The causal effects of genetically predicted sex hormone-binding globulin and sarcopenia: A 2-sample Mendelian randomization study

Observational studies suggest a link between sex hormone-binding globulin (SHBG) and sarcopenia, but the causal relationship is unclear. We conducted a 2-sample Mendelian randomization (MR) study using genome-wide association studies summary data to explore the causal associations between SHBG and traits of sarcopenia, including appendicular lean mass, hand grip strength, and walking pace. Our primary method was inverse-variance weighted, supplemented by weighted median, weighted mode, and MR-Egger regression. Horizontal pleiotropy was assessed using MR-Egger and Mendelian randomization-Pleiotropy Residual Sum and Outlier, with a leave-one-out analysis for robustness. Inverse-variance weighted results showed that there was a causal relationship between genetically predicted SHBG and usual walking pace (odds ratio = 1.04057, 95% confidence interval: 1.01542-1.06635, P = .00144). The results of our study indicate a causal association between SHBG and sarcopenia. Further research is required to confirm these observations and better understand the underlying mechanisms linking SHBG to sarcopenia.