Preconception, Prenatal and Postnatal PM_2.5 Exposure and Neurodevelopmental Disorder Risk among Medicaid Recipients

We conducted a cohort study (2001–2013) of 1,547,244 Medicaid-enrolled mother-child pairs to assess associations between zip-code–level PM_2.5 exposure during preconception (12-week), prenatal (37-week), and postnatal (3-year) periods and children’s NDD risk. Cox proportional hazards models estimated risks of autism spectrum disorder (ASD), attention-deficit/hyperactivity disorder (ADHD), learning difficulty (LD), speech/language disorder, developmental coordination disorder (DCD), intellectual disability, and behavioral disorder, adjusting for demographics, meteorological characteristics, and area-level socioeconomic indicators.

Distributed lag models assessed critical exposure windows and cumulative effects. A 10 μg/m³ increase in cumulative prenatal PM_2.5 exposure was associated with higher ASD risk (Hazard ratio (HR):1.17; 95%CI:1.00,1.37). A critical exposure window for ASD existed during gestational weeks 23–31 (HR:1.09 95%CI:[1.02,1.17]).