Maeve Wallace

Allostatic load and birth outcomes among white and black women in New Orleans

As a marker of chronic stress, allostatic load has been theoretically recognized as a potential contributor to racial disparities in birth outcomes. The purpose of this investigation was to identify associations between allostatic load and birth outcomes and to assess differences in allostatic load and its relation to birth outcomes between white and black women. Blood samples from 123 women at 26–28xa0weeks gestation were assayed for cholesterol, glycosylated hemoglobin, dehydroepiandrosterone-sulfate, and cortisol, with 42 women having complete data on all biomarkers and birth outcomes. Together with systolic blood pressure, these biomarkers were combined to create an allostatic load index. Multiple linear regression models were used to evaluate associations between allostatic load index and gestational age, birth weight, birth weight ratio, birth length, and head circumference. Black women had a significantly lower allostatic load index than white women (Pxa0<xa00.05). Gestational age was the only outcome significantly associated with allostatic load in both unadjusted and adjusted models (Pxa0<xa00.05). Gestational age decreased significantly with increasing allostatic load (adjusted β −0.18, 95xa0% CI −0.35, 0.00). A significant interaction with age indicated that the effect was less strong at higher maternal ages (adjusted interaction β 0.04, 95xa0% CI 0.00, 0.08). There was no racial difference in the effect of allostatic load on birth outcomes. These findings represent possible evidence of the effect of stress age on gestational age. As a measure of cumulative disadvantage, allostatic load may prove to be a contributor to the racial disparities in birth outcomes.

Neighborhood poverty, allostatic load, and birth outcomes in African American and white women: findings from the Bogalusa Heart Study.

As a biologically-mediated pathway between adversity and declines in physical health, allostatic load has been frequently hypothesized as a potential contributor to racial disparities in birth outcomes, but an empirical evidence is lacking. The purpose of this study was to examine the relationships between maternal preconception allostatic load, race, and adverse birth outcomes within the context of neighborhood-level poverty using data from the Bogalusa Heart Study. Allostatic load was quantified as a count of regulatory biomarkers falling in the highest risk quartile of the sample distribution as measured from a physical examination that took place prior to conception. Consistent with previous findings, African American women resided in more impoverished neighborhoods and had higher allostatic load scores compared to whites; however, allostatic load was not associated with preterm birth or low birth weight in fully adjusted models. These results underscore a need for further refinement of both biologic and contextual measures that capture holistically the way in which stressful conditions and experiences encountered across the life-course influence health potentials and engender inequities in reproductive health outcomes.

Obstetric and Neonatal Risks Among Obese Women Without Chronic Disease.

OBJECTIVE: To investigate whether prepregnancy obesity is associated with adverse pregnancy outcomes among women without chronic disease. METHODS: Singleton deliveries (N=112,309) among mothers without chronic diseases in the Consortium on Safe Labor, a retrospective U.S. cohort, were analyzed using Poisson regression with robust variance estimation. Relative risks and 95% confidence intervals (CIs) estimated perinatal risks in relation to prepregnancy obesity status adjusted for age, race–ethnicity, parity, insurance, smoking and alcohol use during pregnancy, and study site. RESULTS: Obstetric risks were variably (and mostly marginally) increased as body mass index (BMI) category and obesity class increased. In particular, the risk of gestational hypertensive disorders, gestational diabetes, cesarean delivery, and induction increased in a dose–response fashion. For example, the percentage of gestational diabetes among obese class III women was 14.6% in contrast to 2.8% among women with normal BMIs (corresponding relative risks [95% CI] 1.99 [1.86–2.13], 2.94 [2.73–3.18], 3.97 [3.61–4.36], and 5.47 [4.96–6.04] for overweight, obese class I, obese class II, and obese class III women, respectively) compared with women with normal BMIs. Similarly, neonatal risks increased in a dose–response fashion with maternal BMI status including preterm birth at less than 32 weeks of gestation, large for gestational age (LGA), transient tachypnea, sepsis, and intensive care unit admission. The percentage of LGA neonates increased from 7.9% among women with normal BMIs to 17.3% among obese class III women and relative risks increased to 1.52 (1.45–1.58), 1.74 (1.65–1.83), 1.93 (1.79–2.07), and 2.32 (2.14–2.52) as BMI category increased. CONCLUSION: Prepregnancy obesity is associated with increased risks of a wide range of adverse pregnancy and neonatal outcomes among women without chronic diseases.

Association Between Neighborhood Violence and Biological Stress in Children

Importance Exposure to violence continues to be a growing epidemic, particularly among children. An enhanced understanding of the biological effect of exposure to violence is critical. Objective To examine the association between neighborhood violence and cellular and biological stress in children. Design, Setting, and Participants A matched, cross-sectional study of 85 black children aged 5 to 16 years from 52 neighborhoods took place in the greater New Orleans, Louisiana, area between January 1, 2012, and July 31, 2013. Exposures Density of businesses where individuals can purchase alcohol as measured by rates per capita of liquor or convenience stores, and violence as measured by reports of violent crime and reports of domestic violence, operationalized as reports per capita of crime and domestic violence. Rates of exposure within a 500-, 1000-, and 2000-m radius from the child’s home were calculated. Main Outcomes and Measures Primary biological outcomes were telomere length and cortisol functioning. Results Among the 85 children in the study, (mean [SD] age, 9.8 [3.1] years; 50 girls and 35 boys) significant variation in telomere length and cortisol functioning was observed at the neighborhood level, with intraclass correlation coefficients of 6% for telomere length, 3.4% for waking cortisol levels, and 5.5% for peak cortisol levels following a stressor. Density of liquor or convenience stores within a 500-m radius of a child’s home was associated with a decrease in mean telomere length by 0.004 for each additional liquor store or convenience store (&bgr; [SE], –0.004 [0.002]; Pu2009=u2009.02). The rate of domestic violence was significantly and inversely associated with a decrease in mean telomere length by 0.007 for each additional report of domestic violence in a 500-m radius of a child’s home (&bgr; [SE], –0.007 [0.001]; Pu2009<u2009.001). The rate of violent crime was significantly associated with a decrease in mean telomere length by 0.006 for each additional report of violent crime in a 500-m radius of a child’s home (&bgr; [SE], –0.006 [0.002]; Pu2009<u2009.001). Children exposed to more liquor and convenience stores within 500 m of their home were significantly less likely to reduce cortisol levels after a reactivity test (&bgr;, 0.029; Pu2009=u2009.047), as were children exposed to high rates of domestic violence (&bgr;, 0.088; Pu2009=u2009.12) and violent crime (&bgr;, 0.029; Pu2009=u2009.006). Children exposed to more liquor and convenience stores within 500 m of their home had a steeper diurnal decline in cortisol levels during the day (&bgr; [SE], –0.002 [0.001]; Pu2009=u2009.04), as did children exposed to more violent crime within 500 m of their home (&bgr; [SE] –0.032 [0.014]; Pu2009=u2009.02). Conclusions and Relevance Neighborhoods are important targets for interventions to reduce the effect of exposure to violence in the lives of children. These findings provide the first evidence that objective exposures to neighborhood-level violence influence both physiological and cellular markers of stress, even in children.

Joint Effects of Structural Racism and Income Inequality on Small-for-Gestational-Age Birth

OBJECTIVESnWe examined potential synergistic effects of racial and socioeconomic inequality associated with small-for-gestational-age (SGA) birth.nnnMETHODSnElectronic medical records from singleton births to White and Black women in 10 US states and the District of Columbia (nu2009=u2009121u2009758) were linked to state-level indicators of structural racism, including the ratios of Blacks to Whites who were employed, were incarcerated, and had a bachelors or higher degree. We used state-level Gini coefficients to assess income inequality. Generalized estimating equations models were used to quantify the adjusted odds of SGA birth associated with each indicator and the joint effects of structural racism and income inequality.nnnRESULTSnStructural racism indicators were associated with higher odds of SGA birth, and similar effects were observed for both races. The joint effects of racial and income inequality were significantly associated with SGA birth only when levels of both were high; in areas with high inequality levels, adjusted odds ratios ranged from 1.81 to 2.11 for the 3 structural racism indicators.nnnCONCLUSIONSnHigh levels of racial inequality and socioeconomic inequality appear to increase the risk of SGA birth, particularly when they co-occur.

Racial/ethnic differences in preterm perinatal outcomes.

Background: Racial disparities in preterm birth and infant death have been well documented. Less is known about racial disparities in neonatal morbidities among infants who are born at <37 weeks of gestation. Objective: The purpose of this study was to determine whether the risk for morbidity and death among infants who are born preterm differs by maternal race. Study Design: A retrospective cohort design included medical records from preterm deliveries of 19,325 black, Hispanic, and white women in the Consortium on Safe Labor. Sequentially adjusted Poisson models with generalized estimating equations estimated racial differences in the risk for neonatal morbidities and death, controlling for maternal demographics, health behaviors, and medical history. Sex differences between and within race were examined. Results: Black preterm infants had an elevated risk for perinatal death, but there was no difference in risk for neonatal death across racial groups. Relative to white infants, black infants were significantly more likely to experience sepsis (9.1% vs 13.6%), peri‐ or intraventricular hemorrhage (2.6% vs 3.3%), intracranial hemorrhage (0.6% vs 1.8%), and retinopathy of prematurity (1.0% vs 2.6%). Hispanic and white preterm neonates had similar risk profiles. In general, female infants had lower risk relative to male infants, with white female infants having the lowest prevalence of a composite indicator of perinatal death or any morbidity across all races (30.9%). Differences in maternal demographics, health behaviors, and medical history did little to influence these associations, which were robust to sensitivity analyses of pregnancy complications as potential underlying mechanisms. Conclusion: Preterm infants were at similar risk for neonatal death, regardless of race; however, there were notable racial disparities and sex differences in rare, but serious, adverse neonatal morbidities.

Preterm birth and air pollution: Critical windows of exposure for women with asthma

BACKGROUNDnAmbient air pollutants may increase preterm birth (PTB) risk, but critical exposure windows are uncertain. The interaction of asthma and pollutant exposure is rarely studied.nnnOBJECTIVEnWe sought to assess the interaction of maternal asthma and air pollutant exposures in relation to PTB risk.nnnMETHODSnElectronic medical records for 223,502 US deliveries were linked with modified Community Multiscale Air Quality model outputs. Logistic regression with generalized estimating equations estimated the odds ratio and 95% CIs for PTB on the basis of the interaction of maternal asthma and particulate matter with aerodynamic diameter of less than 2.5 microns and particulate matter with aerodynamic diameter of less than 10 microns, ozone (O3), nitrogen oxides (NOx), sulfur dioxide (SO2), and carbon monoxide (CO) per interquartile range. For each gestational week 23 to 36, exposures among women who delivered were compared with those remaining pregnant. Three-month preconception, whole pregnancy, weeks 1 to 28, and the last 6xa0weeks of gestation averages were also evaluated.nnnRESULTSnOn assessing PTB by gestational week, we found that significant asthma interactions were sporadic before 30xa0weeks but more common during weeks 34 to 36, with higher risk among mothers with asthma for NOx, CO, and SO2 exposure and an inverse association with O3 in week 34. Odds of PTB were significantly higher among women with asthma for CO and NOx exposure preconception and early in pregnancy. In the last 6xa0weeks of pregnancy, PTB risk associated with particulate matter with aerodynamic diameter of less than 10 microns was higher among women with asthma.nnnCONCLUSIONSnMothers with asthma may experience a higher risk for PTB after exposure to traffic-related pollutants such as CO and NOx, particularly for exposures 3-months preconception and in the early weeks of pregnancy.

Air pollution exposure and preeclampsia among US women with and without asthma

Maternal asthma and air pollutants have been independently associated with preeclampsia but rarely studied together. Our objective was to comprehensively evaluate preeclampsia risk based on the interaction of maternal asthma and air pollutants. Preeclampsia and asthma diagnoses, demographic and clinical data came from electronic medical records for 210,508 singleton deliveries. Modified Community Multiscale Air Quality models estimated preconception, first and second trimester and whole pregnancy exposure to: particulate matter (PM)<2.5 and <10µm, ozone, nitrogen oxides (NOx), sulfur dioxide (SO2) and carbon monoxide (CO); PM2.5 constituents; volatile organic compounds (VOCs) and polycyclic aromatic hydrocarbons (PAHs). Asthma-pollutant interaction adjusted relative risks (RR) and 95% confidence intervals (CI) for preeclampsia were calculated by interquartile range for criteria pollutants and high exposure (≥75th percentile) for PAHs and VOCs. Asthmatics had higher risk associated with first trimester NOx and SO2 and whole pregnancy elemental carbon (EC) exposure than non-asthmatics, but only EC significantly increased risk (RR=1.11, CI:1.03-1.21). Asthmatics also had a 10% increased risk associated with second trimester CO. Significant interactions were observed for nearly all VOCs and asthmatics had higher risk during all time windows for benzene, ethylbenzene, m-xylene, o-xylene, p-xylene and toluene while most PAHs did not increase risk.

Preconception Biomarkers of Allostatic Load and Racial Disparities in Adverse Birth Outcomes: the Bogalusa Heart Study

BACKGROUNDnLarge disparities in adverse birth outcomes persist between African American and white women in the US despite decades of research, policy, and public health intervention. Allostatic load is an index of dysregulation across multiple physiologic systems that results from chronic exposure to stress in the physical and socio-cultural environment which may lead to earlier health deterioration among racially or socio-economically disadvantaged groups. The purpose of this investigation was to examine relationships between maternal biomarkers of allostatic load prior to conception and the occurrence of preterm birth and small for gestational age infants among a cohort of white and African American women participants in the Bogalusa Heart Study.nnnMETHODSnData from women participants were linked to the birth record of their first-born infant. Principal components analysis was used to construct an index of allostatic load as a summary of the weighted contribution of nine biomarkers representing three physiologic domains: cardiovascular, metabolic, and immune systems. A series of Poisson regression models based on samples ranging from 1467 to 375 women were used to examine race, individual biomarkers of allostatic load, and quartiles of the allostatic load index as predictors of preterm birth (n = 150, 10.2%) and small for gestational age (n = 135, 9.2%).nnnRESULTSnThere was no evidence of a relationship between maternal preconception allostatic load and either adverse birth outcome in this sample. Further, there was no evidence of effect modification of by race or education.nnnCONCLUSIONSnMore work is needed in understanding the biological mechanisms linking social inequities to racial disparities in adverse birth outcomes.

Exposure to Ambient Air Pollution and Premature Rupture of Membranes

Premature rupture of membranes (PROM) is a major factor that predisposes women to preterm delivery. Results from previous studies have suggested that there are associations between exposure to air pollution and preterm birth, but evidence of a relationship with PROM is sparse. Modified Community Multiscale Air Quality models were used to estimate mean exposures to particulate matter less than 10 µm or less than 2.5 µm in aerodynamic diameter, nitrogen oxides, carbon monoxide, sulfur dioxide, and ozone among 223,375 singleton deliveries in the Air Quality and Reproductive Health Study (2002-2008). We used log-linear models with generalized estimating equations to estimate adjusted relative risks and 95% confidence intervals for PROM per each interquartile-range increase in pollutants across the whole pregnancy, on the day of delivery, and 5 hours before delivery. Whole-pregnancy exposures to carbon monoxide and sulfur dioxide were associated with an increased risk of PROM (for carbon monoxide, relative risk (RR) = 1.09, 95% confidence interval (CI): 1.04, 1.14; for sulfur dioxide, RR = 1.15, 95% CI: 1.06, 1.25) but not preterm PROM. Ozone exposure increased the risk of PROM on the day of delivery (RR = 1.06, 95% CI: 1.02, 1.09) and 1 day prior (RR = 1.04, 95% CI: 1.01, 1.07). In the 5 hours preceding delivery, there were 3%-7% increases in risk associated with exposure to ozone and particulate matter less than 2.5 µm in aerodynamic diameter and inverse associations with exposure to carbon monoxide and nitrogen oxides. Acute and long-term air pollutant exposures merit further study in relation to PROM.