Objective: We present results from a large, population-based cohort study in Sweden, where we assessed ovarian cancer risk among patients hospitalized for diabetes mellitus.
Methods: The cohort was composed of patients identified in the Swedish In-Patient Register as having a hospital discharge diagnosis of diabetes mellitus in 1965-1994. The follow-up was done by linkages with the national cancer register and other population-based registers. Standardized incidence ratios (SIR) were used as a measure of relative risk.
Results: After exclusion of the first year of follow-up (to avoid selection bias), 141,627 women remained in the cohort, contributing 865,746 years of follow-up to the study. The overall SIR for ovarian cancer was 0.97 (95% confidence interval (CI) 0.87-1.08). We found no difference in the risk estimates among women who had been hospitalized for classic complications of diabetes and for those who had not, or according to the duration of follow-up. Women above 40 years of age at first hospitalization presented a SIR of 0.96 (95% CI 0.85-1.07).
Conclusions: Our study provides evidence of lack of an association between diabetes mellitus and ovarian cancer.