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Maternal Exposure to Ambient Air Pollution During Pregnancy and Prevalence of Congenital Limb Defects: a Focus on Racial Disparities
Citation:
Luben, Tom, O. Arogbokun Knutson, J. Stingone, L. Engel, C. Martin, AND A. Olshan. Maternal Exposure to Ambient Air Pollution During Pregnancy and Prevalence of Congenital Limb Defects: a Focus on Racial Disparities. Society for Pediatric and Perinatal Epidemiology (SPER), Portland, OR, June 12 - 13, 2023.
Impact/Purpose:
Evaluate the potential for racial disparities in the association between gestational exposure to ambient air pollution and congential limb defects.
Description:
Background: Birth defects account for 20% of all infant deaths; yet, the causes of birth defects remain widely unknown. Among suspected causes are environmental exposures, such as air pollution. Racial disparities in air pollution exposure and congenital limb defect prevalence have been observed. However, racial differences in the association between air pollution exposure during pregnancy and limb defect prevalence have not been investigated. Methods: To investigate the relationship between air pollution and congenital limb defects, we carried out a case-control study using North Carolina birth certificate data (from 2003-2015) linked to the state’s birth defect registry. Particulate matter <2.5 microns (PM2.5) and ozone exposure during weeks 3-9 of pregnancy were assigned to each pregnancy using exposure estimates from the Environmental Protection Agency’s Downscaler Model. A 7-week average of maternal PM2.5 and ozone exposure at the geocoded address at birth were assigned. We created single- and co-pollutant log-binomial models for the full study population and also for racially-stratified analyses that examined non-Hispanic Black and non-Hispanic White pregnancies. Results: We observed positive associations between both pollutants and limb defects. In adjusted, co-pollutant, categorical PM2.5 models, we observed a positive, increasing monotonic trend. The largest prevalence ratio (PR) was seen in the highest exposure concentration of PM2.5 (>12 µg/m3) during pregnancy (aPR (95% CI): 1.16 (0.94, 1.44)). No clear differences were observed in racially-stratified models of PM2.5 and limb defects, though racial differences were seen for ozone. Conclusion: Ambient PM2.5 and ozone exposure early in pregnancy may be associated with increased prevalence of congenital limb defects. Also, exposure to ozone during pregnancy may be impacting non-Hispanic Black and non-Hispanic White pregnancies differently. More epidemiologic studies will be useful to confirm findings.