Individual Exposure to Nitrogen Dioxide and Preterm Birth Risk in Kaunas
Keywords: Nitrogen dioxide, exposure, modelling, preterm birth
AbstractSeveral epidemiological studies have found relationships between exposures to air pollution and adverse birth outcomes, particularly for traffic-related air pollutants, suggesting that the exposure may increase risk of preterm birth. Nitrogen dioxide (NO2) is the main traffic-related urban air pollutant associated with health effects. The purpose of this study was to assess individual maternal exposure to NO2 during pregnancy and to study links between the exposure and preterm birth risk in Kaunas, Lithuania. Prospective cohort study comprised all singleton newborns, born to Kaunas citizens in 2008-2009. Case group consisted of 187 preterm births (< 37 weeks), while controls were 3100 term (≥ 37 weeks) singleton newborns. Individual exposure to NO2 was assigned to each subject during each trimester pregnancy as well as throughout the entire pregnancy by using a dispersion air quality modelling system AIRVIRO. To assess the association between preterm birth and exposure to NO2 logistic regression analysis was used and odds ratios (OR) and their 95% confidence intervals (95% CI) were calculated. Pregnant women exposed to NO2 have a slightly increased risk of preterm birth. That risk was shown to be higher when women were exposed to NO2 levels 24.0-53.2 µg m-3 during the first and second trimesters, OR 1.21, 95% CI 0.84-1.75 and 1.22, 95% CI 0.84-1.76, respectively. The study results indicate that residential air pollution might contribute to preterm birth risk.
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