths and denominators cross-tabulated by age, gender, and race/ethnicity) at level 1 nested within 5532 block groups at level 2 within 1307 census tracts (CTs) at level 3. We also characterized CTs by percentage of the population living below poverty level.Neighborhood variation in mortality across CTs and block groups was not accounted for by these areas' age, gender, and racial/ethnic composition. Neighborhood variation in mortality was much greater for the Black population than for the White population, largely because of CT-level variation in poverty rates.Neighborhood heterogeneity in the relationship between mortality and race/ethnicity in Massachusetts is statistically significant and is closely related to CT-level variation in poverty.
View details for DOI 10.2105/AJPH.2003.034132
View details for Web of Science ID 000226851000022
View details for PubMedID 15671462
Evaluating vancomycin use at a pediatric hospital: New approaches and insights
INFECTION CONTROL AND HOSPITAL EPIDEMIOLOGY
2005; 26 (1): 47-55
To characterize vancomycin use at a pediatric tertiary-care hospital, to discriminate between initial (< or = 72 hours) and prolonged (> 72 hours) inappropriate use, and to define patient characteristics associated with inappropriate use.Vancomycin courses were retrospectively reviewed using an algorithm modeled on HICPAC guidelines. Data were collected regarding patient demographics, comorbidities, other medication use, and nosocomial infections. The association between each variable and the outcome of inappropriate use was determined by longitudinal regression analysis. A multivariable model was constructed to assess risk factors for inappropriate initial and prolonged vancomycin use.A pediatric tertiary-care medical center.Children older than 1 year who received intravenous vancomycin from November 2000 to June 2001.Three hundred twenty-seven vancomycin courses administered to 260 patients were evaluated for appropriateness. Of initial courses, 114 (35%) were considered inappropriate. Of 143 prolonged courses, 103 (72%) were considered inappropriate. Multivariable risk factor analysis identified the following variables as significantly associated with inappropriate initial use: admission to the surgery service, having a malignancy, receipt of a stem cell transplant, and having received a prior inappropriate course of vancomycin. No variables were identified as significant risk factors for inappropriate prolonged use.Substantial inappropriate use of vancomycin was identified. Prolonged inappropriate use was a particular problem. This risk factor analysis suggests that interventions targeting patients admitted to certain services or receiving multiple courses of vancomycin could reduce inappropriate use.
View details for Web of Science ID 000226369700007
View details for PubMedID 15693408
Race/ethnicity, gender, and monitoring socioeconomic gradients in health: A comparison of area-based socioeconomic measures - The public health disparities geocoding project
AMERICAN JOURNAL OF PUBLIC HEALTH
2003; 93 (10): 1655-1671
Use of multilevel frameworks and area-based socioeconomic measures (ABSMs) for public health monitoring can potentially overcome the absence of socioeconomic data in most US public health surveillance systems. To assess whether ABSMs can meaningfully be used for diverse race/ethnicity-gender groups, we geocoded and linked public health surveillance data from Massachusetts and Rhode Island to 1990 block group, tract, and zip code ABSMs. Outcomes comprised death, birth, cancer incidence, tuberculosis, sexually transmitted infections, childhood lead poisoning, and nonfatal weapons-related injuries. Among White, Black, and Hispanic women and men, measures of economic deprivation (e.g., percentage below poverty) were most sensitive to expected socioeconomic gradients in health, with the most consistent results and maximal geocoding linkage evident for tract-level analyses.
View details for Web of Science ID 000185881100016
View details for PubMedID 14534218
Assessing health impact assessment: multidisciplinary and international perspectives
JOURNAL OF EPIDEMIOLOGY AND COMMUNITY HEALTH
2003; 57 (9): 659-662
Health impact assessment (HIA) seeks to expand evaluation of policy and programmes in all sectors, both private and public, to include their impact on population health. While the idea that the public's health is affected by a broad array of social and economic policies is not new and dates back well over two centuries, what is new is the notion-increasingly adopted by major health institutions, such as the World Health Organisation (WHO) and the United Kingdom National Health Services (NHS)-that health should be an explicit consideration when evaluating all public policies. In this article, it is argued that while HIA has the potential to enhance recognition of societal determinants of health and of intersectoral responsibility for health, its pitfalls warrant critical attention. Greater clarity is required regarding criteria for initiating, conducting, and completing HIA, including rules pertaining to decision making, enforcement, compliance, plus paying for their conduct. Critical debate over the promise, process, and pitfalls of HIA needs to be informed by multiple disciplines and perspectives from diverse people and regions of the world.
View details for Web of Science ID 000184853800008
View details for PubMedID 12933768
Identification, characterization, and functional analysis of a gene encoding the ferric uptake regulation protein in Bartonella species
JOURNAL OF BACTERIOLOGY
2001; 183 (19): 5751-5755
Environmental iron concentrations coordinately regulate transcription of genes involved in iron acquisition and virulence via the ferric uptake regulation (fur) system. We identified and sequenced the fur gene and flanking regions of three Bartonella species. The most notable difference between Bartonella Fur and other Fur proteins was a substantially higher predicted isoelectric point. No promoter activity or Fur autoregulation was detected using a gfp reporter gene fused to the 204 nucleotides immediately upstream of the Bartonella fur gene. Bartonella henselae fur gene expression complemented a Vibrio cholerae fur mutant.
View details for Web of Science ID 000170958900035
View details for PubMedID 11544240
View details for PubMedCentralID PMC95469
Transcriptional mapping and RNA processing of the Plasmodium falciparum mitochondrial mRNAs
MOLECULAR AND BIOCHEMICAL PARASITOLOGY
2000; 105 (1): 91-103
The mitochondrial genome of Plasmodium falciparum encodes three protein coding genes and highly fragmented rRNAs. The genome is polycistronically transcribed and, since gene-size transcripts are much more abundant than the polycistronic transcripts, the latter are presumably cleaved to produce the smaller, mature mRNAs and rRNAs. Mapping the transcripts of the P. falciparum mitochondrial protein coding genes shows that the 3' end of each gene directly abuts the 5' end of the gene located immediately downstream. The 5' ends of the protein coding genes are also closely apposed to adjacent genes, with one directly abutting a gene on the same DNA strand and two others separated by just 13 nt from an rDNA fragment encoded on the opposite strand. These mapping data are consistent with production of the mRNAs by cleavage from a polycistronic precursor transcript. Further processing of the mRNAs comes from addition of oligo(A) tails. Unexpectedly, the presence and length of such tails varies in a gene-specific fashion. In this regard, polyadenylation of the P. falciparum mitochondrial mRNAs is more similar to that seen for the P. falciparum mitochondrial rRNAs than that of mitochondrial mRNAs in other organisms.
View details for Web of Science ID 000084168400009
View details for PubMedID 10613702
The fragmented mitochondrial ribosomal RNAs of Plasmodium falciparum have short A tails
NUCLEIC ACIDS RESEARCH
1999; 27 (11): 2416-2422
The mitochondrial genome of Plasmodium falciparum encodes highly fragmented rRNAs. Twenty small RNAs which are putative rRNA fragments have been found and 15 of them have been identified as corresponding to specific regions of rRNA sequence. To investigate the possible interactions between the fragmented rRNAs in the ribosome, we have mapped the ends of many of the small transcripts using primer extension and RNase protection analysis. Results obtained from these studies revealed that some of the rRNA transcripts were longer than the sequences which encode them. To investigate these size discrepancies, we performed 3' RACE PCR analysis and RNase H mapping. These analyses revealed non-encoded oligo(A) tails on some but not all of these small rRNAs. The approximate length of the oligo(A) tail appears to be transcript-specific, with some rRNAs consistently showing longer oligo(A) tails than others. The oligoadenylation of the rRNAs may provide a buffer zone against 3' exonucleolytic attack, thereby preserving the encoded sequences necessary for secondary structure interactions in the ribosome.
View details for Web of Science ID 000080678100025
View details for PubMedID 10325433
- The sta-1 mutation prevents assembly of starch granules in nitrogen-starved cells and serves as a useful morphological marker during sexual reproduction in Chlamydomonas monoica Journal of Phycology 1998; 34 (1): 147-151
The Plasmodium falciparum 6 kb element is polycistronically transcribed
MOLECULAR AND BIOCHEMICAL PARASITOLOGY
1996; 81 (2): 211-223
The Plasmodium falciparum 6 kb element encodes three protein coding genes and highly fragmented large and small subunit rRNAs; its gene content makes it the probable mitochondrial genome. Many of the genes are encoded so close to each other that there is insufficient room for specific promoters upstream of each gene. RNase protection analysis of two rRNA fragments whose genes are adjacent provided evidence for a polycistronic transcript containing sequences from both, as well as separate small RNAs. To evaluate the possibility of further polycistronic transcription, several sets of oligonucleotide primers located in different regions of the 6 kb element were employed to amplify cDNAs. These analyses have revealed the existence of 6 kb element transcripts as long as 5.9 kb. Both mRNA and rRNA sequences are included on these putative precursor transcripts. Since these types of RNA are known to have different patterns of abundance changes during the erythrocytic portion of the parasite life cycle, RNA stability is presumably an important feature in regulating mitochondrial transcript abundance.
View details for Web of Science ID A1996VM86500009
View details for PubMedID 8898336