title: Reduced risk of prostate cancer among patients with diabetes mellitus.
abstract: Although diabetes mellitus is associated with an increased risk of several malignancies, a negative association with prostate cancer is biologically most plausible. The epidemiologic evidence is, however, inconsistent, limited and based mostly on small studies. We present results from a large, population-based cohort study in Sweden, where we assessed prostate cancer risk among patients hospitalized for diabetes mellitus. 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 (SIRs), with 95% confidence interval (CI), were used as a measure of relative risk. After complete exclusion of the first year of follow-up (to avoid selection bias), 135,950 men remained in the cohort, contributing 827,099 years of follow-up to the study. A total of 2,455 incident cases of primary prostate cancer were identified during 1-31 years of follow-up, yielding an overall SIR of 0.91 (95% CI 0.87-0.94); this risk reduction was more pronounced among patients who have been hospitalized for diabetic complications (SIR = 0.82; 95% CI 0.74-0.91). We found no consistent trends in risk related to age at first hospitalization or to duration of follow-up. We did find a small, but significantly decreased risk of prostate cancer among men who had been hospitalized for diabetes mellitus.
authors.affiliation: Unit of Field and Intervention Studies, International Agency for Research on Cancer, 150 Cours Albert-Thomas, F-69372 Lyon Cedex 08, France. weiderpass@iarc.fr
authors.forename: Elisabete
authors.initials: E
authors.lastname: Weiderpass
authors.forename: Weimin
authors.initials: W
authors.lastname: Ye
authors.forename: Harri
authors.initials: H
authors.lastname: Vainio
authors.forename: Rudolf
authors.initials: R
authors.lastname: Kaaks
authors.forename: Hans-Olov
authors.initials: HO
authors.lastname: Adami
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D015331:Cohort Studies; D048909:Diabetes Complications; D003920:Diabetes Mellitus / Q000453:epidemiology; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D008875:Middle Aged; D011471:Prostatic Neoplasms / Q000150:complications* / Q000453:epidemiology; D012042:Registries; D012306:Risk; D013548:Sweden; D013997:Time Factors