The protective effect of diabetes mellitus against prostate cancer: Role of sex hormones

BACKGROUND Diabetes mellitus (DM) has been associated with decreased risk of prostate cancer (PC) in several reports. Hormonal environment of diabetic patients is believed to be an important contributing factor in this regard. METHODS Using data from a multi‐center case–control study in Iran, base line testosterone, sex hormone binding globulin (SHBG), estradiol, and albumin levels as well as thorough demographic and medical characteristics of 194 newly diagnosed prostate cancer patients were determined. There were 317 ethnicity‐matched men with no cancer as controls as well. Data was analyzed for hormones of interest in DM patients regarding their cancer status. RESULTS Of 511 enrolled patients, twenty‐one cases and 63 controls were diagnosed as DM. Patients with DM were significantly less likely to have PC (OR: 0.44, P = 0.003). Time since DM diagnosis was also inversely correlated with the risk of cancer (P trend