Age is a Negative, and Visceral Fat Accumulation is a Positive, Contributor to Hepatic Steatosis, Regardless of the Fibrosis Progression in Non-alcoholic Fatty Liver Disease

Abstract

AIM: Because aging affects fat distribution, we evaluated age-related changes in the deposition of fat in the liver, compared to the visceral and intramuscular fat compartments, in non-alcoholic fatty liver disease (NAFLD). A “burn-out” phenomenon of hepatic steatosis is associated with progression of fibrosis in NAFLD. We clarified the effect of progression of fibrosis on steatosis.

METHODS: Sixty patients clinically diagnosed as NAFLD, of whom 28 were confirmed histologically, and 26 normal subjects were examined. Platelet counts and serum concentrations of alanine aminotransferase (ALT), ferritin and hyaluronic acid (HA) were measured. Hepatic steatosis, visceral fat area (VFA), subcutaneous fat area (SFA) and the multifidus muscle/subcutaneous fat attenuation (MM/F) ratio were evaluated by computed tomography. The ratio of hepatic fat deposition to VFA, defined as the liver-viscera (LV) index, quantified the ratio of hepatic steatosis to visceral adiposity.

RESULTS: In NAFLD patients, univariate analysis showed the degree of steatosis was correlated positively with VFA, SFA and ALT, and negatively with age, MM/F ratio and HA. Age and VFA retained significance in multivariate analysis. Age was negatively correlated with the LV index. Age was negatively correlated with steatosis and the LV index in 17 patients with fibrosis stage 0 or 1 but not in normal subjects.

CONCLUSION: Age is a negative, and visceral fat accumulation is a positive, independent contributor to steatosis. Hepatic fibrosis is negatively correlated with steatosis but not an independent contributor. Fat is distributed less in the liver, relative to the visceral compartment, with increasing age.