Perinatal exposure to gaseous pollutants and autism spectrum disorder in children: A nested case-control study in the nurses' health study ii cohort.

Our objective was to explore the association between maternal exposure to gaseous air pollutants and the odds of ASD in their child. We conducted a nested case-control study of participants in the Nurses' Health Study II (NHS II) children born 1990-2002 with ASD (n = 250) and without ASD (n = 1,539) were randomly selected using frequency matching for birth years. The monthly average for each gaseous pollutant O3, NO2, CO, and SO2 were obtained from the daily values from the nearest 5 monitoring stations using distance-weighted averages from the nurse's residence and averaged across months for different exposure windows. Logistic regression models were used to estimate adjusted odds ratios (OR) and 95% confidence intervals (CI) of ASD. Per interquartile range (IQR) increase for each pollutant from mutually adjusted models were: O3 in the 2nd trimester (OR per 0.007 ppm: 1.20; 95% CI: 0.96-1.50); SO2 in the 9 months before pregnancy (OR per 5.54 ppb: 2.26; 95% CI: 1.33-3.83); NO2 in the 3rd trimester (OR per 9.9 ppb = 2.10; 95% CI: 1.03-4.28); and CO in the 3 months after pregnancy (OR per 0.52 ppm: 1.36; 95% CI: 0.71-2.63). Our findings suggest different critical windows of exposure around pregnancy for different air pollutants.