Impact of skeletal muscle mass evaluating methods on severity of metabolic associated fatty liver disease in nonelderly adults.

The study aimed to explore the relationships of skeletal muscle mass with disease severity in MAFLD patients with different methods. Consecutive subjects undergoing bioelectrical impedance analysis were included. The steatosis grade and liver fibrosis were evaluated by magnetic resonance imaging-derived proton density fat fraction and two-dimensional shear wave elastography. The appendicular skeletal muscle mass (ASM) was adjusted by height2 (ASM/H2 ), weight (ASM/W) and body mass index (ASM/BMI). Overall, 2223 subjects (50.5%, MAFLD; 46.9%, male) were included, and the mean age was 37.4 ± 10.6 years. In multivariate logistic regression analysis, the subjects with the lowest quartile (Q1) of ASM/W or ASM/BMI had higher risk ratios for MAFLD [ORs (95% CI) in male: 2.57 (1.35-4.89), 2.11(1.22-3.64); in female: 4.85 (2.33-10.01), 4.81 (2.52-9.16), all P <0.05, all for Q1 vs Q4]. The MAFLD patients with lower quartiles of ASM/W had the higher risk ORs for insulin resistance (IR), both in male and female [2.14 (1.16-3.97), 4.26 (1.29-14.02) for Q4 vs. Q1, both P <0.05]. While the significant ORs were not observed when ASM/H2 and ASM/BMI was used. There were significant dose-dependent associations between decreased ASM/W as well as ASM/BMI and moderate-severe steatosis [2.85(1.54-5.29), 1.90(1.09-3.31), both P <0.05] in male MAFLD patients. There was no such association in male MAFLD patients with ASM/H2 or in female MAFLD with three of methods. In conclusion, ASM/W is superior to ASM/H2 and ASM/BMI in predicting the degree of MAFLD. A lower ASM/W is associated with IR and moderate-severe steatosis in non-elderly male MAFLD.