Type 2 diabetes mellitus does not increase the risk of lung cancer among never-smokers: a nationwide cohort study

Previous studies have reported higher incidences of lung cancer among smokers diagnosed with diabetes than those without. Accordingly, this study investigated whether type 2 diabetes mellitus (T2DM) diagnosis alone can be associated with increased lung cancer incidences among never-smokers in the Korean population. Newly diagnosed never-smoking T2DM patients were identified from the nationwide longitudinal cohort of health examination data of South Korea (2002–2013). Cox proportional hazards regression model was employed to estimate the hazard ratios (HRs) and 95% confidence interval (CI) of lung cancer in the T2DM patient and abnormal fasting blood sugar (FBS) groups. T2DM (HR =0.91, 95% CI: 0.71 to 1.17) and abnormal FBS level are no significant association with lung cancer incidence based on the given HR. T2DM does not increase the risk of lung cancer among never-smokers. A large cohort study affirms minimal impact of T2DM on lung cancer development in the never-smoking Korean population.