Using new satellite based exposure methods to study the association between pregnancy PM₂.₅ exposure, premature birth and birth weight in Massachusetts

Department of Environmental Health-Exposure, Epidemiology and Risk Program, Harvard School of Public Health, Landmark Center, 401 Park Dr West, Boston, MA 02215, USA.
Environmental Health (Impact Factor: 3.37). 06/2012; 11(1):40. DOI: 10.1186/1476-069X-11-40
Source: PubMed


Adverse birth outcomes such as low birth weight and premature birth have been previously linked with exposure to ambient air pollution. Most studies relied on a limited number of monitors in the region of interest, which can introduce exposure error or restrict the analysis to persons living near a monitor, which reduces sample size and generalizability and may create selection bias.
We evaluated the relationship between premature birth and birth weight with exposure to ambient particulate matter (PM₂.₅) levels during pregnancy in Massachusetts for a 9-year period (2000-2008). Building on a novel method we developed for predicting daily PM₂.₅ at the spatial resolution of a 10x10 km grid across New-England, we estimated the average exposure during 30 and 90 days prior to birth as well as the full pregnancy period for each mother. We used linear and logistic mixed models to estimate the association between PM₂.₅ exposure and birth weight (among full term births) and PM₂.₅ exposure and preterm birth adjusting for infant sex, maternal age, maternal race, mean income, maternal education level, prenatal care, gestational age, maternal smoking, percent of open space near mothers residence, average traffic density and mothers health.
Birth weight was negatively associated with PM₂.₅ across all tested periods. For example, a 10 μg/m³ increase of PM₂.₅ exposure during the entire pregnancy was significantly associated with a decrease of 13.80 g [95% confidence interval (CI) = -21.10, -6.05] in birth weight after controlling for other factors, including traffic exposure. The odds ratio for a premature birth was 1.06 (95% confidence interval (CI) = 1.01-1.13) for each 10 μg/m3 increase of PM₂.₅ exposure during the entire pregnancy period.
The presented study suggests that exposure to PM₂.₅ during the last month of pregnancy contributes to risks for lower birth weight and preterm birth in infants.

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Available from: Itai Kloog, May 19, 2014
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    • "For each of the pollutants, we estimated second-trimester exposures by averaging daily concentrations from day 94 through day 187 after last menstrual period. We estimated neighborhood traffic density [average daily traffic (vehicles/day) × length of road (kilometers) within 100 m] using the 2002 road inventory from the Massachusetts Executive Office of Transportation [as in Kloog et al. (2012); Zeka et al. (2008)]. Home roadway proximity (distance to census feature class code A1 or A2 roads) was calculated using U.S. and Canada detailed streets from Street Map TM North America ArcGIS 10 Data and Maps (time period of content 2005; ArcGIS). "
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