Air Pollutant Sulfur Dioxide is a Major Risk Factor for Pulmonary Tuberculosis Hospitalizations of HIV-infected Patients: Distribution Lag Non-linear Analyses

Abstract Background: The relationship between air pollutants and pulmonary tuberculosis (PTB) in HIV-infected patients, an immunocompromised population, is unclear.Methods: The data of PTB cases among HIV-infected patients admitted to Guangzhou Eighth People’s Hospital, the local largest HIV/AIDS treatment clinic, as well as the meteorological factors and air pollutants between 2014 and 2019, were collected. The associations between air pollutants and PTB were evaluated in generalized linear model (GLM) and distributed lag non-linear model (DLNM). The robustness of results was tested by sensitivity analysis.Results: A total of 494 subjects were enrolled. PTB cases were decreased over time and significantly correlated with monthly mean concentrations of sulfur dioxide (SO2, r = 0.5, P < 0.001) but not other pollutants. In multi-pollutant GLM, SO2 was a risk factor of monthly PTB cases (relative risk [RR] =1.160, 95% confidence interval [CI]: 1.105-1.218) and fine particulate (PM2.5­) was a protective factor (RR = 0.971, 95% CI: 0.950-0.993). In single-pollutant DLNM, a 10-unit increase in SO2 concentration was significantly related to PTB cases within lag 0-6 months with the peak RR at lag 0 month (RR = 1.201, 95% CI: 1.028-1.403) and linearly decreased over lag months, and the cumulative effect reached the peak at lag 13 month (RR = 3.672, 95% CI = 1.052-12.81). In multi-pollutant DLNM, SO2 remained a risk factor of PTB within lag 0-3 months. PM2.5 was negatively associated with PTB at lag 18 month (RR = 0.900, 95% CI: 0.810-0.999 ) in single-pollutant DLNM and not significant in multi-pollutant DLNM.Conclusions: SO2 is identified as a major risk factor of PTB in HIV-infected patients.