Pulmonary tuberculosis increases the risk of lung cancer

Background: The possible effect of pulmonary tuberculosis (TB) on subsequent lung cancer development has been suspected, but the evidence remains inconsistent. The purpose of this study was to perform a nationwide population-based cohort study to investigate the risk of lung cancer after pulmonary TB infection. Methods: This nationwide population-based cohort study was based on data obtained from the Taiwan National Health Insurance Database. In total, 5657 TB patients and 23,984 controls matched for age and sex were recruited for the study from 1997 to 2008. Results: The incidence rate of lung cancer (269 of 100,000 person-years) was significantly higher in the pulmonary TB patients than that in controls (153 of 100,000 person-years) (incidence rate ratio [IRR], 1.76; 95% confidence interval [CI], 1.33-2.32; P <.001). Compared with the controls, the IRRs of lung cancer in the TB cohort were 1.98 at 2 to 4 years, 1.42 at 5 to 7 years, and 1.59 at 8 to 12 years after TB infections. The multivariate Cox proportional hazards model revealed pulmonary TB infections (hazard ratio [HR], 1.64; 95% CI, 1.24-2.15; P <.001) and chronic obstructive pulmonary disease (HR, 1.09; 95% CI, 1.03-1.14; P =.002) to be independent risk factors for lung cancer. Conclusions: Pulmonary infection with TB is associated with an increased risk of lung cancer.