Styrene exposure and neurologic effects in residents of the US Gulf States

Styrene is an established neurotoxicant at occupational levels, but epidemiologic studies to date have focused on highly exposed workers. We examine whether neurologic effects are associated with styrene at environmental levels, and attempt to identify underlying sources of uniquely elevated exposure levels among Gulf coast residents. In Aims 1 and 2, we utilized data from the Gulf Long-term Follow-up Study and the nested Chemical Biomonitoring Study (CBS) to assess predictors of blood styrene levels (N = 667). In Aim 3, we estimated cross-sectional associations between ambient styrene exposure and neurologic symptoms (N = 21,962), as well as peripheral neurologic function (N = 2,956). Among CBS participants, we assessed blood styrene in relation to neurologic symptoms (N = 874) and peripheral neurologic function (N = 310). Ambient exposures were modeled as quartiles, and blood exposures were divided at the median or 90th percentile. We estimated prevalence ratios using log-binomial regression, and differences in continuous outcomes using linear regression. Blood styrene levels are 2-3 times higher in CBS compared to the U.S. general population. Smoking, housing characteristics, and recent behaviors were predictors of blood styrene levels. Neither ambient styrene concentrations nor industrial styrene emissions were determinants of blood styrene levels. The highest quartile of ambient styrene was associated with increased central (PR = 1.20, 95% CI: 1.09, 1.32) and peripheral (PR = 1.12, 95% CI: 1.02, 1.23) nervous system symptoms, as well as impairments in vision (mean difference = -0.15, 95% CI: -0.25, -0.04), vestibular (β = -4.65 mm/s, 95% CI: -8.20, -1.10), and sensory function (β = -0.12 log microns, 95% CI: -0.22, -0.01). We observed statistically significant monotonic exposure-response relationships between ambient styrene concentration and many neurologic endpoints. The relationship was less clear for blood styrene exposure, with some suggestive effects. Personal predictors of increasing blood styrene levels were largely consistent with previous literature. Our measures of increased regional exposure opportunity do not fully explain these elevated blood styrene levels. Increasing ambient styrene exposures elicited consistent neurotoxic effects, as well as some notable associations with measured blood styrene. Environmental styrene exposure levels may be sufficient to elicit subclinical neurotoxic effects.Doctor of Philosoph

Maternal psychiatric disorders and risk of preterm birth

To study the effect of maternal psychiatric disorders (depression, anxiety disorder, bipolar disease, schizophrenia, unspecified psychiatric disorder, and comorbid conditions) and odds of preterm birth

Effect of maternal chronic disease on obstetric complications in twin pregnancies in a United States cohort

To evaluate the effect of maternal chronic disease on obstetric complications among twin pregnancies

Fine particulate matter and incident coronary heart disease events up to 10 years of follow-up among Deepwater Horizon oil spill workers.

BACKGROUND: During the 2010 Deepwater Horizon (DWH) disaster, in-situ burning and flaring were conducted to remove oil from the water. Workers near combustion sites were potentially exposed to burning-related fine particulate matter (PM2.5). Exposure to PM2.5 has been linked to increased risk of coronary heart disease (CHD), but no study has examined the relationship among oil spill workers. OBJECTIVES: To investigate the association between estimated PM2.5 from burning/flaring of oil/gas and CHD risk among the DWH oil spill workers. METHODS: We included workers who participated in response and cleanup activities on the water during the DWH disaster (N = 9091). PM2.5 exposures were estimated using a job-exposure matrix that linked modelled PM2.5 concentrations to detailed DWH spill work histories provided by participants. We ascertained CHD events as the first self-reported physician-diagnosed CHD or a fatal CHD event that occurred after each workers last day of burning exposure. We estimated hazard ratios (HR) and 95% confidence intervals (95%CI) for the associations between categories of average or cumulative daily maximum PM2.5 exposure (versus a referent category of water workers not near controlled burning) and subsequent CHD. We assessed exposure-response trends by examining continuous exposure parameters in models. RESULTS: We observed increased CHD hazard among workers with higher levels of average daily maximum exposure (low vs. referent: HR = 1.26, 95% CI: 0.93, 1.70; high vs. referent: HR = 2.11, 95% CI: 1.08, 4.12; per 10 μg/m3 increase: HR = 1.10, 95% CI: 1.02, 1.19). We also observed suggestively elevated HRs among workers with higher cumulative daily maximum exposure (low vs. referent: HR = 1.19, 95% CI: 0.68, 2.08; medium vs. referent: HR = 1.38, 95% CI: 0.88, 2.16; high vs. referent: HR = 1.44, 95% CI: 0.96, 2.14; per 100 μg/m3-d increase: HR = 1.03, 95% CI: 1.00, 1.05). CONCLUSIONS: Among oil spill workers, exposure to PM2.5 from flaring/burning of oil/gas was associated with increased risk of CHD

Maternal psychiatric disorders and risk of preterm birth

PURPOSE: To study the effect of maternal psychiatric disorders (depression, anxiety disorder, bipolar disease, schizophrenia, unspecified psychiatric disorder, and comorbid conditions) and odds of preterm birth. METHODS: The Consortium on Safe Labor (2002-2008), an observational cohort with 12 centers from across the U.S. included 223,394 singleton pregnancies with clinical data obtained from electronic medical records and maternal diagnoses of psychiatric disorders from maternal discharge summaries. Length of gestation was based on the best clinical estimate and categorized as birth <39, <37, <34 and <28 weeks’ gestation. The adjusted odds ratios (ORs) with 95% confidence intervals of birth were estimated by logistic regression with generalized estimating equations. RESULTS: Any maternal psychiatric disorder was associated with odds of birth <39 weeks’ gestation (OR=1.32, 95% confidence interval 1.28-1.37), <37 weeks’ gestation (OR=1.45, 1.38-1.52), <34 weeks’ gestation (OR=1.47, 1.35-1.59) and <28 weeks’ gestation (OR=1.57, 1.36-1.82). Specifically, odds of birth <37 weeks’ gestation were associated with maternal depression (OR=1.31, 1.23-1.40), anxiety disorder (OR=1.68, 1.41-2.01), depression with anxiety disorder (OR=2.31, 1.93-2.78), bipolar disease (OR=1.54, 1.22-1.94), bipolar disease with depression and=or anxiety disorder (OR=1.70, 1.30-2.22) and unspecified psychiatric disorder (OR=1.52, 1.41-1.64). CONCLUSIONS: Maternal psychiatric disorders, especially comorbid psychiatric conditions, were associated with increased likelihood of preterm birth

Effect of maternal chronic disease on obstetric complications in twin pregnancies in a United States cohort

To evaluate the effect of maternal chronic disease on obstetric complications among twin pregnancies