Mixture of air pollution, brominated flame retardants, polychlorinated biphenyls, per- and polyfluoroalkyl substances, and organochlorine pesticides in relation to vitamin D concentrations in pregnancy.

Over two-thirds of pregnant women in the U.S. have insufficient 25(OH)D (Vitamin D) concentrations, which can adversely impact fetal health. Several pollutants have been associated with 25(OH)D, but have not been considered in the context of chemical co-exposures. We aimed to determine associations between a broad mixture of prenatal environmental chemical exposures and 25(OH)D concentrations in mid-pregnancy. Stored mid-pregnancy serum samples were assayed from 421 women delivering live births in Southern California in 2000-2003. 25(OH)D, six BFRs, eleven polychlorinated biphenyls (PCBs), six per- and polyfluoroalkyl substances, and two organochlorine pesticides were detected in ≥60% of specimens. Gestational exposures to airborne particulate matter ≤ 10 µm (PM10) and ≤ 2.5 µm (PM2.5), nitrogen monoxide (NO), nitrogen dioxide (NO2), and ozone concentrations were derived from monitoring station data. Bayesian Hierarchical Modeling (BHM) and Bayesian Kernel Machine Regression (BKMR) analyses estimated overall mixture and individual chemical associations accounting for co-exposures and covariates with mean 25(OH)D levels, and BHM was used to estimate associations with insufficient (<75 nMol/L) 25(OH)D levels. Non-mixture associations for each chemical were estimated with linear and logistic models. PM10 [BHM estimate: -0.133 nmol/l 95% Credible Interval (-0.240, -0.026)] was associated with lower 25(OH)D in BHM and BKMR. Higher quantiles of combined exposures were associated with lower 25(OH)D, though with wide credible intervals. In non-mixture models, PM10, PM2.5, NO, and NO2 were associated with lower concentrations, while O3 and PBDE153 were associated with higher 25(OH)D and/or lower insufficiency. While some chemicals were associated with increased and others with decreased 25(OH)D concentrations, the overall mixture was associated with lower concentrations. Mixture analyses differed from non-mixture regressions, highlighting the importance of mixtures approaches for estimating real-world associations.

The association of in utero tobacco smoke exposure, quantified by serum cotinine, and Autism Spectrum Disorder.

Previous studies on in utero exposure to maternal environmental tobacco smoke (ETS) or maternal active smoking and Autism Spectrum Disorder (ASD) have not been entirely consistent, and no studies have examined in utero cotinine concentrations as an exposure classification method. We measured cotinine in stored second trimester maternal serum for 498 ASD cases and 499 controls born in California in 2011-2012. We also obtained self-reported maternal cigarette smoking during and immediately prior to pregnancy, as well as covariate data, from birth records. Using unconditional logistic regression, we found no association between log10 cotinine concentrations and odds for developing ASD among children of non-smokers (aOR: 0.93 [95% CI: 0.69, 1.25] per ng/ml), which represents exposure to ETS, though there may be a possible interaction with race. We found no association between cotinine-defined smoking (≥3.08 ng/ml vs. <3.08 ng/ml) (adjusted odds ratio [aOR]: 0.73 (95% confidence interval [95% CI]: 0.35, 1.54)) or self-reported smoking (aOR: 1.64 [95% CI: 0.65, 4.16]) and ASD. In one of the few studies of ETS and the first with measured cotinine, our results indicate no overall relationship between in utero exposure to tobacco smoke from maternal ETS exposure or active smoking, and development of ASD. LAY SUMMARY: This study found that women who smoke or are exposed to tobacco smoke during pregnancy are not more likely to have children with Autism Spectrum Disorder (ASD). This is the first ASD study to measure a chemical in the mother's blood during pregnancy to identify exposure to tobacco smoke.

Independent Maternal and Fetal Genetic Effects on Midgestational Circulating Levels of Environmental Pollutants.

Maternal exposure to environmental pollutants could affect fetal brain development and increase autism spectrum disorder (ASD) risk in conjunction with differential genetic susceptibility. Organohalogen congeners measured in maternal midpregnancy blood samples have recently shown significant, but negative associations with offspring ASD outcome. We report the first large-scale maternal and fetal genetic study of the midpregnancy serum levels of a set of 21 organohalogens in a subset of 790 genotyped women and 764 children collected in California by the Early Markers for Autism (EMA) Project. Levels of PCB (polychlorinated biphenyl) and PBDE (polybrominated diphenyl ether) congeners showed high maternal and fetal estimated SNP-based heritability (h2g ) accounting for 39-99% of the total variance. Genome-wide association analyses identified significant maternal loci for p,p'-DDE (P = 7.8 × 10-11) in the CYP2B6 gene and for BDE-28 (P = 3.2 × 10-8) near the SH3GL2 gene, both involved in xenobiotic and lipid metabolism. Fetal genetic loci contributed to the levels of BDE-100 (P = 4.6 × 10-8) and PCB187 (P = 2.8 × 10-8), near the potential metabolic genes LOXHD1 and PTPRD, previously implicated in neurodevelopment. Negative associations were observed for BDE-100, BDE153, and the sum of PBDEs with ASD, partly explained by genome-wide additive genetic effects that predicted PBDE levels. Our results support genetic control of midgestational biomarkers for environmental exposures by nonoverlapping maternal and fetal genetic determinants, suggesting that future studies of environmental risk factors should take genetic variation into consideration. The independent influence of fetal genetics supports previous hypotheses that fetal genotypes expressed in placenta can influence maternal physiology and the transplacental transfer of organohalogens.

Neonatal cytokines and chemokines and risk of Autism Spectrum Disorder: the Early Markers for Autism (EMA) study: a case-control study.

BACKGROUND: Biologic markers of infection and inflammation have been associated with Autism Spectrum Disorders (ASD) but prior studies have largely relied on specimens taken after clinical diagnosis. Research on potential biologic markers early in neurodevelopment is required to evaluate possible causal pathways and screening profiles. OBJECTIVE: To investigate levels of cytokines and chemokines in newborn blood specimens as possible early biologic markers for autism. METHODS: We conducted a population-based case-control study nested within the cohort of infants born from July 2000 to September 2001 to women who participated in the prenatal screening program in Orange County, California, USA. The study population included children ascertained from the California Department of Developmental Services with Autism Spectrum Disorder (ASD, n = 84), or developmental delay but not ASD (DD, n = 49), and general population controls randomly sampled from the birth certificate files and frequency matched to ASD cases on sex, birth month and birth year (GP, n = 159). Cytokine and chemokine concentrations were measured in archived neonatal blood specimens collected for routine newborn screening. RESULTS: Cytokines were not detected in the vast majority of newborn samples regardless of case or control status. However, the chemokine monocyte chemotactic protein-1 (MCP-1) was elevated and the chemokine Regulated upon Activation Normal T-Cell Expressed and Secreted (RANTES) was decreased in ASD cases compared to GP controls. The chemokines macrophage inflammatory protein-1alpha (MIP-1α) and RANTES were decreased in children with DD compared to GP controls. CONCLUSION: Measurement of immune system function in the first few days of life may aid in the early identification of abnormal neurodevelopment and shed light on the biologic mechanisms underlying normal neurodevelopment.