Association between prenatal exposures to ambient air pollutants and preterm birth in the Atlanta African American Mother-Child Cohort

Abstract

BACKGROUND AND AIM: Exposures to air pollution during pregnancy have been associated with preterm birth (PTB). Communities of color, especially African American (AA), are disproportionately exposed to high levels of air pollution and experience elevated occurrences of PTB, warranting investigation into the attributable risk of PTB among AA women associated with prenatal exposure to ambient air pollution. METHODS: This study was conducted in the Atlanta AA Maternal-Child cohort. We linked ambient PM2.5, NO2, and O3 concentrations at 1-km resolution to 293 participants who delivered between 2014 and 2016. We used both single- and multi-pollutant logistic models with adjustment for potential confounders (i.e., sociodemographic, socioeconomic status, behavioral risk factors, season of conception, and meteorology) to examine associations between pollutant exposures (during each trimester, entire pregnancy, and 3 years before pregnancy) and PTB ( 37 weeks) and early-term birth (37-38 weeks) vs. full term birth. RESULTS:PM2.5 concentrations (in both single- and 3-pollutant models) and NO2 (single pollutant model) during the three years before pregnancy were associated with increased odds of PTB. In the 3-pollutant model, the odd ratio (OR) for PTB was 1.66 (95% CI: 1.01-2.73) per interquartile range (IQR) increase in NO2 throughout pregnancy. Both single- and 3-pollutant models showed NO2 levels during the 1st and 2nd trimesters, and during the entire pregnancy were significantly associated with increased odds of early-term birth; corresponding ORs for per IQR increment were 1.78, 1.63, and 1.52, respectively. PM2.5 during the 3rd trimester was also associated with elevated risk for early term birth in a single pollutant model (OR 1.95, 1.08-3.50). CONCLUSIONS:Long-term exposures to PM2.5 and NO2 before and during pregnancy were associated with preterm and early-term birth in the Atlanta AA birth cohort. This study supports targeted interventions to protect pregnant women from air pollution, especially AA populations who have a higher PTB rate. KEYWORDS: Air pollution, Multi-pollutant, Birth outcome