Estimation of disease burdens on preterm births and low birth weights attributable to maternal fine particulate matter exposure in Shanghai, China.

BACKGROUND: Studies have shown that maternal exposure to particulate matter ≤2.5μm in aerodynamic diameter (PM2.5 ) was associated with adverse birth outcomes such as preterm birth (PTB) and low birth weight (LBW). However, the burdens of PTB and LBW attributable to PM2.5 were rarely evaluated, especially in developing countries.

OBJECTIVES: To estimate the burdens of PTBs and LBWs attributable to outdoor PM2.5 in Shanghai, China.

METHODS: We collected annual-average PM2.5 concentrations, concentration-response relationships between PM2.5 exposure during pregnancy and PTBs and LBWs, rates of PTB and LBW, number of live births, and population sizes in grids of 10km×10km in Shanghai in 2013. Then, they were combined to estimate the odds ratios (ORs), relative risks (RRs), attributable fractions (AFs), and numbers of PTBs and LBWs associated with PM2.5 exposure.

RESULTS: The population-weighted annual-average concentration of PM2.5 in Shanghai was 56.19μg/m3 in 2013. According to the first-class limit of PM2.5 (15μg/m3 ) in the Ambient Air Quality Standards of China, the weighted RRs of PTBs or LBWs associated with PM2.5 in Shanghai were 1.49 [95% confidence interval (CI): 1.16-1.80] and 1.31 (95% CI: 1.04-1.67), respectively. There might be 32.61% (95% CI: 13.93%-44.42%) or 4160 (95% CI: 1778-5667) PTBs and 23.36% (95% CI: 3.86%-40.02%) or 1882 (95% CI: 311-3224) LBWs attributable to PM2.5 exposure. The estimates varied appreciably among different districts of Shanghai.

CONCLUSIONS: Our analysis suggested that outdoor PM2.5 air pollution might have led to considerable burdens of PTBs and LBWs in Shanghai, China.