Suspect Screening of Urinary Neurotoxicants in Children with Autistic Spectrum Disorder

Environmental exposure to toxic chemicals has long been suspected an important factor contributing to autism spectrum disorder (ASD) in children. Our study developed a suspect screening strategy to broaden the understanding of neurotoxicant exposure in children with ASD (n = 307) and healthy controls (n = 461) and the association between ASD and mixed chemical exposure. Suspect screening of urine samples from the study population identified a total of 94 neurotoxicants designated as confidence level 1, with additional 16 and 34 compounds designated as confidence level 2 and 3, respectively. Among identified level 1 compounds, 48 had a detection frequency >70% in the study population, covering plasticizers, polycyclic aromatic hydrocarbons, insecticides, flame retardants, ultraviolet filters, antimicrobial agents and synthetic antioxidants. The results reveal a complexity of exposure spectrum in ASD children. Conditional logistic regression analyses with level 1 compounds revealed significant associations between ASD and increasing urinary levels of 28 neurotoxicants. Mixed exposure analysis revealed a strong association between combined neurotoxicant exposure and the ASD diagnosis. Among the diversity of neurotoxicants, 1,3-diphenylguanidine (DPG), diphenyl phosphate (DPP) and mono (2-ethyl-5-carboxypentyl) phthalate (mECPP) were identified as the key substances contributing to the exposure-ASD associations. Collectively, our work reported a complex neurotoxicant exposure spectrum in ASD children and associations between neurotoxicant exposure and ASD. The findings highlight the complexity of neurotoxicant exposure in children and the importance of exploring environmental factors of ASD.