Prenatal Air Pollution Exposure and Autism Spectrum Disorder in the ECHO Consortium

Area of Science:

• Environmental Health Sciences
• Pediatric Epidemiology
• Neurodevelopmental Disorders

Background:

• The impact of low-level prenatal air pollution on child autism spectrum disorder (ASD) remains incompletely understood.
• Existing research has not definitively established a clear link between environmental exposures during pregnancy and ASD development.

Purpose of the Study:

• To investigate the associations between prenatal exposure to specific air pollutants and autism-related traits in children.
• To examine the relationship between fine particulate matter (PM_2.5), nitrogen dioxide (NO₂), and ozone (O₃) exposure during pregnancy and the risk of ASD diagnosis.

Main Methods:

• Analysis of data from 8,035 mother-child pairs across 44 US cohorts within the Environmental influences on Child Health Outcomes (ECHO) Cohort.
• Estimation of residential air pollutant levels (PM_2.5, NO₂, O₃) during pregnancy.
• Assessment of autism-related traits using the Social Responsiveness Scale (SRS) and physician-diagnosed ASD, analyzed via quantile and logistic regression, with pooled meta-analysis across census divisions.

Main Results:

• Higher prenatal PM_2.5 exposure was associated with increased SRS scores at the 10th quantile.
• Prenatal ozone (O₃) exposure showed associations with higher SRS scores at the median and 90th quantiles, and with ASD diagnosis.
• Significant heterogeneity was observed in the associations between PM_2.5, NO₂, and SRS scores across different US census divisions.

Conclusions:

• Prenatal exposure to air pollutants, including PM_2.5 and O₃, is associated with autism-related traits and ASD diagnosis.
• These environmental risks appear to be present even at low levels of air pollution exposure.
• Geographic variations in associations suggest complex environmental and potentially genetic interactions influencing ASD development.