Air Pollution and Autism Spectrum Disorder: Unveiling Multipollutant Risks and Sociodemographic Influences in California.

BACKGROUND

Autism spectrum disorder (ASD) is a neurodevelopmental condition with increasing prevalence worldwide. Air pollution may be a major contributor to the rise in ASD cases. This study investigated how the risk of ASD associated with prenatal and early postnatal exposure to specific air pollutants is modified by key sociodemographic factors, exploring vulnerable exposure periods.

METHODS

We conducted a California population-based cohort study of 44,173 ASD cases among 2,371,379 children born between 2013 and 2018 (California birth registry), linked to California Department of Developmental Services (DDS) records to extract ASD diagnoses prior to the end of 2022. Prenatal and 1-year postnatal air pollution exposures [fine particulate matter with aerodynamic diameter (), nitrogen dioxide (), and ozone ()] were estimated using an advanced land-use regression (LUR) spatiotemporal model with machine learning. Logistic regression was used to estimate odds ratios and 95% confidence intervals for four models: single pollutant at a single period (prenatal or postnatal), multi-pollutant at a single period, single pollutant with dual periods (prenatal and postnatal), and multi-pollutant with dual time period co-adjustment, adjusting for relevant individual and regional covariates.

RESULTS

Prenatal and postnatal exposures increased ASD odds in all models. was associated with ASD pre- and postnatally in single and multi-pollutant models but only postnatally in dual time period models. In contrast, showed the opposite pattern of with slightly negative associations in single and multi-pollutant models that turned positive for the prenatal period in dual time period models. The postnatal effect was strongest among Black and Hispanic children, suggesting higher contributions from traffic-related exposures.

CONCLUSIONS

Exposure to specific air pollutants during pregnancy and in the postnatal periods is associated with an increased risk of ASD, with sociodemographic differences potentially highlighting exposure hot spots and sources as well as subpopulation vulnerabilities. https://doi.org/10.1289/EHP15573.