Apples to Apples: comparing PM2.5 exposures and birth outcomes in understudied countries.

摘要: Mixed evidence suggests inhalation of fine particulate matter (PM2.5), a component air pollution, may adversely affect birth outcomes, and research to elucidate the potential connection is ongoing.1 A new study in EHP provides further for previously described associations between PM2.5 levels low weight,2,3 but it goes step farther by focusing on low- middle-income countries, which have generally been excluded from previous analyses.1 Only China was increased estimated exposure associated with higher likelihood both preterm weight. had highest average exposures 22 countries studied. In pregnant women, provoke oxidative stress inflammation, cause endocrine disruption, impair oxygen transport across placenta, all can potentially lead weight (defined as less than 2,500 g) (before 37th week pregnancy).1,4 Aside immediate consequences infancy, health throughout childhood adulthood.3,5,6,7 The exclusion earlier studies arose largely lack dependable data. Health-related pollution relies heavily data gathered monitoring stations, are most often placed urban areas developed countries.8,9 These stations provide precise pollutant concentrations at particular locations. Exposure beyond these points be extrapolated adjusting factors such traffic meteorological patterns, only certain extent.5 The current took different approach, using 2001–2006 satellite data8 estimate maternal month prior birth; where available, ground-monitoring were used confirm satellite-based estimates. The included 192,900 live births Africa, Latin America, Asia, collected through World Health Organization Global Survey Maternal Perinatal (WHOGS).10 Data standard information participating care facilities during 2- 3-month periods September 2004 April 2008. The statistical analysis two models. first provided global while controlling (e.g., age, education, parity) infant sex. second additionally controlled country-specific factors, income, urbanicity, availability prenatal care, per-capita expenditures proxies broader development. Results models showed that reduction not birth, one exception: “In rapidly developing high China, concern weight,” says author Nancy L. Fleischer, an assistant professor epidemiology biostatistics University South Carolina. A key strength data-collection method multiple countries. also several limitations. “The use imaging very clever idea,” David A. Savitz, obstetrics gynecology Brown University. “But there real compromises made do so—mainly they could examine spatial, temporal variation; able align pregnancies precisely; assigned same score within fifty kilometers clinic women received without being take into account lived,” he says. The researchers discuss limitations their report, point out indoor pollutants influence unmeasured confounding factors. “Hopefully, this will spur collect better measurements local, detailed outcomes,” Fleischer. Savitz agrees more reliable needed. “I see avenues progress,” says. “One identify truly susceptible among whom causes substantial increase risk, subtle effects reported studies. other avenue would mechanistic tightly demonstrate intermediate links pathways known fetal growth.”