Prenatal exposure to ambient PM components and newborn blood pressure

Abstract

Introduction: Air pollution exposure has been associated with increased blood pressure (BP) in adults. Previously, we found that higher exposures to particle mass (PM2.5) and black carbon in the third trimester of pregnancy were associated with higher newborn BP. We examined associations of antenatal exposure to ambient PM2.5 components with newborn systolic blood pressure (SBP). Methods: We studied 1,131 mother-infant pairs in Project Viva, a Boston-area pre-birth cohort. We measured SBP at a mean age of 30 hours (SD:18) with a Dynamap. We calculated average exposures by trimester and during the 7 to 90 days before birth for a selected group of PM2.5 components: S, Cu, Fe, Zn, Ni, V, Ti, Mg, K, Si, Na, Cl, Ca, Br, Sr, Pb, and Mn. Other elements were excluded either because the analytical measurement was judged to be unreliable or the element had a large proportion of the measurements below the method detection limit. We used mixed effects models to examine associations between PM components and SBP, taking into account measurement circumstances; child's birth weight; mother's age, race/ethnicity, socio-economic position, 3rd trimester BP, and time trend. Estimates represent differences in SBP for the 75th vs. 25th percentile (IQR) of each element. Results: Higher mean S, K, Cu, Ni, Zn, Br, Sr, Pb exposures between the first and the third trimester were associated with higher SBP. An increase (IQR: 0.0006 ng/m3) in the mean 90-day of Pb was associated with 1.06 mmHg (95% CI: 0.45 to 1.66) higher SBP; the result was stable after additionally adjusting for PM2.5. Each 0.0042 ng/m3 increase in mean 90-day Zn was associated with 1.1 mmHg (95% CI: 0.06 to 2.15) higher in SBP. Future work will include multi-metal models and assessment of BP associations with component mixtures. Conclusions: These initial findings suggest that prenatal exposures to PM components, many of which have road dust sources, may influence newborn SBP.