Sex influences the association between appendicular skeletal muscle mass to visceral fat area ratio and nonalcoholic steatohepatitis in patients with biopsy-proven NAFLD

Background: sarcopenic obesity is regarded as a risky factor for the progression and development of non-alcoholic fatty liver disease (NAFLD). Since male sex is a risk factor for NAFLD and skeletal muscle mass markedly varies between the sexes, we examined whether sex influences the association between appendicular skeletal muscle mass to visceral fat area ratio (SVR), i.e., an index of skeletal muscle mass combined with abdominal obesity, and the histological severity of NAFLD. Methods: SVR was measured by bioelectrical impedance in a cohort of 613(M/F=443/170) Chinese middle-aged individuals with biopsy-proven NAFLD. Multivariable logistic regression as well as subgroup analyses were used to test the association between SVR and the severity of NAFLD (i.e., nonalcoholic steatohepatitis (NASH) or NASH with presence of any stage of liver fibrosis). NASH was identified by a NAFLD activity score≥5, with a minimum score of 1 for each of its categories. Presence of fibrosis was classified as having a histological stage ≥1. Results: SVR was inversely associated with NASH in men (adjusted-odds ratio 0.62; 95%CI 0.42-0.92, P=0.017 for NASH, adjusted-odds ratio 0.65; 95%CI 0.43-0.99, P=0.043 for NASH with presence of fibrosis); but not in women 1.47 (0.76, 2.83), P=0.25 for NASH, and 1.45 (0.74, 2.83), P=0.28 for NASH with presence of fibrosis. There was a significant interaction for sex and SVR (Pinteraction=0.017 for NASH and Pinteraction=0.033 for NASH with presence of fibrosis). Conclusion: Our findings show that lower skeletal muscle mass combined with 87 abdominal obesity is strongly associated with the presence of NASH only in men.