Nitrogen dioxide exposure dispersion modelling for assessment of preterm birth risk

Abstract

There is some evidence from epidemiological studies that maternal exposure to air pollutants during pregnancy may increase the likelihood of adverse birth effects. Results are not consistent becouse of crude and various exposure evaluation but suggest that adverse effects of nitrogen dioxide (NO2) on preterm birth may occur. The purpose of this study was to assess individual maternal exposure during pregnancy to NO2 using dispersion modelling and to analyse the links between NO2 exposure and preterm birth risk. We conducted a prospective cohort study of 4,161 pregnant women in Kaunas (Lithuania). Case group consisted of 167 preterm births (< 37 weeks), while controls were 2846 term (≥ 37 weeks) singleton newborns. Individual exposure to NO2 was assigned to each subject during 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. NO2 exposure tended to be associated with increase in risk of preterm birth after adjustment for the main possible confounders. Adjusted odds ratios for preterm birth for entire pregnancy exposed to third versus first tertile NO2 was found to be 1.44, 95 % CI 0.98–2.11. The risk of preterm birth increased by 22 % (adjusted OR = 1.22, 95 % CI 0.94–1.56) per 10 μg m-3 increase in NO2 concentrations. The study results indicate that residential NO2 exposure might contribute to the risk of preterm birth.