A Population-Based Study of Traffic-Related and Outdoor Air Pollution during Pregnancy and Autism in Denmark

摘要

Background Previous autism spectrum disorder (ASD) and air pollution studies focused on pregnancy exposures, but another vulnerable period is immediate postnatally. Here, we examined early life exposures to air pollution from the pre- to the postnatal period and ASD/ASD subtypes in the Danish population. Methods With Danish registers, we conducted a nationwide case-control study of 15,387 children with ASD born 1989-2013 and 68,139 population controls matched by birth year and sex identified from the birth registry. We generated air dispersion model (AirGIS) estimates for N02, S02, PM2.5 and PM10 at mothers' home from 9 months before to 9 months after pregnancy and calculated odds ratios (OR) and 95% confidence intervals (CI), adjusting for parental age, neighborhood socioeconomic indicators, and maternal smoking using conditional logistic regression. Results In models that included all exposure periods, we estimated adjusted ORs for ASD per interquartile range (IQR) increase for 9 month after pregnancy with N02 of 1.08 (95% CI: 1.01, 1.15) and with PM2.5 of 1.06 (95% CI: 1.01, 1.11); associations were smaller for PM10 (1.04; 95% CI: 1.00, 1.09) and strongest for S02 (1.21; 95% CI: 1.13, 1.29). Also, associations for pollutants were stronger in more recent years (2000-2013) and in larger cities compared with provincial towns/rural counties. For particles and N02, associations were only specific to autism and Asperger diagnoses. Conclusion Our data suggest that air pollutant exposure in early infancy but not during pregnancy increases the risk of being diagnosed with autism and Asperger among children born in Denmark.