The role of diabetes mellitus in the aetiology of renal cell cancer

To investigate the relation between diabetes mellitus and the risk of renal cell cancer we carried out a population-based retrospective cohort study. Patients identified in the Swedish Inpatient Register who were discharged f rom hospitals with a diagnosis of diabetes mellitus between 1965 and 1983 f ormed a cohort of 153852 patients (80005 women and 73 847 men). The cohort members were followed up to 1989 by record linkage to three nation-wide reg istries. Standardized incidence ratios (SIRs) and standardized mortality ra tios (SMRs) were computed using age-specific sex-specific and period-specif ic incidence and mortality rates derived from the entire Swedish population . After exclusion of the first year of observation, a total of 267 incidenc es of renal cell cancer (ICD-7:180.0) occurred in diabetic patients compare d with the 182.4 that had been expected. Increased risks were observed in b oth women (SIR = 1.7, 95% confidence interval, CI = 1.4-2.0) and men (SIR = 1.3; 95% CI = 1.1-1.6) throughout the duration of follow-up (1-25 years). A higher risk was seen for kidney cancer (ICD-7:180) mortality (SMR = 1.9; 95% CI = 1.7-2.2, women; SMR 1.7, 95% CI = 1.4-1.9, men). In comparison wit h the general population, patients with diabetes mellitus have an increased risk of renal cell cancer.