The association between appendicular skeletal muscle index and liver steatosis and fibrosis: A cross-sectional study

Skeletal muscle index (SMI) is a measure for evaluating skeletal muscle status. However, its specific association with liver steatosis and fibrosis remains unclear. The aim of this study was to investigate the association between SMI and liver steatosis and fibrosis.

We conducted a cross-sectional study with a random selection of 328 participants over the age of 18, with no history of alcohol consumption or liver disease, from a nutrition clinic in Iran. Waist circumference (WC) and hip circumference (HC) were measured using a tape measure according to standards. Total fat mass, SMI, and other body composition parameters were obtained via bioelectrical impedance analysis. Liver status was assessed in all participants using elastography (FibroScan®).

The participants included 64.0% males and 36.0% females, with a median age of 41 (IQR:14) years. After adjusting for confounders, SMI had no significant association with liver steatosis (P=0.647). Indeed, body mass index (BMI) (P=0.028), WC (P=0.038), and HC (P=0.007) were the significant predictors of liver steatosis. Conversely, each unit increase in SMI value decreased the chance of liver fibrosis by 48% after controlling the confounders (aOR=0.519, 95%CI: 0.283-0.951, P=0.034). Additionally, BMI (P=001), WC (P=0.006), and HC (P=0.026) were other significant predictors of liver fibrosis.

In conclusion, while a higher SMI did not mitigate obesity-linked liver steatosis risk, it independently lowered the odds of fibrosis. Furthermore, increased waist circumference was a stronger predictor of both steatosis and fibrosis than increased trunk fat mass.