Prenatal exposure to a mixture of non-persistent endocrine-disrupting chemicals and attention and hyperactivity symptoms in children in the ECHO cohort.

OBJECTIVE: To examine the association between prenatal exposure to a mixture of EDCs and attention-deficit/hyperactivity disorder (ADHD) symptoms in children. METHODS: Participating were mother-child pairs from the Environmental influences on Child Health Outcomes (ECHO) Cohort (n = 3,962, 18 Sites, 2001-2021). Maternal spot urine samples collected during pregnancy were sent to the Wadsworth Center Human Health Exposure Analysis Resource laboratory and analyzed using a single assay workflow. From those samples, 24 urinary metabolites of EDCs with detection frequency > 70%, were grouped as molar sum of high- and low-molecular-weight phthalates, polycyclic aromatic hydrocarbons, bisphenol S, organophosphate esters, and organophosphate and pyrethroid pesticides. Child ADHD symptoms were assessed using raw scores from the Child Behavior Checklist for preschool-aged (CBCL/1½-5) and school-aged (CBCL/6-18) Attention-Deficit/Hyperactivity Problems subscale. Scores ≥ the 85th and 95th percentiles were respectively classified as borderline and clinical thresholds. Quantile g-computation estimated the expected change in ADHD outcome associated with a one-quartile increase in all prenatal EDC mixture concentrations, using negative binomial models for raw scores and binomial models for percentile thresholds. RESULTS: Prenatal exposure to the EDC mixture was not associated with child ADHD symptoms in preschool-aged or school-aged children in adjusted models for either continuous raw scores or percentile thresholds. CONCLUSION: Overall our findings on prenatal EDC mixture exposure and ADHD symptoms were not robust to full adjustment. Future research that can delineate factors such as windows of vulnerability and trajectories of ADHD-related symptoms may help clarify mixed findings in the literature.