FNDC5 and sarcopenia: Multivariable regression analysis including L3 SMI, body mass index (BMI), very-low-density lipoprotein (VLDL)-cholesterol, aspartate aminotransferase (AST), adiponectin, and irisin levels showed that L3 SMI (odds ratio [OR] = 0.915, p = 0.023), adiponectin levels (OR = 1.074, p = 0.014), irisin levels (OR = 0.993, p < 0.001) and BMI (OR = 0.456, p = 0.004) were independently associated with sarcopenia.