*Corresponding authors:
Prof. Hai-Feng Pan: Department of Epidemiology and Biostatistics, School
of Public Health, Anhui Medical University, 81 Meishan Road, Hefei,
Anhui, China.
Email address: panhaifeng1982@sina.com, panhaifeng@ahmu.edu.cn.
Abstract:
Objectives: Previous observational studies have revealed a
connection between sarcopenia and COVID-19. To evaluate their causal
relationship, we utilized a bidirectional two-sample Mendelian
randomization (MR) analysis to study the link of cause and effect
between sarcopenia and COVID-19.
Methods: Inverse variance weighting (IVW), MR-Egger, weighted,
and weighted median were used in this research. Then we used the MR
Pleiotropy RESidual Sum and Outlier (MR-PRESSO) and MR-Egger regression
methods to estimate the pleiotropy of instrumental variables (IVs),
while the outliers were excluded by MR-PRESSO. Moreover, we used
Cochran’s Q statistic to evaluate the heterogeneity among the IVs. And
we used leave-one-out sensitivity analysis to identify the SNPs that
significantly affect the outcomes. Finally, the Bonferroni correction
was used to correct each result.
Results: The IVW results suggested that faster WP decreased the
risk of all types of COVID-19 (COVID-19 infection: OR = 0.469, 95% CI:
0.326,0.676, P = 4.82E-05; COVID-19 hospitalization: OR = 0.247,
95% CI: 0.122,0.502, P = 1.11E-04; severe COVID-19: OR = 0.120,
95% CI: 0.046,0.314, P = 1.53E-05). However, there was no causal
relationship between ASM, LH or RH and COVID-19, and WP adjusted for BMI
had no significant connection with all types of COVID-19. Furthermore,
no causal association of COVID-19 on sarcopenia was observed in the
results of reverse MR analysis.
Conclusion: Our bidirectional two-sample MR study suggests the
causal relationship between WP and COVID-19 but it may be caused by the
mediating role of BMI, thus there is no causal association between
sarcopenia and COVID-19.
Keywords: COVID-19; Sarcopenia; Appendicular lean mass; Hand
grip strength; Usual walking pace; Mendelian randomization.