Relationship Between Body Composition and the Histology of Non-alcoholic Fatty Liver Disease: A Cross-sectional Study

BACKGROUND Causes of non-alcoholic fatty liver disease and its progression include visceral fat accumulation and loss of muscle mass; however, which of the two phenomena is more critical is unclear. Therefore, we intended to examine the relationship between body composition and non-alcoholic fatty liver disease progression as indicated by fibrosis and the non-alcoholic fatty liver disease activity score. METHODS This cross-sectional study comprised 149 patients (55 men; age, 20-76 years) treated for non-alcoholic fatty liver disease between December 2010 and January 2020. Body composition measurements, histological examinations of liver samples, and comprehensive blood chemistry tests were performed. The relationship between body composition and non-alcoholic fatty liver disease histology findings was analyzed using the logistic regression model. RESULTS Fibrosis was significantly and inversely correlated with muscle mass and appendicular skeletal muscle mass and significantly and positively correlated with fat mass, fat mass/height squared, visceral fat area, and waist-hip ratio (P < 0.05). After adjustment for sex, blood chemistry measurements, and body composition indices, fibrosis remained associated with appendicular skeletal muscle mass, fat mass, fat mass/height squared, and visceral fat area (P < 0.05). Non-alcoholic fatty liver disease activity score ≥ 5 significantly correlated with fat mass and fat mass/height squared in a univariate but not multivariate analysis. CONCLUSIONS Fibrosis in non-alcoholic fatty liver disease, an indicator of unfavorable long-term outcomes, is associated with more indices of fat mass than of those of muscle mass. Hence, fat mass should be controlled to prevent non-alcoholic fatty liver disease progression.