Type 2 Diabetes Mellitus and the Risk of Prostate Cancer: A Mendelian Randomization Study

Purpose The purpose of this study is to address the current uncertainty surrounding the causal relationship between type 2 diabetes mellitus (T2DM) and prostate cancer. By employing Mendelian randomization studies, we aim to eliminate the influence of confounding factors and clarify the relationship between T2DM and prostate cancer. Understanding the causal effect will contribute to the improvement of prevention and control strategies for both conditions in clinical practice. Methods European population-derived summary data from Genome-Wide Association Studies (GWAS) was utilized to investigate the relationship between T2DM and prostate cancer. T2DM data from 148,726 patients with T2DM and 965,732 controls were included, as well as prostate cancer data from 30,945 prostate cancer patients and 368,725 controls, totaling 399,670 samples. T2DM was utilized as an exposure indicator, and significant and independent SNPs were screened as instrumental variables. A two-sample Mendelian Randomization (MR) approach was used to evaluate the link between T2DM and prostate cancer in the overall sample. Five different methods, including Inverse Variance Weighting (IVW) and MR-Egger, were implemented in the analysis process to establish causal associations. IVW was selected as the main analysis method, and gender heterogeneity was detected by the Cochran Q test. Results Our analysis revealed a positive correlation between T2DM and prostate cancer in the overall population (IVW, OR = 7.88; 95% CI: 6.95–8.93, P < 0.005), indicating a causal relationship. Conclusion Our findings suggest that T2DM does increase the risk of prostate cancer and that a causal relationship between the two does exist.