2013 Environment and Health - Basel
Exposure to Particulate Matter Air Pollution during Pregnancy Is Associated With Increased Risk for Autism Spectrum Disorder
Background: Air pollution contains many toxicants known to affect neurological function and to have effects on the fetus in utero. Several case-control studies have already found increased risk for autism spectrum disorder (ASD) with exposure to air pollutants. Particulate matter ?2.5?m (PM2.5) and ?10?m (PM10) have specifically been implicated in two California studies.
Aims: To estimate the risk of ASD with exposure to PM2.5 and PM10 during pregnancy in a large US cohort.
Methods: We identified 209 ASD cases (184 males; 25 females) and 1259 controls among children of Nurses’ Health Study II participants, for whom we had residential addresses prior to pregnancy. Cases were identified by maternal report, validated with the Autism Diagnostic Interview-Revised in a subset. Residence-specific monthly PM levels were estimated from a validated spatial-temporal model. General additive logistic models with penalized splines were used to estimate odds ratios (OR) and 95% confidence intervals (CI) for ASD, adjusting for birth year, child sex, parent education, mother’s age, father’s age and income. Results: In the full sample, PM2.5 exposure averaged over pregnancy was associated with a linear increase in risk for ASD, with an OR of 1.39 (95% CI: 1.13-1.71) per IQR change in PM2.5 (4.13 µg/m3). Pregnancy trimester specific associations, as well as associations with exposure during time periods before or after the pregnancy, were weaker. PM10 was not associated with risk for ASD (OR=1.04 per IQR change in PM10 [7.39 µg/m3], 95% CI: 0.94-1.15). When stratified be sex, PM2.5 was associated with increased risk for ASD in males (OR=1.41, 95%CI 1.13-1.77), but not in females (OR=1.21, 95%CI 0.69-2.12).
Conclusions: Our data support an association between exposure to PM2.5, but not PM10, during pregnancy and increased risk of ASD. The association may be limited to males, but the number of female cases was small.