Prenatal Air Pollution Exposure and Newborn Blood Pressure

Background: Air pollution exposure has been associated with increased blood pressure in adults. Objective: We examined associations of antenatal exposure to ambient air pollution with newborn systolic blood pressure (SBP). Methods: We studied 1,131 mother-infant pairs in a Boston, Massachusetts, area pre-birth cohort. We calculated average exposures by trimester and during the 2 to 90 days before birth for temporally resolved fine particulate matter (<= 2.5 mu m; PM2.5), black carbon (BC), nitrogen oxides, nitrogen dioxide, ozone (O-3), and carbon monoxide measured at stationary monitoring sites, and for spatiotemporally resolved estimates of PM2.5 and BC at the residence level. We measured SBP at a mean age of 30 +/- 18 hr with an automated device. We used mixed-effects models to examine associations between air pollutant exposures and SBP, taking into account measurement circumstances; child's birth weight; mother's age, race/ethnicity, socioeconomic position, and third-trimester BP; and time trend. Estimates represent differences in SBP associated with an interquartile range (IQR) increase in each pollutant. Results: Higher mean PM2.5 and BC exposures during the third trimester were associated with higher SBP (e.g., 1.0 mmHg; 95% CI: 0.1, 1.8 for a 0.32-mu g/m(3) increase in mean 90-day residential BC). In contrast, O-3 was negatively associated with SBP (e.g., -2.3 mmHg; 95% CI: -4.4, -0.2 for a 13.5-ppb increase during the 90 days before birth). Conclusions: Exposures to PM2.5 and BC in late pregnancy were positively associated with newborn SBP, whereas O-3 was negatively associated with SBP. Longitudinal follow-up will enable us to assess the implications of these findings for health during later childhood and adulthood.