Long-term effect of exposure to ambient air pollution on the risk of active tuberculosis

Objectives: To explore the long-term effect of exposure to ambient air pollution on the risk of active tuberculosis (TB). Methods: We constructed a distributed-lag nonlinear model (DLNM) to evaluate the relatively long-term influence of outdoor PM2.5, PM10, SO2 and NO2 exposure on active TB risk in the city of Lianyungang in Jiangsu Province, China. Results: There were 7,282 TB cases reported in the study area during 2014-2017, with annual median (interquartile range) concentrations of PM2.5, PM10, SO2 and NO2 at 45.86 (34.57-64.14) mu g/m(3), 85.43 (62.86-116.14) mu g/m(3), 22.00 (15.71-30.86) mu g/m(3) and 30.00 (23.29-38.57) mu g/m(3), respectively. The single-pollutant model showed that for each 10 mg/m3 increase in concentration, the cumulative relative risk of TB was 1.12 (lag 0-24 weeks, 95% CI: 1.03-1.22) for PM2.5 with reference to 35 mu g/m(3); 1.11 (lag 0-21 weeks, 95% CI: 1.06-1.17) for PM10 with reference to 70 mu g/m(3); 1.37 (lag 0-20 weeks, 95% CI: 1.16-1.62) for SO2 with reference to 60 mu g/m(3); and 1.29 (lag 0-22 weeks, 95% CI: 1.11-1.49) for NO2 with reference to 40 mu g/m(3). In the multipollutant model considering both PM10 and NO2, the association remained significant. Conclusions: Our results revealed a potential association between outdoor exposure to PM2.5, PM10, SO2, and NO2 and active TB. Considering that people from developing countries continue to be exposed to both severe outdoor air pollution and high rates of latent TB infection, the association between worsening air pollution and active TB deserves further attention. (C) 2019 The Author(s). Published by Elsevier Ltd on behalf of International Society for Infectious Diseases.