The causal relationship between sarcopenia traits and abdominal hernia: A bidirectional Mendelian randomization study

Sarcopenia is a potential risk factor for the occurrence of abdominal hernia (AH) after abdominal operation, but their causal relationship is unclear and has been studied to a limited extent. We aimed to explore their relationship using bidirectional Mendelian randomization (MR).

We used the MR-Egger regression and inverse-variance weighted (IVW) as major methods and the instrumental variable of single-nucleotide polymorphisms (SNPs) for causal relationship analysis between sarcopenia traits and AH. The SNPs heterogeneity was assessed using Cochran's Q test and I2 statistic, the pleiotropy of SNPs was evaluated by the intercept term in the MR-Egger method, and the leave-one-out method was used for sensitivity analysis to evaluate the reliability of the results.

Bidirectional MR analysis showed a mutual causal relationship between the sarcopenia-related traits and AH occurrence. Specifically, the forward MR analysis revealed that the sarcopenia traits such as walking pace, appendicular lean mass, hand grip strength (right) and usual walking pace presented a clear causal relationship with AH occurrence, acting as protective factors in AH (OR < 1, P < 0.05). Meanwhile, AH also exhibited a clear causal relationship with the sarcopenia traits including appendicular lean mass, hand grip strength (right) and usual walking pace, acting as protective factors (OR < 1, P < 0.05).

We demonstrated that improving usual walking pace, appendicular lean mass and hand grip strength (right) may lower the risk of AH occurrence. Meanwhile, aggravating AH may lead to a decrease in usual walking pace, appendicular lean mass and hand grip strength (right).