Abstract: Objective The aim of this study was to investigate the skeletal muscle mass (SMM) changes in patients with non-alcoholic fatty liver diseases (NAFLD). Methods A total of 7467 individuals were encountered in the Health Management Center, First Affiliated Hospital, Nanjing Medical University between January 2020 and June 2021, and the physical examination were carried out. The abdominal ultrasonography showed the NAFLD in 3385 cases and other 4082 persons served as the control. The NAFLD fibrosis score (NFS) greater than 0.676 was found in 39 cases with advanced liver fibrosis (ALF), in 2591 cases without liver fibrosis and in 755 cases with non-advanced liver fibrosis. The SMM index (SMI) was calculated as follows: the appendicular skeletal muscle mass/ body weight. Results The SMI in patients with NAFLD was (38.8±3.3)%, significantly lower than [(40.7±3.3)%, P<0.01] in the control; the Logistic regression analysis showed that the SMI was the independent impacting factor for NAFLD occurrence as corrected by metabolic factors (OR=0.719, 95%CI 0.694-0.745, P<0.001); the 7467 individuals were divided into three groups by SMI tertiary, the analysis showed corrected by age, blood sugar and fat that individuals with low and middle SMI had 1.482 times and 2.328 times high tendency of risk for NAFLD compared to those with high SMI as the reference, and the incidences of NAFLD in individuals with low, middle and high SMI were 53.5%, 46.8% and 35.8%(P<0.05); the SMI in patients with ALF was (37.6±3.6)%, significantly lower than in with non-advanced or without liver fibrosis [(38.1±3.5)% or (39.0±3.2)%, P<0.01]; the patients with NAFLD were divided into three groups by SMI tertiary as with low SMI in 1129 cases, middle in 1128 cases and high in 1128 cases, and the analysis showed that the incidences of ALF in patients with low, middle and high SMI were 1.9%, 1.0% and 0.6%(P<0.05), of without ALF were 26.6%, 22.2% and 18.0%(P<0.05), and of without liver fibrosis were 71.5%, 76.8% and 81.4%(P<0.05). Conclusion The decreased SMM is common in patients with NAFLD and might be related to ALF, which needs further investigation.

Key words: Non-alcoholic fatty liver diseases, Skeletal muscle mass, Advanced liver fibrosis