Causal relationship between benign prostatic hyperplasia and prostate cancer: a bidirectional Mendelian randomization analysis

Objective: Our aim is to explore the relation between benign prostatic hyperplasia (BPH) and prostate cancer (PCa) from a genetic level utilizing Mendelian randomization (MR). Methods: The IEU genome-wide association studies database was surveyed for single nucleotide polymorphisms (SNPs) associated with BPH, PCa, and PCa (validation cohort). Single nucleotide polymorphisms were subjected to stringent quality control based on rigorous screening criteria. BPH and PCa risk were evaluated using the inverse-variance weighted method (IVW), MR-Egger, simple mode, weighted median, and weighted mode. Horizontal pleiotropy of single nucleotide polymorphisms was assessed using the MR-Egger intercept test, while heterogeneity was evaluated using Cochran's Q test. Reverse causality was assessed by evaluating PCa as the exposure and BPH as the outcome. A validation database was used to verify the exposure and outcome. Results: The risk of PCa increased significantly with genetically predicted BPH (IVW: OR [95% CI] = 1.3849 x 107 [2330, 8.2294 x 1010], P = 2.0814 x 10-4). In reverse MR analysis, PCa also increased the risk of BPH (IVW: OR [95% CI] = 1.0011 [1.0003, 1.0019], P = 0.0031). The findings were consistent with the MR analysis results of the PCa validation cohort. Sensitivity analyses indicated the presence of heterogeneity but no horizontal pleiotropy. Conclusion: The study presents proof of a significant bidirectional causal relationship between genetically predicted BPH and an increased risk of PCa.