New findings on the effects of diabetes and anti-diabetic drugs on prostate cancer.

Although diabetes mellitus (DM) is known to be related to the risk of many cancers, there are few studies on the risk of prostate cancer (PC) depending on the status of hyperglycemia, such as prediabetes and DM. Thus, the objective of this study was to determine the effect of each status of hyperglycemia on the risk of PC. In a Korean National Health Insurance Service database cohort, a total of 560,413 individuals who were followed until 2018 were analyzed. The risk of PC in patients with impaired fasting glucose (IFG) and new onset DM as well as all DM was determined. Associations of metabolic syndrome (MetS) components with the risk of PC according to glycemic status were evaluated. The association of anti-diabetic drugs with the incidence of PC was also analyzed. The presence of new-onset and all DM showed a significant reduction of the risk of PC in adjusted models. There was a trend that the presence of DM reduced the risk of PC regardless of the presence of MetS components. Regarding associations of anti-diabetic drugs with the incidence of PC, DM patients who were taking less than three drugs of oral hypoglycemic agents including metformin showed a reduced risk of PC compared to patients without using metformin. This study supports an inverse relationship between DM and the risk of PC. However, the risk of PC can be different depending on glycemic status and sorts of anti-diabetic drugs.