Association between long-term exposure to ambient air pollutants and the risk of tuberculosis: A time-series study in Nantong, China

Background Increasing evidence has shown that the risk of tuberculosis (TB) might be related to the exposure to air pollutants; however, the findings are inconsistent and studies on long-term air pollutant exposure and TB risk are scarce. This study aime to assess the relationship between monthly exposure to air pollution and TB risk in Nantong, China. Methods We collected the time series data on the number of TB cases, as well as environmental and socioeconomic covariates from January 2005 to December 2020. The impact of air pollutant exposure on TB risk was evaluated using the distributed lag nonlinear model (DLNM). Stratified analyses were conducted to examine the effect modifications of sex and age on the association between air pollutants and TB risk. Sensitivity analyses were applied to test the stability of the model. Results There were a total of 54,096 cases of TB in Nantong during the study period. In the single-pollutant model, for each 10 μg/m 3 increase in concentration, the pooled relative risks (RRs) of TB reached the maximum to 1.10 (95% confidence interval (CI): 1.04–1.16, lag 10 months) for particulate matter with aerodynamic diameter less than 2.5 μm (PM 2.5 ), 1.05 (95% CI: 1.01–1.10, lag 9 months) for particulate matter with aerodynamic diameter less than 10 μm (PM 10 ), and 1.11 (95%CI: 1.04–1.19, lag 10 months) for nitrogen dioxide (NO 2 ). Ozone (O 3 ) did not show significant effect on TB risk. Effect modifications of sex and age on the association between air pollutants and TB risk were not observed. The multi-pollutant model results showed no significant variation compared with the single-pollutant model. Conclusions Our study suggests that air pollutants pose a substantial threat to the TB risk. Reducing air pollution might be crucial for TB prevention and control.