Impedance of whole body plays a crucial role in the pathway from rheumatoid arthritis to prostate cancer: a Mendelian randomization study

Background: An earlier observational study has indicated a potential link between rheumatoid arthritis and a higher chance of developing prostate cancer, but the exact causal direction and the role of impedance of whole body in this association remain unclear. To address this gap in knowledge, we conducted two-sample univariable and multivariable MR analyses to assess the total and direct effects of rheumatoid arthritis and whole-body impedance on prostate cancer risk. Methods: : The primary estimate was derived using the inverse-variance weighted method, and additional methods such as MR Pleiotropy . We conducted two-sample univariable and multivariable MR analyses to assess the total and direct effects of rheumatoid arthritis and whole-body impedance on prostate cancer risk. Two-sample Mendelian randomization (MR) was utilized to examine the independent causal effects of rheumatoid arthritis on whole-body impedance. The primary estimate was derived using the inverse-variance weighted method, and additional methods such as MR Pleiotropy RESidual Sum and Outlier, MR-Egger, and weighted median were employed to detect any heterogeneity or pleiotropy. In our meta-analysis, we found that both rheumatoid arthritis and impedance of whole body were associated with an increased risk of prostate cancer (rheumatoid arthritis: OR = 1.03, 95% CI = 1.01−1.05, p=0.003; impedance of whole body: OR =1.11, 95% CI =1.02 -1.20, P =0.015). Furthermore, the MR analysis provided evidence to support the notion that rheumatoid arthritis can increase the risk of impedance of whole body (OR= 1.01.95% confidence interval [CI] 1.004-1.013; p = 0.0002). There was little evidence that rheumatoid arthritis influenced prostate cancer once impedance of whole body was controlled for, whereas impedance of whole body could significantly affect prostate cancer independently of rheumatoid arthritis (IVW: p=0.018). Results: : Mendelian randomization study offers evidence to support the idea that impedance of whole body seems to have a significant impact on the link between rheumatoid arthritis and prostate cancer.