Publications

  • Hypertensive Disorders in Pregnancy: Differences by Hispanic Ethnicity and Black Race. Journal of racial and ethnic health disparities Atkinson, J. A., Carmichael, S. L., Leonard, S. A. 2024

    Abstract

    Black individuals carry the greatest burden of maternal mortality, with hypertensive disorders during pregnancy being a significant driving force to this disparity. However, research on maternal health disparities predominantly groups Hispanic Black individuals with all other individuals of Hispanic ethnicity. We hypothesized that this aggregation might obscure the risk patterns of hypertensive disorders in pregnancy for Hispanic-Black and non-Hispanic Black individuals.We analyzed a California statewide dataset of vital records linked to hospitalization discharge data for births from 2007 to 2018. Using multivariable logistic regression models adjusted for age, pre-pregnancy BMI, parity, smoking status, diabetes, and chronic renal disease, we compared the odds of hypertensive disorders in pregnancy between Hispanic Black, non-Hispanic Black, and non-Black Hispanic racial-ethnic groups. Hypertensive disorders were categorized into two groups: (1) any hypertensive disorder and (2) chronic hypertension alone, non-severe hypertensive disorders, and severe hypertensive disorders in pregnancy.Non-Hispanic Black people had 75% increased odds of developing a hypertensive disorder during pregnancy (adjusted odds ratio (aOR); 95% confidence interval (CI): 1.74, 1.78) and Hispanic-Black individuals had a 31% increased odds (95% CI: 1.24, 1.38) as compared with non-Black Hispanic individuals. When considering hypertensive disorders separately, the race-associated differences were largest for chronic hypertension alone, with non-Hispanic Black individuals showing an aOR of 2.35 (95% CI: 2.32, 2.38) and Hispanic-Black individuals an aOR of 1.80 (95% CI: 1.66, 1.95).Compared with non-Black Hispanic individuals, the prevalence of hypertensive disorders in pregnancy was higher in Black-Hispanic individuals and highest in non-Hispanic Black individuals. Racial/ethnic differences were larger for chronic hypertension alone than for preeclampsia.

    View details for DOI 10.1007/s40615-024-02224-5

    View details for PubMedID 39499430

    View details for PubMedCentralID 10144523

  • Historical Redlining, Contemporary Gentrification, and Severe Maternal Morbidity in California, 2005-2018. JAMA network open Gao, X., Morello-Frosch, R., Nuru-Jeter, A. M., Snowden, J. M., Carmichael, S. L., Mujahid, M. S. 2024; 7 (9): e2429428

    Abstract

    Historically redlined neighborhoods may experience disinvestment, influencing their likelihood of gentrification, a process of neighborhood (re-)development that unequally distributes harms and benefits by race and class. Understanding the combined outcomes of redlining and gentrification informs how the mutually constitutive systems of structural racism and racial capitalism affect pregnancy outcomes.To examine if historical redlining and contemporary gentrification is associated with increased severe maternal morbidity (SMM) odds.This cross-sectional study used data from a statewide population-based sample of all live hospital births at 20 weeks' gestation or more between 2005 and 2018 in California. Analysis was conducted from March 2023 to January 2024.Redlining (as characterized by the federal Home Owners' Loan Corporation mortgage security maps) and displacement (using present-day sociodemographic and housing market information).Mixed-effects logistic regression models were used to assess the association of census tract-level exposure to historical redlining and contemporary gentrification with increased SMM odds, adjusting for sociodemographic and pregnancy related factors. Outcome classification was based on the Centers for Disease Control and Prevention SMM index, which defines SMM as having any of the 21 procedures and diagnoses based on the International Classification of Diseases, Ninth Revision and International Statistical Classification of Diseases and Related Health Problems, Tenth Revision codes.The study sample included 1 554 837 births (median [SD] maternal age, 29.0 [6.4] years; 3464 American Indian or Alaskan Native [0.2%], 224 774 Asian [14.5%], 132 240 Black [8.5%], 880 104 Hispanic [56.6%], 312 490 White [20.1%]), with 22 993 cases of SMM (1.4%). Residents in historically redlined neighborhoods that were undergoing gentrification or displacement were more likely to be Black, Hispanic, and American Indian or Alaskan Native. Independent of individual-level characteristics, SMM odds were greater for individuals living in redlined neighborhoods that experienced displacement (OR, 1.21; 95% CI, 1.14-1.28) and in redlined neighborhoods undergoing gentrification (OR, 1.21; 95% CI, 1.13-1.29) compared with those in continuously advantaged neighborhoods.Findings from this cross-sectional study demonstrate that the legacies of redlining, intertwined with current dynamics of displacement and gentrification, affect SMM. Place-based sociopolitical mechanisms that inequitably distribute resources may be important intervention points to address structural drivers of adverse pregnancy outcomes and their racial inequities.

    View details for DOI 10.1001/jamanetworkopen.2024.29428

    View details for PubMedID 39312242

    View details for PubMedCentralID PMC11420692

  • Survival of Children With Critical Congenital Heart Defects in the National Birth Defects Prevention Study. Birth defects research Forestieri, N. E., Olshan, A. F., Oster, M. E., Ailes, E. C., Fundora, M. P., Fisher, S. C., Shumate, C., Romitti, P. A., F Liberman, R., Nembhard, W. N., Carmichael, S. L., Desrosiers, T. A. 2024; 116 (9): e2394

    Abstract

    Critical congenital heart defects (CCHDs) are associated with considerable morbidity and mortality. This study estimated survival of children with nonsyndromic CCHDs and evaluated relationships between exposures of interest and survival by CCHD severity (univentricular or biventricular function).This analysis included 4380 infants with CCHDs (cases) born during 1999-2011 and enrolled in the National Birth Defects Prevention Study, a multisite, population-based case-control study of major birth defects. Cases were linked to state death files. Nonparametric Kaplan-Meier survival functions were used to estimate 1- and 5-year survival probabilities overall and by severity group (univentricular/biventricular) stratified by demographic and clinical exposure variables of interest. The log-rank test was used to determine whether stratified survival curves were equivalent. Survival and 95% confidence intervals (CIs) were also estimated using Cox proportional hazards modeling adjusted for maternal age, education, race/ethnicity, study site, and birth year.One- and five-year survival rates were 85.8% (CI 84.7-86.8) and 83.7% (CI 82.5-84.9), respectively. Univentricular 5-year survival was lower than biventricular case survival [65.3% (CI 61.7-68.5) vs. 89.0% (CI 87.8-90.1; p < 0.001)]. Clinical factors (e.g. preterm birth, low birthweight, and complex/multiple defects) were associated with lower survival in each severity group. Sociodemographic factors (non-Hispanic Black race/ethnicity,

    View details for DOI 10.1002/bdr2.2394

    View details for PubMedID 39258453

  • Association of nutritional intake with clinical and imaging activity in pediatric multiple sclerosis MULTIPLE SCLEROSIS JOURNAL Mohan, S. D., Peterson, S., Brenton, J., Carmichael, S. L., Virupakshaiah, A., Rodriguez, M., Tillema, J., Mar, S., Rensel, M. R., Abrams, A., Chitnis, T., Benson, L., Gorman, M., Lotze, T., Shukla, N., Graves, J., Aaen, G., Casper, T., Waubant, E. 2024: 1056-1065

    Abstract

    Understanding nutrition's role in multiple sclerosis (MS) can guide recommendations and intervention-based studies.Evaluate the association between nutrition and pediatric-onset MS outcomes.Prospective longitudinal multicenter study conducted as part of the US Network of Pediatric MS centers. Predictors were collected using a food screener estimating intake of various dietary food groups (e.g. dairy and fruits) and additional calculated indices (e.g. Healthy Eating Index (HEI)). Outcomes included time-from-enrollment to clinical relapse, new magnetic resonance imaging (MRI) T2 lesions, and Expanded Disability Status Scale (EDSS) increase.353 children with MS were enrolled (mean ± SD age 15.4 ± 2.9, follow-up 3.9 ± 2.6 years). Multivariable analysis demonstrated that increased dairy by 50% of recommended intake was associated with increased relapse risk by 41% (adjusted hazard ratio (HR) 1.41, 95% CI 1.07-1.86), and risk of T2 progression by 40% (1.40, 1.12-1.74). Increased intake of fruit or vegetable above recommended, and every five-point HEI increase decreased relapse risk by 25% (0.75, 0.60-0.95), 45% (0.55, 0.32-0.96), and 15% (0.84, 0.74-0.96), respectively. No associations were found with EDSS.This work supports the influence of dietary intake on MS course, particularly with dairy intake. Future prospective study is required to establish causation.

    View details for DOI 10.1177/13524585241261556

    View details for Web of Science ID 001279795900001

    View details for PubMedID 39078111

  • A Counterfactual Analysis of Impact of Cesarean Birth in a First Birth on Severe Maternal Morbidity in the Subsequent Birth. Epidemiology (Cambridge, Mass.) Bane, S., Snowden, J. M., Simard, J. F., Odden, M., Kan, P., Main, E. K., Carmichael, S. L. 2024

    Abstract

    It is known that cesarean birth affects maternal outcomes in subsequent pregnancies, but specific effect estimates are lacking. We sought to quantify the effect of cesarean birth reduction among nulliparous, term, singleton, vertex (NTSV) births (i.e., preventable cesarean births) on severe maternal morbidity (SMM) in the second birth.We examined birth certificates linked with maternal hospitalization data (2007-19) from California for NTSV births with a second birth (N = 779,382). The exposure was cesarean delivery in first birth and the outcome was SMM in the second birth. We used adjusted Poisson regression models to calculate risk ratios and population attributable fraction for SMM in the second birth and conducted a counterfactual impact analysis to estimate how lowering NTSV cesarean births could reduce SMM in second birth.The adjusted risk ratio for SMM in the second birth given a prior cesarean birth was 1.7 (95% CI 1.5-1.9); 15.5% (95% CI 15.3%-15.7%) of this SMM may be attributable to prior cesarean birth. In a counterfactual analysis where 12% of the California population least likely to get a cesarean birth instead delivered vaginally, we observed 174 fewer SMM events in a population of individuals with a low-risk first birth and a subsequent birth.In our counterfactual analysis, lowering primary cesarean birth among a NTSV population was associated with fewer downstream SMM events in subsequent births and overall. Additionally, our findings reflect the importance of considering the cumulative accrual of risks across the reproductive life-course.

    View details for DOI 10.1097/EDE.0000000000001775

    View details for PubMedID 39058553

  • Considering pregnancies as repeated versus independent events: An empirical comparison of common approaches across selected perinatal outcomes. American journal of obstetrics & gynecology MFM Bane, S., Carmichael, S. L., Mathur, M. B., Simard, J. F. 2024: 101434

    Abstract

    In population-based research, pregnancy may be a repeated event. Despite published guidance on how to address repeated pregnancies to the same individual, a variety of approaches are observed in perinatal epidemiological studies. While some of these approaches are supported by the chosen research question, others are consequences of constraints inherent to a given dataset (e.g., missing parity information). These decisions determine how appropriately a given research question can be answered and overall generalizability.To compare common cohort selection and analytic approaches used for perinatal epidemiological research by assessing the prevalence of two perinatal outcomes and their association with a clinical and a social independent variable STUDY DESIGN: Using vital records linked to maternal hospital discharge records for singleton births, we created four cohorts: (1) all-births (2) randomly selected one birth per individual (3) first observed birth per individual (4) primiparous-births (parity 1). Sampling of births was not conditional on cluster (i.e., we did not sample all births by a given mother, but rather sampled individual births). Study outcomes were severe maternal morbidity and preeclampsia/eclampsia, and the independent variables were self-reported race/ethnicity (as a social factor) and systemic lupus erythematosus. Comparing the four cohorts, we assessed the distribution of maternal characteristics, the prevalence of outcomes, overall and stratified by parity, and risk ratios for the associations of outcomes with independent variables. Among all-births, we then compared risk ratios from three analytic strategies: with standard inference that assumes independently sampled births to the same mother in the model, with cluster-robust inference, and adjusting for parity.We observed minor differences in the population characteristics between the all-birth (N=2,736,693), random-selection, and first-observed birth cohorts (both N=2,284,660), with more substantial differences between these cohorts and the primiparous-births cohort (N=1,054,684). Outcome prevalence was consistently lowest among all-births and highest among primiparous-births (e.g., severe maternal morbidity 18.9 per 1,000 births among primiparous-births vs. 16.6 per 1,000 births among all-births). When stratified by parity, outcome prevalence was always the lowest in births of parity 2 and highest among births of parity 1 for both outcomes. Risk ratios differed for study outcomes across all four cohorts, with the most pronounced differences between the primiparous-birth cohort and other cohorts. Among all-births, robust inference minimally impacted the confidence bounds of estimates, compared to the standard inference, i.e., crude estimates (e.g., lupus-severe maternal morbidity association: 4.01, 95% CI 3.54-4.55 vs. 4.01, 95% CI 3.53-4.56 for crude estimate), while adjusting for parity slightly shifted estimates, towards the null for severe maternal morbidity and away from the null for preeclampsia/eclampsia.Researchers should consider the alignment between the methods they use, their sampling strategy, and their research question. This could include refining the research question to better match inference possible for available data, considering alternative data sources, and appropriately noting data limitations and resulting bias, as well as the generalizability of findings. If parity is an established effect modifier, stratified results should be presented.

    View details for DOI 10.1016/j.ajogmf.2024.101434

    View details for PubMedID 38996915

  • Exome sequencing identifies novel genes underlying primary congenital glaucoma in the National Birth Defects Prevention Study. Birth defects research Blue, E. E., Moore, K. J., North, K. E., Desrosiers, T. A., Carmichael, S. L., White, J. J., Chong, J. X., Bamshad, M. J., Jenkins, M. M., Almli, L. M., Brody, L. C., Freedman, S. F., Reefhuis, J., Romitti, P. A., Shaw, G. M., Werler, M., Kay, D. M., Browne, M. L., Feldkamp, M. L., Finnell, R. H., Nembhard, W. N., Pangilinan, F., Olshan, A. F. 2024; 116 (7): e2384

    Abstract

    Primary congenital glaucoma (PCG) affects approximately 1 in 10,000 live born infants in the United States (U.S.). PCG has a autosomal recessive inheritance pattern, and variable expressivity and reduced penetrance have been reported. Likely causal variants in the most commonly mutated gene, CYP1B1, are less prevalent in the U.S., suggesting that alternative genes may contribute to the condition. This study utilized exome sequencing to investigate the genetic architecture of PCG in the U.S. and to identify novel genes and variants.We studied 37 family trios where infants had PCG and were part of the National Birth Defects Prevention Study (births 1997-2011), a U.S. multicenter study of birth defects. Samples underwent exome sequencing and sequence reads were aligned to the human reference sample (NCBI build 37/hg19). Variant filtration was conducted under de novo and Mendelian inheritance models using GEMINI.Among candidate variants, CYP1B1 was most represented (five trios, 13.5%). Twelve probands (32%) had potentially pathogenic variants in other genes not previously linked to PCG but important in eye development and/or to underlie Mendelian conditions with potential phenotypic overlap (e.g., CRYBB2, RXRA, GLI2).Variation in the genes identified in this population-based study may help to further explain the genetics of PCG.

    View details for DOI 10.1002/bdr2.2384

    View details for PubMedID 38990107

    View details for PubMedCentralID PMC11245170

  • Socioeconomic disadvantage and racial/ethnic disparities in low-risk cesarean birth in California. American journal of epidemiology Bane, S., Mujahid, M. S., Main, E. K., Carmichael, S. L. 2024

    Abstract

    Our objective was to assess the relationship of socioeconomic disadvantage and race/ethnicity with low-risk cesarean birth. We examined birth certificates (2007-18) linked with maternal hospitalization data from California; the outcome was cesarean birth among low-risk deliveries (i.e., nulliparous, term, singleton, vertex [NTSV]). We used GEE Poisson regression with an interaction term for race/ethnicity (7 groups) and a measure of socioeconomic disadvantage (census tract-level neighborhood deprivation index [NDI], education, or insurance). Among 1,815,933 NTSV births, 26.6% were cesarean. When assessing the joint effect of race/ethnicity and socioeconomic disadvantage among low-risk births, risk of cesarean birth increased with socioeconomic disadvantage for most racial/ethnic groups, and disadvantaged Black individuals had the highest risks; e.g., Black individuals with a high school education or less had a risk ratio of 1.49 (95% CI 1.45-1.53), relative to White individuals with a college degree. The disparity in risk of cesarean birth between Black and White individuals was observed across all strata of socioeconomic disadvantage. Asian American and Hispanic individuals had higher risks than White individuals at lower socioeconomic disadvantage; this disparity was not observed at higher levels of disadvantage. Black individuals have a persistent, elevated risk of cesarean birth, relative to White individuals, regardless of socioeconomic disadvantage.

    View details for DOI 10.1093/aje/kwae157

    View details for PubMedID 38932570

  • Neighborhood-level Fatal Police Violence and Severe Maternal Morbidity in California. American journal of epidemiology Hailu, E. M., Riddell, C. A., Tucker, C., Ahern, J., Bradshaw, P. T., Carmichael, S. L., Mujahid, M. S. 2024

    Abstract

    Police violence is a pervasive issue that may have adverse implications for severe maternal morbidity (SMM). We assessed how the occurrence of fatal police violence (FPV) in one's neighborhood before/during pregnancy may influence SMM risk. Hospital discharge records from California between 2002-2018 were linked with the Fatal Encounters database (N=2,608,682). We identified 2,184 neighborhoods (census-tracts) with at least one FPV incident during the study period and used neighborhood fixed-effects models adjusting for individual sociodemographic characteristics to estimate odds of SMM associated with experiencing FPV in one's neighborhood anytime within the 24-months before childbirth. We did not find conclusive evidence on the link between FPV occurrence before delivery and SMM. However, estimates show that birthing people residing in neighborhoods where one or more FPV events had occurred within the preceding 24-months of giving birth may have a mildly elevated odds of SMM than those residing in the same neighborhoods with no FPV occurrence during the 24-months preceding childbirth (Odds Ratio (OR)=1.02; 95% Confidence Interval (CI): 0.99-1.05), particularly among those living in neighborhoods with fewer (1-2) FPV incidents throughout the study period (OR=1.03; 95% CI:1.00-1.06). Our findings provide evidence for the need to continue to examine the health consequences of police violence.

    View details for DOI 10.1093/aje/kwae124

    View details for PubMedID 38879741

  • Epidemiology of elective induction of labour: a timeless exposure. International journal of epidemiology Snowden, J. M., Bane, S., Osmundson, S. S., Odden, M. C., Carmichael, S. L. 2024; 53 (4)

    View details for DOI 10.1093/ije/dyae088

    View details for PubMedID 38964853