2.1 Study design
In the present study, we utilized two-sample MR studies to evaluate the causal relationship between sarcopenia and COVID-19. We chose four measures of sarcopenia, which included appendicular lean mass (ASM), left-hand grip strength (LH), right-hand grip strength (RH) and usual walking pace (WP). For COVID-19, we selected COVID-19 infection, COVID-19 hospitalization, severe COVID-19 as measures. Additionally, that body mass index (BMI) as a confounding factor, IVs of WP adjusted for BMI were used for further study of the causal connection between COVID-19 and WP.