title: Lean non-alcoholic fatty liver disease (Lean-NAFLD): a major cause of cryptogenic liver disease.
abstract: OBJECTIVE
  Non-alcoholic fatty liver disease (NAFLD) is strongly associated to obesity and type 2 diabetes, but may occur in the absence of these factors. Based on a large series of liver biopsies, we have evaluated the clinical, biochemical, metabolic and pathological characteristics of a new entity, which we refer to as "lean-NAFLD".
  
  
  METHODS
  Among 1,777 patients, who underwent liver biopsy for chronic liver disease, Lean-NAFLD, defined as patients with NAFLD without obesity (BMI < 30 kg/m2) and without diabetes was found in 50 of them (2.8%), being the most frequent cause (38%) of cryptogenic liver disease. Thirty-one patients from the Lean-NAFLD group were compared to 48 Obese-NAFLD patients diagnosed during the same period and 8 healthy control patients. Insulin resistance was determined using the homeostasis model assessment method.
  
  
  RESULTS
  In the Lean-NAFLD group as compared to the obese-NAFLD group, patients were younger : median 40 vs. 49 years, p = 0.047, with male predominance: 71 vs. 46%, p = 0.037. Fasting glucose and HbA1c were lower, as was insulin sensitivity: 1.7 vs. 3.0, p = 0.049. Blood pressure was significantly lower (p = 0.001) while triglycerides and HDL-cholesterol were similar. Although there was less inflammation (p = 0.038) and fibrosis (p = 0.029), non-alcoholic steatohepatitis and fibrosis were present in 61% and 55% of the Lean-NAFLD group, respectively. Compared to healthy controls, Lean-NAFLD were less insulin sensitive, with a insulin sensitivity index of 59 vs. 110 (p = 0.015), and more hypertriglyceridemic (p = 0.003).
  
  
  CONCLUSIONS
  Lean-NAFLD is a new unrecognized clinicopathological entity, a frequent cause of cryptogenic liver disease.
authors: Department of Gastroenterology and Hepato-Pancreatology, Erasme Hospital, Université Libre de Bruxelles, Brussels, Belgium. bertrand.vos@ulb.ac.be
authors: Bertrand
authors: B
authors: Vos
authors: Christophe
authors: C
authors: Moreno
authors: Nathalie
authors: N
authors: Nagy
authors: Françoise
authors: F
authors: Féry
authors: Miriam
authors: M
authors: Cnop
authors: Pierre
authors: P
authors: Vereerstraeten
authors: Jacques
authors: J
authors: Devière
authors: Michael
authors: M
authors: Adler
mesh_terms: D000328:Adult; D000368:Aged; D001706:Biopsy; D001835:Body Weight; D005234:Fatty Liver / Q000150:complications* / Q000473:pathology*; D005260:Female; D006521:Hepatitis, Chronic / Q000209:etiology* / Q000473:pathology*; D006801:Humans; D008099:Liver / Q000473:pathology*; D008297:Male; D008875:Middle Aged; D065626:Non-alcoholic Fatty Liver Disease