Gestational endocrine disrupting chemical exposure and autistic behaviors in 4 to 5 year old children from Cincinnati OH

Abstract

Background: Endocrine disrupting chemicals (EDCs) may increase the risk of autism, possibly by perturbing fetal hormone signaling or metabolism, but this complex exposure mixture makes identifying the most relevant EDCs difficult. Aims: To identify gestational EDC exposures associated with autistic behaviors. Methods: We measured the concentrations of 52 EDCs including 8 phthalate metabolites, bisphenol A (BPA), 25 polychlorinated biphenyls (PCBs), 6 organochlorine pesticides, 8 brominated flame retardants, and 4 perfluorinated chemicals in blood or urine samples from 175 pregnant women from the HOME Study (Cincinnati, OH). When children were 4 and 5 years old, mothers completed the Social Responsiveness Scale (SRS), a valid/reliable measure of autistic behaviors including interpersonal behavior/communication deficits and repetitive/stereotypic behaviors (mean:50, SD:10). We estimated the association between SRS scores with increasing EDC concentrations using a 2-stage semi-Bayesian hierarchical analysis to adjust for sociodemographic, perinatal, and maternal factors, as well as co-pollutant confounding. Results: The absolute difference in SRS scores associated with most EDCs was negligible (~1 point). Notable exceptions included better SRS scores among children born to women with detectable vs. non-detectable serum PCB-178 (beta:-3.3; 95% confidence interval [CI]:-6.5, -0.1) or b-hexachlorocyclohexane (beta-HCH) concentrations (beta:-3.0; CI:-5.8, -0.2), and increasing serum perfluoroctane (PFOA) concentrations (beta:-1.9; CI:-4.3, 0.5). Higher serum polybrominated diphenyl ether-28 (PBDE-28; beta:2.5; CI:-0.6, 5.6) and trans-nonachlor (beta:4.0; CI:0.7, 7.2) concentrations were associated with worse SRS scores. Conclusion:Although our modest sample size precludes us from dismissing chemicals as risk factors for autistic-like behaviors, we conclude that beta-HCH, PCB-178, PBDE-28, PFOA, and trans-nonachlor deserve additional scrutiny as factors that may increase or decrease the risk of autism in children.