Preterm birth and PM2.5 in Puerto Rico

Abstract

BackgroundPreterm birth (PTB, birth before 37 weeks of gestation) has been associated with adverse health outcomes across the lifespan. Evidence on the association between PTB and prenatal exposure to air pollutants is inconsistent, but is especially lacking for ethnic/racial minority populations.MethodsWe examined the association between PTB and prenatal exposure to PM2.5 among Hispanic women enrolled in the Puerto Rico Testsite for Exploring Contamination Threats (PROTECT) cohort in municipalities located along the North Coast of Puerto Rico. Exposures were assigned based on nearest Environmental Protection Agency monitor. We used modified Poisson regression to estimate the association, adjusting for potential individual and area-level socioeconomic and behavioral confounders.ResultsAmong 1,116 singleton births, 8.2% of infants were born preterm, and 93% of mothers had at least a high school education. Mothers had a mean (standard deviation) age of 26.9 (5.5) years and a median (range) of 2 (1-8) total pregnancies. Median (range) prenatal PM2.5 concentrations were 6.0 (1.2-19.8) g/m3. An interquartile range increase in PM2.5 was associated with a 1.1% (95% CI 0.4%, 1.6%) higher risk of PTB. In stratified analysis, there was little difference in PTB risk in strata of infant sex, mother’s age (<25 vs >= 25 years), family income (<30K vs >= 30K USD), history of adverse birth outcome, parity, pre-pregnancy body mass index, and degree of prematurity (24-34 weeks vs 34-36 weeks).ConclusionAmong Hispanic women in Puerto Rico, prenatal PM2.5 exposure is associated with a small but significant increase in risk of PTB.