Waist circumference correlates with hepatic fat accumulation in male Japanese patients with non-alcoholic fatty liver disease, but not in females

Background and Aim: Abdominal obesity, a component of metabolic syndrome, is a major risk factor for non-alcoholic fatty liver disease (NAFLD). In recent worldwide definitions of metabolic syndrome, waist measurement has been proposed as a simple and useful estimate of abdominal obesity, taking into account gender differences in waist circumference. The present cross-sectional study investigated the correlation of hepatic fat accumulation and waist circumference in Japanese NAFLD patients to determine if there are gender differences in this relationship. Methods: Consecutive patients (n = 2111) who had at least one of two criteria for liver disease (alanine aminotransferase [ALT] level >30 IU/mL and aspartate aminotransferase [AST]/ALT ratio <1) underwent abdominal ultrasonography. Patients positive for hepatitis B virus, hepatitis C virus or autoimmune antibodies and whose alcohol intake was >20 g/day were excluded. Patients with NAFLD underwent abdominal computed tomography. Hepatic fat accumulation was estimated by liver/spleen attenuation ratio (L/S ratio) and visceral adipose accumulation was measured as visceral fat area (VFA) at the umbilical level. Results: Of the 221 NAFLD patients, 103 were females. In males, the relationship between L/S ratio and waist circumference was negative (r = -0.356, P < 0.01), and there was no correlation in the female group. The relationship between L/S ratio and VFA was negative in both groups (males: r = -0.269, P < 0.01; females: r = -0.319, P < 0.01). Subcutaneous fat area/total fat area ratio at the umbilical level was larger in females than in males (P < 0.01). Conclusions: In NAFLD patients, waist measurement is more susceptible to gender differences than VFA.