Maternal Air Pollutant Exposure Around Pregnancy and Risk of Autism Spectrum Disorder

Saturday, 15 February 2014
Crystal Ballroom A (Hyatt Regency Chicago)
Marc Weisskopf , Environmental Health, Harvard University, Boston, MA
Air pollution contains many toxicants known to affect neurological function and to have effects on the fetus in utero. Research into the association between in utero and early life exposure to air pollutants and risk of autism spectrum disorder (ASD) is limited, but a few studies have suggested an increased risk for ASD with higher exposure to air pollutants. We explored this among children of mothers in the Nurses’ Health Study 2, a U.S. wide cohort of medically trained women. We first used U.S. Environmental Protection Agency modeled levels of hazardous air pollutants (HAPs) to estimate exposures in the mother’s census tract during the year of the child’s birth.  Second, we used our validated and much higher resolution spatiotemporal model of particulate matter (PM) exposure that incorporates information from monitoring networks, meteorology, and a collection of geographic information system-based predictors to estimate maternal PM exposure at her residence before, during, and after the specific months of pregnancy.  We found significantly elevated risk for autism spectrum disorders with higher exposure to several HAPs, including several metals, methylene chloride, and diesel particulate matter.  In analyses of the more highly spatially and temporally resolved PM exposure data, we found significantly increased risk of ASD associated with PM2.5 (PM <2.5µm in diameter) exposure during the specific months of pregnancy.  There were weaker associations with PM10 (PM <10µm in diameter).  Associations with PM2.5 exposure 9 months before or after the pregnancy were substantially lower.  These data provide strong support for the involvement of aspects of air pollution in the development of ASD.  The accumulating evidence for such an association raises the possibility of interventions to reduce the burden of ASD and suggests that efforts to understand the biological pathways by which air pollutants may affect brain development are warranted.