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World J Hepatol. Jul 27, 2021; 13(7): 763-773
Published online Jul 27, 2021. doi: 10.4254/wjh.v13.i7.763
Racial differences in prevalence and severity of non-alcoholic fatty liver disease
Maurizio Bonacini, Farah Kassamali, Swathi Kari, Nieves Lopez Barrera, Mohamed Kohla
Maurizio Bonacini, Department of Gastroenterology and Hepatology, California Pacific Medical Center, California Pacific Medical Center, San Francisco, CA 94115, United States
Farah Kassamali, Department of Gastroenterology and Hepatology, California Pacific Medical Center, San Francisco, CA 94115, United States
Swathi Kari, Department of Internal Medicine, St. Mary's medical Center, San Francisco, CA 94117, United States
Nieves Lopez Barrera, Quest Clinical Research, San Francisco, CA 94115, United States
Mohamed Kohla, Department of Hepatology, National Liver Institute, Menoufiya University, Shibin Al Kom 32511, Menoufiya, Egypt
Author contributions: Bonacini M and Kassamali F did the main literature review; all authors reviewed and rewrote the manuscript to address the reviewers questions.
Conflict-of-interest statement: Authors report no conflict-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: http://creativecommons.org/Licenses/by-nc/4.0/
Corresponding author: Maurizio Bonacini, AGAF, MD, Associate Professor, Staff Physician, Department of Gastroenterology and Hepatology, California Pacific Medical Center, California Pacific Medical Center, 2333 Buchanan Street, San Francisco, CA 94115, United States. bonacim08@gmail.com
Received: January 4, 2021
Peer-review started: January 4, 2021
First decision: January 25, 2021
Revised: April 8, 2021
Accepted: July 7, 2021
Article in press: July 7, 2021
Published online: July 27, 2021
Processing time: 200 Days and 5.5 Hours
Abstract

The aim of this review is to assess the evidence regarding racial differences in the prevalence and severity of nonalcoholic fatty liver disease (NAFLD). We reviewed the published literature that reported prevalence, severity, and genetic associations of NAFLD in different ethnic groups. The metabolic syndrome (MetS) has been associated with NAFLD, but each component of the MetS is present in various races in different percentages and their effect on NAFLD appears to be dissimilar. An elevated triglyceride (TG) level seems to have the strongest association with NAFLD. The latter is more prevalent in Hispanic patients; Blacks have lower TG levels and a lower NAFLD prevalence, compared to Caucasians or Hispanics. The severity of liver fibrosis is lower in some, but not all biopsy-based studies of Black patients. No study has evaluated the severity of liver disease controlling for the individual components of MetS, especially TG. Important racial differences in the prevalence of selected genetic polymorphisms, particularly PNPLA-3 and MBOAT7 have been documented, together with their effects on the prevalence of liver steatosis and fibrosis. Data on overall and liver mortality have found no significant differences according to race/ethnicity, with the possible exception of one paper reporting lower cirrhosis mortality in Black patients. We conclude that NAFLD is more prevalent in Hispanics and less in Blacks. This is supported by differences in key genetic polymorphisms associated with hepatic fat storage. However, there is presently insufficient evidence to firmly conclude that race, per se, plays a role in the development of liver fibrosis and its complications. Further studies, appropriately controlled for diet, exercise, and individual MetS parameters are needed.

Keywords: Race; Ethnicity; Nonalcoholic fatty liver disease; Fatty liver disease; Metabolic syndrome

Core Tip: Nonalcoholic fatty liver disease is one of the most common diagnoses made in a Gastroenterology practice. The prevalence and severity of nonalcoholic fatty liver disease in different ethnic groups need to be evaluated by controlling for the individual variables of the metabolic syndrome. This is because these variables are different in various ethnicities.