Long-term exposure to ambient air pollution and mortality in a Chinese tuberculosis cohort.

BACKGROUND Evidence for the relationship between exposure to ambient air pollution and the mortality of tuberculosis (TB) patients is limited. METHODS We analyzed the association between long-term exposure to particulate matter <2.5μm in diameter (PM2.5) and cause-specific mortality in a Chinese TB patients cohort from 2003 to 2013. Data from the Global Burden of Disease 2013 estimate were used to assess yearly average concentrations of PM2.5 and ozone at the household addresses of participants. Cox regression was used to calculate adjusted hazard ratios (aHRs) and 95% confidence intervals (CIs) for cause-specific mortality, controlling for demographic and other TB-related factors. RESULTS There were 4444 eligible subjects, including 891 deaths, over a median follow-up of 2464days. Per an interquartile range increase (2.06μg/m3), multivariable analysis indicated that exposure to PM2.5 was significantly associated with overall mortality (aHR=1.30, 95% CI: 1.19, 1.42), mortality from TB (aHR=1.46, 95% CI: 1.15, 1.85), respiratory cancers (aHR=1.72, 95% CI: 1.36, 2.19), other respiratory diseases (aHR=1.19, 95% CI: 1.02, 1.38), and other cancers (aHR=1.76, 95% CI: 1.33, 2.32). CONCLUSIONS Long-term exposure to PM2.5 increases the risk of death from TB and other diseases among TB patients. It suggests that the control of ambient air pollution may help decreasing the mortality caused by TB.