Article

The International Collaboration on Air Pollution and Pregnancy Outcomes: Initial Results

National Center for Health Statistics, Centers for Disease Control and Prevention, Hyattsville, Maryland 20782, USA.
Environmental Health Perspectives (Impact Factor: 7.03). 02/2011; 119(7):1023-8. DOI: 10.1289/ehp.1002725
Source: PubMed

ABSTRACT The findings of prior studies of air pollution effects on adverse birth outcomes are difficult to synthesize because of differences in study design.
The International Collaboration on Air Pollution and Pregnancy Outcomes was formed to understand how differences in research methods contribute to variations in findings. We initiated a feasibility study to a) assess the ability of geographically diverse research groups to analyze their data sets using a common protocol and b) perform location-specific analyses of air pollution effects on birth weight using a standardized statistical approach.
Fourteen research groups from nine countries participated. We developed a protocol to estimate odds ratios (ORs) for the association between particulate matter ≤ 10 μm in aerodynamic diameter (PM₁₀) and low birth weight (LBW) among term births, adjusted first for socioeconomic status (SES) and second for additional location-specific variables.
Among locations with data for the PM₁₀ analysis, ORs estimating the relative risk of term LBW associated with a 10-μg/m³ increase in average PM₁₀ concentration during pregnancy, adjusted for SES, ranged from 0.63 [95% confidence interval (CI), 0.30-1.35] for the Netherlands to 1.15 (95% CI, 0.61-2.18) for Vancouver, with six research groups reporting statistically significant adverse associations. We found evidence of statistically significant heterogeneity in estimated effects among locations.
Variability in PM₁₀-LBW relationships among study locations remained despite use of a common statistical approach. A more detailed meta-analysis and use of more complex protocols for future analysis may uncover reasons for heterogeneity across locations. However, our findings confirm the potential for a diverse group of researchers to analyze their data in a standardized way to improve understanding of air pollution effects on birth outcomes.

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    • "Extensive evidence indicates that prenatal exposure to outdoor air pollution is associated with risk of term low birth weight (Brauer et al., 2008; Fleischer et al., 2014; Ghosh et al., 2013, 2012; Hyder et al., 2014; Padula et al., 2012; Parker et al., 2011; Ponce, 2005; Proietti et al., 2013; Ritz and Wilhelm, 2008; Shah and Balkhair, 2011; Stieb et al., 2012; Wilhelm et al., 2011; Wu et al., 2011). While TLBW contributes to racial–ethnic and socioeconomic health disparities in the United States, air pollution is thought to be an important place-based factor in the complex geography of and susceptibly to TLBW (Jerrett and Finkelstein, 2005; Morello- Frosch and Shenassa, 2006). "
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