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World J Gastrointest Pathophysiol. Aug 15, 2017; 8(3): 100-107
Published online Aug 15, 2017. doi: 10.4291/wjgp.v8.i3.100
Fatty liver without a large “belly”: Magnified review of non-alcoholic fatty liver disease in non-obese patients
Mohamad H Yousef, Alhareth Al Juboori, Abdulmajeed A Albarrak, Jamal A Ibdah, Veysel Tahan
Mohamad H Yousef, Alhareth Al Juboori, Abdulmajeed A Albarrak, Jamal A Ibdah, Veysel Tahan, Division of Gastroenterology and Hepatology, University of Missouri, Columbia, MO 65212, United States
Author contributions: All authors contributed to the acquisition of data, writing, and revision of this manuscript.
Conflict-of-interest statement: All the authors have no conflicts of interests to declare.
Open-Access: This article is an open-access article which was selected by an in-house editor and fully peer-reviewed by external reviewers. It is distributed in accordance with the Creative Commons Attribution Non Commercial (CC BY-NC 4.0) license, which permits others to distribute, remix, adapt, build upon this work non-commercially, and license their derivative works on different terms, provided the original work is properly cited and the use is non-commercial. See: http://creativecommons.org/licenses/by-nc/4.0/
Correspondence to: Veysel Tahan, MD, FACG, FEBGH, Professor (As) of Medicine, Division of Gastroenterology and Hepatology, University of Missouri, 1 Hospital Dr, Columbia, MO 65212, United States. tahanv@health.missouri.edu
Telephone: +1-573-8846044 Fax: +1-573-8844595
Received: March 19, 2017
Peer-review started: March 20, 2017
First decision: May 9, 2017
Revised: May 22, 2017
Accepted: June 19, 2017
Article in press: June 20, 2017
Published online: August 15, 2017
Processing time: 147 Days and 18.3 Hours
Abstract

Nonalcoholic fatty liver disease (NAFLD) is well described as a common cause of chronic liver disease, mostly in the obese population. It refers to a spectrum of chronic liver disease that starts with simple steatosis than progresses to nonalcoholic steatohepatitis and cirrhosis in patients without significant alcohol consumption. NAFLD in the non-obese population has been increasingly reported and studied recently. The pathogenesis of nonobese NAFLD is poorly understood and is related to genetic predisposition, most notably patatin-like phospholipase domain-containing 33 G allele polymorphism that leads to intrahepatic triglyceride accumulation and insulin resistance. Non-obese NAFLD is associated with components of metabolic syndrome and, especially, visceral obesity which seems to be an important etiological factor in this group. Dietary factors and, specifically, a high fructose diet seem to play a role. Cardiovascular events remain the main cause of mortality and morbidity in NAFLD, including in the non-obese population. There is not enough data regarding treatment in non-obese NAFLD patients, but similar to NAFLD in obese subjects, lifestyle changes that include dietary modification, physical activity, and weight loss remain the mainstay of treatment.

Keywords: Nonobese; Nonalcoholic fatty liver disease; Hepatic steatosis; Nonalcoholic steatohepatitis; Genetic

Core tip: Nonobese nonalcoholic fatty liver disease (NAFLD) is likely a different entity than obese NAFLD, with its unique genetic predisposition. NAFLD in the nonobese population has been increasingly reported and studied recently. It is associated with components of metabolic syndrome. Interestingly, even though non-obese NAFLD patients have normal weight ranges, weight loss remains the mainstay treatment and was found to be beneficial. Diagnosis and treatment are similar to the obese non-alcoholic fatty liver disease. Further research is needed for better understanding of the genetic and environmental factors affecting the course of this specific entity.