Maternal Residential Exposure to Agricultural Pesticides and Birth Defects in a 2003 to 2005 North Carolina Birth Cohort
Birth defects are responsible for a large proportion of disability and infant mortality. Exposure to a variety of pesticides have been linked to increased risk of birth defects. We conducted a case-control study to estimate the associations between a residence-based metric of agricultural pesticide exposure and birth defects. We linked singleton live birth records for 2003-2005 from the North Carolina (NC) State Center for Health Statistics to data from the NC Birth Defects Monitoring Program. Included women had residence at delivery inside NC and infants with gestational ages from 20-44 weeks (n=304,906). Pesticide exposure was assigned using a previously constructed metric, estimating total chemical exposure (pounds of active ingredient) based on crops within 500 meters of maternal residence, specific dates of pregnancy, and chemical application dates based on the planting/harvesting dates of each crop. Logistic regression was used to estimate odds ratios (OR) and 95% confidence intervals (CI) for four categories of exposure (<10th, 10-50th, 50-90th, and >90th percentiles) compared to unexposed. Models were adjusted for maternal race, age at delivery, education, marital status, and smoking status. We observed elevated ORs for congenital heart defects and certain structural defects affecting the gastrointestinal, genitourinary and musculoskeletal systems (e.g., OR (95% CI) (highest exposure vs. unexposed) for tracheal esophageal fistula/esophageal atresia = 1.98 (0.69, 5.66), and OR for atrial septal defects: 1.70 (1.34, 2.14)). Our results suggest associations between residential exposure to agricultural pesticides and several birth defects phenotypes.