Abstract
BACKGROUND: The association of myosteatosis measured using visual muscular quality map in computed tomography (CT) with nonalcoholic fatty liver disease (NAFLD), its severity, and fibrosis was analyzed in a large population. METHODS: Subjects (n=13,452) with abdominal CT between 2012 and 2013 were measured total abdominal muscle area (TAMA) at L3 level. TAMA was segmented into intramuscular adipose tissue and skeletal muscle area (SMA), which was further classified into normal attenuation muscle area (NAMA) and low attenuation muscle area (LAMA). The following variables were adopted as indicators of myosteatosis: SMA/body mass index (BMI), NAMA/BMI, NAMA/TAMA, and LAMA/BMI. NAFLD and its severity were assessed by ultrasonography, and liver fibrosis was measured by calculating the NAFLD fibrosis score (NFS) and fibrosis-4 index (FIB-4) scores. RESULTS: According to multiple logistic regression analyses, as quartiles of SMA/BMI, NAMA/BMI, and NAMA/TAMA increased, the odds ratios (ORs) for NAFLD decreased in each sex (P for trend <0.001 for all). The ORs of moderate/severe NAFLD were significantly higher in the Q1 group than in the Q4 group for SMA/BMI, NAMA/BMI, and NAMA/TAMA in men. The ORs of intermediate/high liver fibrosis scores assessed by NFS and FIB-4 scores increased linearly with decreasing quartiles for SMA/BMI, NAMA/BMI, and NAMA/TAMA in each sex (P for trend <0.001 for all). Conversely, the risk for NAFLD and fibrosis were positively associated with LAMA/BMI quartiles in each sex (P for trend <0.001 for all). CONCLUSION: A higher proportion of good quality muscle was associated with lower risks of NAFLD and fibrosis.