Ambient Particulate Matter and Incidence of Respiratory Infection in Children: A Time Series Analysis in Urban Bangladesh

摘要

Exposure to fine particulate matter (PM2.5) has been linked to adverse respiratory outcomes in children. However, the impact of PM2.5 on child health is poorly characterized in regions with high ambient air pollution, including South Asia. This study explores associations between short-term variation in source-specific ambient PM2.5 and incidence of respiratory infection among children in urban Dhaka, Bangladesh. We leverage data from health surveillance of around 5,000 children and infants between 2005 and 2014, including daily counts of physician-confirmed diagnoses from clinic visits. In addition, biweekly source-apportioned ambient PM2.5 measurements were obtained for the same period. Using Poisson regression adjusted for time-varying covariates, we estimate associations between ambient PM2.5 and respiratory infection at time lags of zero to seven days. We find that PM2.5 exposure is associated with an increase in respiratory-related clinic visits at a time lag of two days, and that this association may be driven by increased incidence of lower respiratory infection. For example, a 10 μg/m3 increase in two-day lagged ambient PM2.5 is associated with a 5.1% increase in pneumonia incidence (95% confidence interval = 1.9 - 8.5). The same variation in total PM2.5 was associated with a smaller and nonsignificant increase in upper respiratory infection (URI). Analysis of source-apportioned fine PM indicate that secondary sulfate and the factor attributable to zinc and plastics recycling are most strongly associated with incidence of pneumonia and URI. Results suggest that PM2.5 exacerbates respiratory infections in children, and that ambient air pollution contributes to the high incidence of pneumonia in urban Dhaka.