Nonalcoholic fatty liver disease and sarcopenia in a Western population (NHANES III): The importance of sarcopenia definition.

BACKGROUND: Recent epidemiological studies have shown that sarcopenia is associated with non-alcoholic fatty liver disease (NAFLD) and advanced fibrosis in an Asian population. We investigated whether NAFLD is associated with a higher risk of sarcopenia using a different definition in elderly patients.

METHODS: A population-based cross-sectional survey of US patients was conducted, involving 2551 participants aged 60-75 years. NAFLD was measured by ultrasound. Sarcopenia was defined by both a low muscle mass and poor muscle function. In addition, the skeletal muscle index (SMI) was calculated as the absolute muscle mass (kilograms) divided by height2 (meters) or total body mass (kilograms). A multivariable logistic regression was conducted to estimate the relationship between sarcopenia and NAFLD in the elderly.

RESULTS: After adjusting for age, sex, and race/ethnicity, severe hepatic steatosis was associated with a decreased risk of sarcopenia as defined by the height-adjusted SMI (odds ratio (OR) 0.63; 95% confidence interval (CI) 0.46-0.87). In contrast, severe hepatic steatosis was associated with an increased risk of sarcopenia as defined by the weight-adjusted SMI (OR 1.73; 95% CI 1.31-2.28). These significant associations remained after further adjustments for other potential confounding variables.

CONCLUSIONS: NAFLD is associated with a lower risk of sarcopenia when using the height-adjusted SMI. In contrast, it showed the opposite result when using the weight-adjusted SMI. The definition of sarcopenia may be an important factor when examining its relationship with NAFLD.