Blood urea nitrogen and bladder cancer: A Mendelian randomization study

The causal relationship between blood urea nitrogen (BUN) level and bladder cancer (BC) was analyzed by 2-sample Mendel randomization method, in order to provide help for the screening of high-risk groups of BC. Based on the summary data of whole genome association analysis, and Mendelian randomization (MR) is performed using inverse variance weighted (IVW), weighted median (WME), and MR Egger regression methods. IVW analysis is the main result, supplemented by WME and MR Egger regression results. Cochran Q statistics, MR Egger intercept term, MR-PRESSO test, leave 1 out method, and funnel plot are used for sensitivity analysis to ensure the robustness of the analysis results. A total of 178 single nucleotide polymorphisms strongly associated with BUN level were included. IVW analysis showed that there was a causal relationship between blood ureanitrogen and BC (OR = 1.0016, 95% CI: 1.0004-1.0027, P <.05). WME analysis results supported the above conclusions, but MR Egger regression analysis did not show a causal relationship between the 2. Cochran Q statistic P >.05, MR Egger intercept method (P = .63), MR-PRESSO test (P = .36), "leave one out" method, and funnel plot analysis all indicate that there is no heterogeneity or horizontal pleiotropy in the MR analysis of the 2 samples, and the analysis results are stable and reliable. There is a causal relationship between high BUN levels and BC, which provides reference for prevention and treatment of BC.