Association between ambient fine particulate matter and adult hospital admissions for pneumonia in Beijing, China

Previous studies have reported conflicting results on the relationship between ambient fine particulate matter (PM2.5) and pneumonia in adults. This study was designed to conduct a time-series study to investigate the short-term association between ambient PM2.5 concentrations and hospitalization for pneumonia in Beijing adults. Hospitalization data were obtained from the Beijing Medical Claim Data for Employees database. A generalized additive model with a Poisson link was applied to assess the relationship between PM2.5 and pneumonia. In total, 37,552 adult hospital admissions for pneumonia were identified between January 1, 2010, and June 30, 2012. High levels of PM2.5 were significantly associated with increased hospitalizations for pneumonia. A 10-mu g/m(3) increase in PM2.5 concentrations on lag days 0-2 was associated with a 0.79% (95% confidence interval: 0.69%-0.90%) increase in hospitalizations for pneumonia. Patients aged >= 65 years were more sensitive to the adverse effects (0.89%, 95% confidence interval: 0.80%-0.98% in patients >= 65 years old; 0.52%, 95% confidence interval: 0.34%-0.70% in patients 18-64 years old; P = 0.033). But the difference of estimates was not significant between sex (0.92%, 95% confidence interval: 0.85%-0.99% in female; 0.76%, 95% confidence interval: 0.62%-0.89% in male; P = 0.781) and season (0.98%, 95% confidence interval: 0.85%-1.10% in cool season; 0.44%, 95% confidence interval: 0.22%-0.67% in warm season; P = 0.529). Short-term exposure to PM2.5 was associated with increased risk of hospitalization for pneumonia in adults. Our findings add new evidence on the effect of air pollution on pneumonia and may promote prevention and intervention strategies.