Disentangling the association between chronic pain and sarcopenia-related traits: A bidirectional Mendelian randomization study
Objective This study aimed to investigate the potential causal relationships between chronic pain and three key sarcopenia-related quantitative traits: (a) hand grip strength; (b) usual walking pace; and (c) appendicular lean mass, using bidirectional two-sample Mendelian randomization. Methods We conducted bidirectional two-sample Mendelian randomization using summary-level data from large-scale genome-wide association studies to assess the genetically predicted associations between chronic pain, including multisite chronic pain and chronic widespread musculoskeletal pain, and the aforementioned sarcopenia-related traits. Results Mendelian randomization revealed that multisite chronic pain was significantly associated with an increased risk of low hand grip strength (odds ratio = 1.70; p < 0.001) and decreased usual walking pace (odds ratio = 0.81; p < 0.001); chronic widespread musculoskeletal pain was also significantly associated with decreased usual walking pace (odds ratio = 0.15; p < 0.001). Additionally, higher left hand grip strength was significantly associated with a lower risk of multisite chronic pain (odds ratio = 0.90; p< 0.001) and chronic widespread musculoskeletal pain (odds ratio = 0.99; p = 0.002); higher right hand grip strength was significantly associated with a lower risk of multisite chronic pain (odds ratio = 0.91; p = 0.002); and higher usual walking pace was significantly associated with a lower risk of multisite chronic pain (odds ratio = 0.49; p < 0.001) and chronic widespread musculoskeletal pain (odds ratio = 0.92; p < 0.001). No significant causal associations were detected for appendicular lean mass in either direction (all p > 0.05). Conclusion This study provides genetic evidence supporting potential causal links between chronic pain and key phenotypic components of sarcopenia.