Diabetes Mellitus and Prostate Cancer Risk—A Systematic Review and Meta-Analysis

Abstract

Introduction: Prostate cancer is the second most commonly diagnosed malignant tumor worldwide and poses a significant challenge to public health. This systematic review and meta-analysis aims to investigate the association between diabetes mellitus and the risk of developing prostate cancer. Methods: We conducted a search of PubMed, Embase, and the Cochrane Library from 1998 to 2024. The risk of bias within the included studies was assessed using the Newcastle–Ottawa Scale. The DerSimonian–Laird random-effect model was employed for the meta-analysis. Heterogeneity was evaluated using a forest plot and statistically assessed via the Q test, I2 index, and p-values. Results: Forty-three studies involving a total of 3,746,769 patients were included. Both case–control (pOR = 0.68, 95% CI: 0.61–0.97; I2 = 92.24%) and cohort studies (pRR = 0.71, 95% CI: 0.59–0.99; I2 = 85.41%) suggest that diabetes mellitus is associated with a reduced risk of prostate cancer, though with significant heterogeneity (p < 0.05). Subgroup analysis revealed that the risk of developing prostate cancer was significantly higher in patients with a family history of prostate cancer (pRR = 1.25, 95% CI: 1.16–1.35; I2 = 69.51%). Conclusions: Our meta-analysis of recent observational studies indicates that diabetes mellitus is associated with a reduced risk of developing prostate cancer.