Nonalcoholic fatty liver disease (NAFLD) is a primary contributor to hepatocellular carcinoma (HCC)/liver cirrhosis (LC), affecting ∼30 % of the global population. Its incidence is rising parallel to increasing prevalences of metabolic syndrome and obesity [1,2]. Although obesity primarily contributes to NAFLD, approximately 3∼40 % of NAFLD patients are lean and 20 % in lean population have NAFLD [3]. Currently, lean NAFLD has been defined using a body mass index (BMI) threshold of <23 kg/m² for Asians and <25 kg/m² for other ethnicities.
