Abstract:

BACKGROUND: Maternal folic acid (FA) protects against developmental toxicity from certain environmental chemicals.

OBJECTIVE: We examined combined exposures to maternal FA and pesticides in relation to autism spectrum disorder (ASD).

METHODS: Participants were California children born from 2000–2007 who were enrolled in the Childhood Autism Risks from Genetics and the Environment (CHARGE) case–control study at age 2–5 y, were clinically confirmed to have ASD (n= 296) or typical development (n= 220), and had information on maternal supplemental FA and pesticide exposures. Maternal supplemental FA and household pesticide product use were retrospectively collected in telephone interviews from 2003–2011. High vs. low daily FA intake was dichotomized at 800 lg (median). Mothers’ addresses were linked to a statewide database of commercial applications to estimate agricultural pesticide exposure.

RESULTS: High FA intake (≥800 lg) during the first pregnancy month and no known pesticide exposure was the reference group for all analyses. Compared with this group, ASD was increased in association with
CONCLUSIONS: In this study population, associations between pesticide exposures and ASD were attenuated among those with high versus low FA intake during the first month of pregnancy. Confirmatory and mechanistic studies are needed. ht

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