A pilot autism case-control study of pesticides and plasticizers in shed baby teeth.

Abstract

Even moderate exposures to pesticides and plasticizers have been associated with neurotoxicity and autism characteristics; however, most studies of urine and blood provide a short-term exposure window compared to teeth, which capture long-term exposures from 13-14 weeks in-utero through early childhood. We investigated cumulative pesticide and plasticizer exposures in shed baby teeth from children with and without autism using a comprehensive targeted and non-targeted analysis with two-dimensional gas chromatography coupled with time-of-flight mass spectrometry (GCxGC-TOFMS). Compound identification was confirmed with standards and high-fidelity spectral library matches. Sixty compounds were detected in more than 50% of participants (n = 38). Of these, 95% (57/60) were higher in cases compared to controls, and 19/60 were statistically significantly elevated. Thirty-nine of the 60 compounds detected are known developmental toxicants or endocrine-disrupting compounds. To date, 21/60 compounds lack Environmental Protection Agency (EPA) developmental toxicity data. Compounds exhibiting higher levels in cases than in controls include benzyl benzoate (fragrance and food preservative) and organophosphate esters, which are frequently found in flame retardants and other baby products, PEX tubing, food contact materials, and products applied to the skin. Interestingly, five of the top nine compounds that differentiated cases from controls migrate from baby bottles. Elevated levels of toxicants in autism cases in our pilot study highlight a need for larger case-control studies to understand the effects of long-term exposure on autism.