Assessing the impact of air pollution on birth defects and potential for modification by residential built food environment
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Air pollution is a risk factor for adverse birth outcomes, yet its association with congenital anomalies remains underexplored. Additionally, lack of access to healthy food can cause undernutrition during pregnancy and result in adverse birth outcomes, including congenital anomalies. We evaluated associations between Coarse particulate matter (PM10), fine particulate matter (PM2.5), PM2.5 components, NO2 and O3 exposure during the periconceptional period and early pregnancy and 30 birth defects phenotypes, including neural tube defects and congenital heart defects. Using the North Carolina Birth Cohort from 2003 to 2015 (N = 1,367,517), we constructed matched case-control analytic data sets for each birth defect phenotype, matching on year and region of birth. We assigned exposure for the periconceptional period, early gestation, and the combined periconceptional and early gestational periods. Air pollution predictions from EPA’s spatiotemporal CMAQ EQUATES model, with daily temporal resolution and census tract spatial resolution, were linked with residential address and assigned to exposure periods. We fit logistic regression models to estimate the odds of individual birth defect phenotypes in relation to increases in ambient air pollution concentrations and calculated odds ratios (ORs) and 95% confidence intervals (CIs). We observed mixed results. For example, O3 exposure during the periconceptional period was positively associated with ventral septal defects (OR: 1.17 (95% CI: 1.02, 1.35), and negatively associated with atrial septal defects (OR: 0.85 (95% CI: 0.77, 0.94). We used stratified models to evaluate the potential for residence in a low food access census tract to modify the association between air pollution and birth defects. Data on low food access census tracts were derived from the USDA's Food Access Research Atlas. Our results provide insights into environmental risk factors for fetal development, contribute to the growing body of evidence on air pollution’s role in congenital anomalies and inform public health strategies aimed at reducing exposure-related risks during pregnancy.