Background: Inhaling fine particles (particulate matter with diameter ≤ 2.5 μm; PM2.5) can induce oxidative stress and inflammation, and may contribute to onset of preterm labor and other adverse perinatal outcomes.
Objectives: We examined whether outdoor PM2.5 was associated with adverse birth outcomes among 22 countries in the World Health Organization Global Survey on Maternal and Perinatal Health from 2004 through 2008.
Methods: Long-term average (2001–2006) estimates of outdoor PM2.5 were assigned to 50-km–radius circular buffers around each health clinic where births occurred. We used generalized estimating equations to determine associations between clinic-level PM2.5 levels and preterm birth and low birth weight at the individual level, adjusting for seasonality and potential confounders at individual, clinic, and country levels. Country-specific associations were also investigated.
Results: Across all countries, adjusting for seasonality, PM2.5 was not associated with preterm birth, but was associated with low birth weight [odds ratio (OR) = 1.22; 95% CI: 1.07, 1.39 for fourth quartile of PM2.5 (> 20.2 μg/m3) compared with the first quartile (< 6.3 μg/m3)]. In China, the country with the largest PM2.5 range, preterm birth and low birth weight both were associated with the highest quartile of PM2.5 only, which suggests a possible threshold effect (OR = 2.54; CI: 1.42, 4.55 and OR = 1.99; CI: 1.06, 3.72 for preterm birth and low birth weight, respectively, for PM2.5 ≥ 36.5 μg/m3 compared with PM2.5 < 12.5 μg/m3).
Conclusions: Outdoor PM2.5 concentrations were associated with low birth weight but not preterm birth. In rapidly developing countries, such as China, the highest levels of air pollution may be of concern for both outcomes.
1University of South Carolina Arnold School of Public Health, Columbia, South Carolina, USA; 2Department of Reproductive Health and Research, World Health Organization, Geneva, Switzerland; 3Department of Physics and Atmospheric Science, Dalhousie University, Halifax, Nova Scotia, Canada; 4School of Medicine, Universidad Nacional Autónoma de México, Mexico City, Mexico; 5Instituto Nacional de Medicina Genomica, Mexico City, Mexico; 6Harvard-Smithsonian Center for Astrophysics, Cambridge, Massachusetts, USA; 7University of Michigan School of Public Health, Ann Arbor, Michigan, USA
Recommended Citation:
Nancy L. Fleischer,1 Mario Merialdi,2 Aaron van Donkelaar,et al. Outdoor Air Pollution, Preterm Birth, and Low Birth Weight: Analysis of the World Health Organization Global Survey on Maternal and Perinatal Health[J]. Environmental Health Perspectives,2014-01-01,Volume 122(Issue 4):425