Prenatal PM2.5 exposure and neurodevelopment at 2 years of age in a birth cohort from Mexico city

Background: Recent studies have reported that air pollution exposure may have neurotoxic properties. Objective: To examine longitudinal associations between prenatal particles less than 2.5 mu m in diameter (PM2.5) exposure and neurodevelopment during the first two years of children's life. Methods: Analysis was conducted in PROGRESS, a longitudinal birth cohort between 2007 and 2013 in Mexico City. We used satellite data to predict daily PM2.5 concentrations at high spatial resolution. Multivariate mixed-effect regression models were adjusted to examine cognitive, language and motor scores in children up to 24 months of age (n = 740) and each trimester-specific and whole pregnancy exposure to PM2.5. Results: Models adjusted by child sex, gestational age, birth weight, smoking and mother's IQ, showed that each increase of 1 mu g/m(3) of PM2.5 was associated with a decreased language function of 0.38 points (95% CI: 0.77, 0.01). PM2.5 exposure at third trimester of pregnancy contributed most to the observed association. Conclusion: Our findings suggest that language development up to 24 months of age may be particularly sensitive to PM2.5 exposure during pregnancy.