Role of Neighborhood Vulnerability and Opportunity in the Association Between Prenatal Air Pollution and Autism-Related Traits in the ECHO Cohort.

Limited studies have explored the modifying role of neighborhood factors in the association between prenatal air pollution exposure and child neurodevelopment. We investigated whether the relationship between prenatal ambient air pollution and autism-related traits differed by neighborhood-level opportunity and vulnerability. This study drew data from 8,598 mother-child pairs from 35 sites participating in the Environmental influences on Child Health Outcomes (ECHO) Cohort. Ambient air pollutants, including fine particulate matter (PM2.5), nitrogen dioxide (NO2), and ozone (O3), were estimated at residential addresses during pregnancy. The Social Vulnerability Index (SVI) and Child Opportunity Index (COI) at the census tract level were linked to residential addresses at birth. The associations of pregnancy average and trimester-specific air pollution with autism-related traits, as measured by the Social Responsiveness Scale (SRS), stratified by SVI and COI quintiles were evaluated using generalized estimating equation models with a p-value <0.10 for the interaction term as suggestive evidence of signficance. There was evidence of interaction between prenatal exposure to O3 with SRS by SVI (interaction p=0.07) and by COI (interaction p=0.01). Prenatal exposure to O3 during pregnancy was associated with higher SRS score in the lowest SVI (β=0.05, 95% CI: -0.005, 0.10) and highest COI (β=0.04, 95% CI:0.00, 0.08). Differential associations of trimester-specific O3 and PM2.5 by SVI and COI were also observed (interaction p<0.10), although stratified associations within each SVI and COI category were not statistically significant. Our findings suggest that neighborhood level social factors may modify the associaitons between prenatal air pollution and autism-related traits and warrant further consideration of neighborhood factors in environmental epidemiological studies.