Diabetes and further risk of cancer: a nationwide population-based study

Abstract

Abstract Background Individuals with diabetes have a significantly higher risk of developing various forms of cancer, and the potential biological links between these two diseases are not completely understood. Methods This was a longitudinal retrospective nationwide cohort study, a study design that allows us to examine the natural course of cancer development over an extended period of time with a large sample size. Initially, 3,111,975 and 22,208,395 eligible patients aged ≥ 20 years with and without diabetes, respectively, were matched by age, sex, and the Charlson comorbidity index. Ultimately, 1,751,457 patients were selected from each group. Stratified populations for diabetic retinopathy (DR) (n = 380,822) and without DR (n = 380,822) as well as proliferative DR (PDR) (n = 141,150) and non-proliferative DR (NPDR) (n = 141,150) were analyzed in this study. The main outcome measure was the first-time diagnosis of cancer during the follow-up period. Results We observed a 20% higher risk of total cancer incidence [hazard ratios (HR), 1.20; p < 0.001] in the diabetes cohort compared to the non-diabetes cohort. The highest HR was observed for liver and pancreas cancers. Moderately increased risks were observed for oral, colon, gallbladder, reproductive (female), kidney, and brain cancer. Furthermore, there was a borderline significantly increased risk of stomach, skin, soft tissue, female breast, and urinary tract (except kidney) cancers and lymphatic and hematopoietic malignancies. The stratified analysis revealed that the total cancer incidence was significantly higher in the DR cohort compared to the non-DR cohort (HR, 1.31; p < 0.001), and there was a borderline increased risk in the PDR cohort compared to the NPDR cohort (HR, 1.13; p = 0.001). Conclusions This study provides large-scale, nationwide, population-based evidence that diabetes is independently associated with an increased risk of subsequent development of total cancer and cancer at specific sites. Notably, this risk may further increase when DR develops.