Preconception, prenatal and postnatal air pollution exposure and risk of neurodevelopmental disorders among Medicaid recipients

Studies examining the association between ambient PM _2.5 exposure and risk of neurodevelopmental disorders (NDDs) in children have yielded mixed results. We conducted a cohort study spanning 2001–2013 among 1,547,244 Medicaid enrollees to quantify the association between zip-code level preconception (12-week), prenatal (37-week), and postnatal (3-year) PM _2.5 exposure and NDD risk among US children. Cox proportional hazards models were used to estimate risks of autism spectrum disorder (ASD), attention-deficit/hyperactivity disorder (ADHD), learning difficulty, developmental speech or language disorder, developmental coordination disorder (DCD), intellectual disability (ID) and behavioral disorder, adjusting for demographics, behavioral factors, meteorological characteristics, and area-level socioeconomic indicators. Distributed lag models examined critical exposure windows and cumulative risks of PM _2.5 exposures. A 10 µg/m ³ increase in cumulative prenatal PM _2.5 exposure was associated with 1.17 (95%CI:[1.00,1.37]) times greater ASD risk. A critical exposure window for ASD existed during gestational weeks 23–31 (HR:1.09 95%CI:[1.02,1.17]). Another critical prenatal exposure window occurred for ADHD at 16–22 weeks gestation (HR:95%CI:[1.01, 1.06]). Cumulative postnatal PM _2.5 exposure was linked with increased DCD risk (HR:1.77 95%CI:[0.93,3.34]), with a critical exposure window at age 2 (HR:1.67 95%CI:[1.13, 2.47]). Prenatal and postnatal PM _2.5 exposure may contribute to increased risk of multiple NDD among US children from low-income families.