Maternal Exposure to Local, Source-specific Ambient Air Pollution During Pregnancy and Autism in Children: a Cohort Study From Southern Sweden

Abstract

Evidence of air pollution exposure, namely, ambient particulate matter (PM), during pregnancy and an increased risk of autism spectrum disorders (ASD) in children is growing. Which PM sources contribute to this association is currently unknown, however. The aim of the present study was to investigate local source-specific ambient PM exposure and its association with ASD. A cohort of 48,571 singleton births from 1999 to 2009 in Scania, Sweden, was combined with data on locally emitted PM with an aerodynamic diameter <2.5 µm (PM2.5). A flat, two-dimensional dispersion model was used to model PM2.5 exposure (all-source PM2.5, tailpipe exhaust, vehicle wear-and-tear, and small-scale residential heating- mainly wood burning) at the residential address. Associations were analyzed using binary logistic regression in partially and fully adjusted models. Clear associations were observed between PM2.5 and ASD, with statistical significance for all investigated sources in the partially adjusted model. In the fully adjusted model, only all-source PM2.5 was statistically significant. The results add to existing evidence that exposure to air pollution during pregnancy may be associated with an increased risk for ASD among children. Further, these findings suggest that locally emitted tailpipe exhaust, vehicle wear-and-tear, and small-scale residential heating all contribute to this association.