Exploring the role of diabetes and its interaction patterns with risk factors for lung cancer: A population-based retrospective cohort study.
BACKGROUND Obesity and diabetes are risk factors for cancer at many organ sites. However, their associations with lung cancer remain inconclusive. This study aims to explore the role of diabetes and its interaction patterns with risk factors for lung cancer among the general population. METHODS A territory-wide retrospective cohort study was conducted using electronic health records of Hong Kong. Patients who utilized public healthcare services between 1997 and 2021 without cancer history were identified. Patients were followed up until December 31st, 2021. The role of diabetes and its interaction patterns with risk factors for lung cancer were examined using conditional inference survival tree. RESULTS Of the 191,999 patients included, 2303 patients developed lung cancer during a median follow-up of 6.25 years. Ever smoking, older age, lower LDL cholesterol, the presence of diabetes, and tuberculosis status exhibited an interaction pattern on the risk of lung cancer. Among old ever smokers aged 60 years above characterized by low lipids, the co-occurrence of diabetes and tuberculosis emerged as a key risk factor. In post-hoc analyses, diabetes exhibited interactions with age and lipid profile in ever smokers as well as age alone in never smokers among statin users, but not for statin non-users. CONCLUSIONS The co-occurrence of diabetes and tuberculosis may simultaneously influence the risk of lung cancer, potentially through altered lipid metabolism. It is possible that the opposite characteristics of lipid profile associated with diabetes and tuberculosis may add complexity to the observed association between diabetes and lung cancer. These epidemiological observations may warrant further investigation to validate the findings and future experimental research to elucidate underlying mechanisms.