PT - JOURNAL ARTICLE AU - Hye Yun Park AU - Danbee Kang AU - Sun Hye Shin AU - Kwang-Ha Yoo AU - Chin Kook Rhee AU - Gee Young Suh AU - Hojoong Kim AU - Young Mog Shim AU - Eliseo Guallar AU - Juhee Cho AU - O Jung Kwon TI - Chronic obstructive pulmonary disease and lung cancer incidence in never smokers: a cohort study AID - 10.1136/thoraxjnl-2019-213732 DP - 2020 Jun 01 TA - Thorax PG - 506--509 VI - 75 IP - 6 4099 - http://thorax.bmj.com/content/75/6/506.short 4100 - http://thorax.bmj.com/content/75/6/506.full SO - Thorax2020 Jun 01; 75 AB - There has been limited evidence for the association between chronic obstructive pulmonary disease (COPD) and the incidence of lung cancer among never smokers. We aimed to estimate the risk of lung cancer incidence in never smokers with COPD, and to compare it with the risk associated with smoking. This cohort study involved 338 548 subjects, 40 to 84 years of age with no history of lung cancer at baseline, enrolled in the National Health Insurance Service National Sample Cohort. During 2 355 005 person-years of follow-up (median follow-up 7.0 years), 1834 participants developed lung cancer. Compared with never smokers without COPD, the fully-adjusted hazard ratios (95% CI) for lung cancer in never smokers with COPD, ever smokers without COPD, and ever smokers with COPD were 2.67 (2.09 to 3.40), 1.97 (1.75 to 2.21), and 6.19 (5.04 to 7.61), respectively. In this large national cohort study, COPD was also a strong independent risk factor for lung cancer incidence in never smokers, implying that COPD patients are at high risk of lung cancer, irrespective of smoking status.