(HealthDay News) — Residential proximity to agricultural pesticides during pregnancy is associated with an increased risk of autism spectrum disorders (ASDs) and developmental delay (DD), according to a study published online June 23 in Environmental Health Perspectives.
Janie F. Shelton, MPH, from the University of California, Davis, and colleagues used data from the Childhood Autism Risks from Genetics and Environment (CHARGE) Study to examine the correlation between residential proximity to agricultural pesticides during pregnancy and the risk of ASD or DD. Commercial pesticide application data from the California Pesticide Use Report were linked to pregnancy addresses of 970 participants. The odds ratios of exposure were estimated comparing confirmed cases of ASD (486 cases) or DD (168 cases) with typically developing controls (316 cases).
The researchers found that about one-third of CHARGE Study mothers lived within 1.5km of an agricultural pesticide application during pregnancy. Proximity to organophosphates at some point during pregnancy correlated with a 60% increase in the risk of ASD, which was further elevated for third trimester exposure (odds ratio, 2.0) and second trimester chlorpyrifos applications (odds ratio, 3.3). The risks for ASD and DD were increased for children of mothers residing near pyrethroid insecticide applications just before conception or during the third trimester (odds ratios, 1.7 to 2.3). Those near carbamate applications had an increased risk for DD, but there was no identification of a specific vulnerable period.
“This study of ASD strengthens the evidence linking neurodevelopmental disorders with gestational pesticide exposures, and particularly, organophosphates,” the authors write.