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Copyright ©The Author(s) 2016. Published by Baishideng Publishing Group Inc. All rights reserved.
World J Gastroenterol. Sep 21, 2016; 22(35): 7868-7881
Published online Sep 21, 2016. doi: 10.3748/wjg.v22.i35.7868
Interaction of obesity and inflammatory bowel disease
Jason W Harper, Timothy L Zisman
Jason W Harper, Department of Gastroenterology, Swedish Medical Center, Seattle, WA 98195, United States
Timothy L Zisman, Inflammatory Bowel Disease Program, Division of Gastroenterology, University of Washington Medical Center, Seattle, WA 98195, United States
Author contributions: Harper JW and Zisman TL contributed equally to the preparation of this manuscript, including review of the literature, drafting of the manuscript, critical revision and approval of the final version to be published.
Conflict-of-interest statement: No conflict of interest.
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: Timothy L Zisman, MD, MPH, Associate Professor of Medicine, Inflammatory Bowel Disease Program, Division of Gastroenterology, University of Washington Medical Center, 1959 NE Pacific St., Box 356424, Seattle, WA 98195, United States. tzisman@medicine.washington.edu
Telephone: +1-206-6857174 Fax: +1-206-6858684
Received: March 28, 2016
Peer-review started: April 2, 2016
First decision: May 12, 2016
Revised: June 10, 2016
Accepted: August 5, 2016
Article in press: August 5, 2016
Published online: September 21, 2016
Processing time: 169 Days and 19.3 Hours
Abstract

Inflammatory bowel disease (IBD) is a chronic inflammatory condition of unknown etiology that is thought to result from a combination of genetic, immunologic and environmental factors. The incidence of IBD has been increasing in recent decades, especially in developing and developed nations, and this is hypothesized to be in part related to the change in dietary and lifestyle factors associated with modernization. The prevalence of obesity has risen in parallel with the rise in IBD, suggesting a possible shared environmental link between these two conditions. Studies have shown that obesity impacts disease development and response to therapy in patients with IBD and other autoimmune conditions. The observation that adipose tissue produces pro-inflammatory adipokines provides a potential mechanism for the observed epidemiologic links between obesity and IBD, and this has developed into an active area of investigative inquiry. Additionally, emerging evidence highlights a role for the intestinal microbiota in the development of both obesity and IBD, representing another potential mechanistic connection between the two conditions. In this review we discuss the epidemiology of obesity and IBD, possible pathophysiologic links, and the clinical impact of obesity on IBD disease course and implications for management.

Keywords: Inflammatory bowel disease; Crohn’s disease; Ulcerative colitis; Obesity; Body mass index

Core tip: Epidemiologic studies have shown a parallel rise in the prevalence of obesity and immune-mediated conditions, including inflammatory bowel disease (IBD). This association may be related to share dietary or environmental exposures that exert their effect through changes in the intestinal microbiota. Several lines of evidence demonstrate that obesity is a pro-inflammatory condition that impacts the incidence, disease course and response to therapy in patients with IBD. Exploring the mechanisms of interaction between obesity and IBD advances our understanding of IBD and opens up a potential role for weight loss and weight maintenance strategies in the management of IBD.