BACKGROUND:Osteoporosis is often accompanied by sarcopenia and an increased risk of fractures from falls.Recent studies have indicated a close relationship between lipid metabolism and sarcopenia.Abnormal lipid metabolism may directly impact muscle physiological function and metabolism. OBJECTIVE:To investigate the relationship between lipid metabolism and sarcopenia and evaluate their causal relationship using Mendelian randomization. METHODS:Mendelian randomization was used to explore the causal relationship between low-density lipoprotein cholesterol,high-density lipoprotein cholesterol,triglycerides,and muscle mass.Research data from genome-wide association studies were used and a sensitivity analysis was conducted to verify the reliability of the results.Approximate indicators of muscle mass,including trunk lean mass and appendicular lean mass,were used as outcome measures. RESULTS AND CONCLUSION:The study found a negative correlation of low-density lipoprotein cholesterol and triglycerides with muscle mass,while no correlation was observed between high-density lipoprotein cholesterol and muscle mass.The results of the sensitivity analysis indicated a robust causal relationship.Using Mendelian randomization,this study provides evidence of a causal relationship between low-density lipoprotein cholesterol and triglycerides and muscle mass.This finding deepens our understanding of the effects of lipids on sarcopenia and has important clinical implications for the prevention and treatment of sarcopenia and osteoporosis.