Pulmonary Tuberculosis is Associated with Elevated Risk of Lung cancer in Korea: The Nationwide Cohort Study

Objective: Although previous studies suggest that previous pulmonary tuberculosis was associated with increased risk of lung cancer. It remains controversial whether pulmonary tuberculosis is a risk factor for lung cancer. Our study was aimed to examine the association between pulmonary tuberculosis and lung cancer risk in Korean. Methods: The Korean National Health and Nutrition Examination Survey database was linked with the Korean National Cancer Incidence Database to examine the occurrence of pulmonary tuberculosis and lung cancer. The linked databases were also merged with causes of death database of Statistics Korea. The Cox-proportional hazards model was used to estimates the hazard risk of lung cancer for Korean adults aged >/=40 years with pulmonary tuberculosis. Results: Of 20,252 total participants, 2,640 (13.0%) had old pulmonary tuberculosis (a medical history of pulmonary tuberculosis or radiologically inactive tuberculosis). After adjusting for all covariates, the hazard ratio of lung cancer among patients with old pulmonary tuberculosis was 3.24 (95% CI, 1.875.62) compared to the control group. According to smoking status, the hazard ratios of lung cancer for never smokers, ex-smokers, and current smokers among participants with old pulmonary tuberculosis were 3.52 (95% CI, 1.1710.63), 2.16 (95% CI, 0.895.24), and 3.71 (95% CI, 1.499.22) compared to the control group, respectively. Conclusions: Korean adults with old pulmonary tuberculosis have a higher risk of lung cancer, compared to general population without pulmonary tuberculosis.