Sarcopenia and fatty liver disease.

Non-alcoholic fatty liver disease (NAFLD) is the most common liver disease which may progress to non-alcoholic steatohepatitis. The prevalence of sarcopenia, which is the loss of muscle mass and strength, is increasing in the aging society. Recent studies reported the relationship between NAFLD and sarcopenia. The skeletal muscle is the primary organ for glucose disposal. Loss of muscle mass can cause insulin resistance, which is an important risk factor for NAFLD. Moreover, obesity, chronic low-grade inflammation, vitamin D deficiency, physical inactivity, hepatokines, and myokines might be involved in the pathophysiologic mechanism of sarcopenia and NAFLD. Although most of the previous studies have demonstrated the positive correlation between sarcopenia and NAFLD, the difference in diagnostic methods of sarcopenia and NAFLD leads to difficulties in interpretation and application. This review discusses the concept and diagnosis of sarcopenia and NAFLD, common pathophysiology, and clinical studies linking sarcopenia to NAFLD. The presentation of the association between sarcopenia and NAFLD may provide an opportunity to prevent the deterioration of fatty liver disease.