Background: Non-alcoholic fatty liver disease (NAFLD) recently became a leading liver disease that threatens health worldwide. Low muscle strength, obesity, insulin resistance, and metabolic syndrome are recognized key factors for NAFLD. However, the impact of low muscle strength itself in different metabolic conditions has not been widely studied.
Methods: A cross-sectional analysis was performed of a sample of 5,427 participants from the 2019 Korea National Health and Nutrition Examination Survey. Relative handgrip strength (rHGS, defined as handgrip strength/body mass index) was used to assess muscle strength. The cut-off values for a low rHGS were 1.405 for men and 0.850 for women. NAFLD was diagnosed if the Hepatic Steatosis Index was >36. Participants were stratified according to insulin resistance, metabolic syndrome, and central obesity for the subgroup analyses.
Results: Complex sample multivariate logistic regression analysis revealed a significant association between low muscle strength and NAFLD after the adjustment for other confounders (odds ratio [OR], 1.92; P<0.001). In the insulin resistance, metabolic syndrome, and central obesity subgroups, a significant association between low muscle strength and NAFLD remained (OR, 1.66-4.19 depending on subgroup; all P<0.05), whereas it did not in the no central obesity group.
Conclusion: This study demonstrated that low muscle strength is correlated with a risk of NAFLD. This relationship was independent of insulin resistance and metabolic syndrome but was dependent on the presence of central obesity.
Keywords: Insulin Resistance; Metabolic Syndrome; Muscle Strength; Non-alcoholic Fatty Liver Disease; Sarcopenia.