Risk of nonalcoholic steatohepatitis and fibrosis in patients with nonalcoholic fatty liver disease and low visceral adiposity

Background & Aims: Increased visceral adiposity is considered the hallmark of the metabolic syndrome, whose hepatic manifestation is nonalcoholic fatty liver disease (NAFLD), although a subset of patients does not have visceral obesity. Our study aimed to compare metabolic alterations and liver damage in patients with NAFLD with and without visceral obesity. Methods: Four hundred and thirty one consecutive patients with liver biopsy-confirmed NAFLD were divided in three groups according to waist circumference, the simplest surrogate marker of visceral obesity. One hundred and thirty three patients (31%) had a waist circumference ≤94 (males) and ≤80 cm (females) (group A), 157 (36%) between 94 and 102, and 80 and 88 (B), and the remaining 141 (33%) had values higher than 102 and 88 cm (C). Results: Significant trends for older age, higher prevalence of female gender, lower HDL, higher triglycerides, altered glucose metabolism, hypertension, and metabolic syndrome were observed with increasing visceral adiposity. In contrast, non-alcoholic steatohepatitis (NASH) detected in 55% and 72% of patients with normal and increased waist circumference, respectively, and the presence of fibrosis ≥2 were not associated with visceral adiposity. Alanine aminotransferase (ALT), ferritin, HOMA-IR >4, and severe steatosis were independently associated with NASH, whereas ferritin and impaired glucose tolerance were associated with fibrosis ≥2. Conclusions: Patients with normal waist circumference, despite milder metabolic alterations, may have NASH and are at risk of developing fibrosis, suggesting that once NAFLD is present, visceral obesity is not a major determinant of liver damage severity.