Copyright ©The Author(s) 2021. Published by Baishideng Publishing Group Inc. All rights reserved.
World J Hepatol. Jan 27, 2021; 13(1): 80-93
Published online Jan 27, 2021. doi: 10.4254/wjh.v13.i1.80
Shifting perspectives – interplay between non-alcoholic fatty liver disease and insulin resistance in lean individuals
Ines Bilic-Curcic, Maja Cigrovski Berkovic, Lucija Virovic-Jukic, Anna Mrzljak
Ines Bilic-Curcic, Department of Pharmacology, Faculty of Medicine, University of J. J. Strossmayer Osijek, Osijek 31000, Croatia
Ines Bilic-Curcic, Clinical Hospital Center Osijek, Osijek 31000, Croatia
Maja Cigrovski Berkovic, Department of Kinesiological Anthropology and Methodology, Faculty of Kinesiology, University of Zagreb, Zagreb 10000, Croatia
Maja Cigrovski Berkovic, Clinical Hospital Dubrava, Zagreb 10000, Croatia
Lucija Virovic-Jukic, Department of Medicine, Division of Gastroenterology and Hepatology, Sisters of Charity University Hospital, Zagreb 10000, Croatia
Lucija Virovic-Jukic, Anna Mrzljak, School of Medicine, University of Zagreb, Zagreb 10000, Croatia
Anna Mrzljak, Department of Medicine, Merkur University Hospital, Zagreb 10000, Croatia
Author contributions: Bilic-Curcic I made contributions to the conception and design of the study, involved in drafting and revising the manuscript critically; Cigrovski Berkovic M, Virovic-Jukic L and Mrzljak A were involved in collecting the data, and drafting and writing the manuscript; All authors read and approved the final manuscript.
Conflict-of-interest statement: No potential conflicts of interest.
Open-Access: This article is an open-access article that was selected by an in-house editor and fully peer-reviewed by external reviewers. It is distributed in accordance with the Creative Commons Attribution NonCommercial (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:
Corresponding author: Anna Mrzljak, FEBG, MD, PhD, Associate Professor, Department of Medicine, Merkur University Hospital, Zajčeva 19, Zagreb 10000, Croatia.
Received: June 13, 2020
Peer-review started: June 13, 2020
First decision: October 21, 2020
Revised: October 22, 2020
Accepted: November 17, 2020
Article in press: November 17, 2020
Published online: January 27, 2021

Non-alcoholic fatty liver disease (NAFLD) has become a significant public health burden affecting not only obese individuals but also people with normal weight. As opposed to previous beliefs, this particular subset of patients has an increased risk of all-cause mortality and worse outcomes than their obese counterparts. The development of NAFLD in lean subjects seems to be interconnected with metabolic phenotype, precisely visceral fat tissue, sarcopenia, and insulin resistance. Here, we summarize available data focusing on the co-dependent relationship between metabolic phenotype, insulin resistance, and development of NAFLD in lean individuals, suggesting more appropriate tools for measuring body fat distribution for the screening of patients at risk.

Keywords: Non-alcoholic fatty liver disease, Metabolic phenotype, Lean individuals, Insulin resistance, Visceral fat tissue, Sarcopenia

Core Tip: The prevalence of non-alcoholic fatty liver disease among non-obese (overweight or lean) individuals seems to be much higher than previously reported, affecting almost 20% of the non-obese population. Non-alcoholic fatty liver disease is no longer considered solely an obesity-related disorder since non-obese individuals participate significantly in this entity. The metabolic phenotype is the key role-player in the development of non-alcoholic fatty liver disease in lean individuals. The detection of lean patients with non-alcoholic fatty liver disease is particularly challenging since the body-mass index is not a good indicator of metabolic health.