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Particulate matter, its elemental carbon fraction, and very early preterm birth
Citation:
Rapazzo, K., J. L. Daniels, L. C. Messer, C. Poole, AND D. T. LOBDELL. Particulate matter, its elemental carbon fraction, and very early preterm birth. Presented at International Society for Environmental Epidemiology (ISEE) Annual meeting, Columbia, SC, June 26 - 30, 2012.
Impact/Purpose:
Objectives: To estimate associations between ambient PM <2.5 micrometers in aerodynamic diameter (PM2.5) and its elemental carbon (EC) fraction and EPTB risk in Ohio.
Description:
Background: Particulate matter (PM) has been variably associated with preterm birth, with potentially increased vulnerability during weeks 20-27 of gestation (extremely preterm birth (EPTB)), but the role of PM components have been less studied. Objectives: To estimate associations between ambient PM <2.5 micrometers in aerodynamic diameter (PM2.5) and its elemental carbon (EC) fraction and EPTB risk in Ohio. Methods: We constructed a 20-week gestational age cohort ofpregnancies between 1/1/2000 and 12/31/2005 from live birth certificates (n=612115, 3518 EPTB). We estimated mean PM2.5 and EC exposures over the first 4 weeks of gestation from Community Multi-Scale Air Quality modeling system output corrected with monitoring data. We estimated risk ratios (RR) adjusted for maternal marital status, education, and stratified by race for 1 microgram/cubic meter (ug/m3) increases in PM2.5 and for 0.25 ug/m3increases in EC. Results: Baseline risks (i.e., estimated risk for a fetus carried by a married, high school graduate mother at 5 ug/rrr' PM2.5 or 0.15 ug/m3 EC) were approximately 0.7% in white and 1.8% in black births. For PM2.5, the RRs were 1.009 (95% confidence interval (CI) 0.997, 1.021) among white births and 1.003 (0.988, 1.018) among black births. For EC exposure, the RRs were 1.080 (1.020, 1.144) in white and 1.039 (0.969, 1.113) in black births. Conclusions: Although potential for residual confounding exists, these preliminary results indicatelittle or noassociation of PM2.5 and a positive association of EC early in pregnancy with EPTB risk. This abstract does not necessarily