Systematic Reviews
Copyright ©The Author(s) 2018. Published by Baishideng Publishing Group Inc. All rights reserved.
World J Gastroenterol. Jan 21, 2018; 24(3): 424-437
Published online Jan 21, 2018. doi: 10.3748/wjg.v24.i3.424
Epidemiology of inflammatory bowel disease in racial and ethnic migrant groups
Ravi Misra, Omar Faiz, Pia Munkholm, Johan Burisch, Naila Arebi
Ravi Misra, Naila Arebi, Department of Gastroenterology, St. Marks Academic Institute, London HA1 3UJ, United Kingdom
Omar Faiz, Surgical Epidemiology, Trials and Outcome Centre, St. Marks Academic Institute, London HA1 3UJ, United Kingdom
Pia Munkholm, Johan Burisch, Department of Gastroenterology, North Zealand University Hospital, Frederikssund Frederikssundsvej 30, Denmark
Author contributions: Misra R and Arebi N were responsible for the conception and design of the study, and for revising it critically for important intellectual content; Misra R contributed to acquisition of data and analysis; all authors issued final approval of the version to be submitted.
Conflict-of-interest statement: There are no conflicts of interest declared.
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: Naila Arebi, FRCP (Hon), MSc, PhD, Doctor, Department of Gastroenterology, St. Marks Academic Institute, Watford Rd, Harrow, London HA1 3UJ, United Kingdom. naila.arebi@imperial.ac.uk
Telephone: +44-208-8695328 Fax: +44-208-2354277
Received: August 28, 2017
Peer-review started: August 28, 2017
First decision: October 10, 2017
Revised: November 15, 2017
Accepted: November 21, 2017
Article in press: November 21, 2017
Published online: January 21, 2018
Abstract
AIM

To summarise the current literature and define patterns of disease in migrant and racial groups.

METHODS

A structured key word search in Ovid Medline and EMBASE was undertaken in accordance with PRISMA guidelines. Studies on incidence, prevalence and disease phenotype of migrants and races compared with indigenous groups were eligible for inclusion.

RESULTS

Thirty-three studies met the inclusion criteria. Individual studies showed significant differences in incidence, prevalence and disease phenotype between migrants or race and indigenous groups. Pooled analysis could only be undertaken for incidence studies on South Asians where there was significant heterogeneity between the studies [95% for ulcerative colitis (UC), 83% for Crohn’s disease (CD)]. The difference between incidence rates was not significant with a rate ratio South Asian: Caucasian of 0.78 (95%CI: 0.22-2.78) for CD and 1.39 (95%CI: 0.84-2.32) for UC. South Asians showed consistently higher incidence and more extensive UC than the indigenous population in five countries. A similar pattern was observed for Hispanics in the United States. Bangladeshis and African Americans showed an increased risk of CD with perianal disease.

CONCLUSION

This review suggests that migration and race influence the risk of developing inflammatory bowel disease. This may be due to different inherent responses upon exposure to an environmental trigger in the adopted country. Further prospective studies on homogenous migrant populations are needed to validate these observations, with a parallel arm for in-depth investigation of putative drivers.

Keywords: Epidemiology, Ethnicity, Migration

Core tip: We reviewed the literature on the epidemiology of inflammatory bowel disease (IBD) in migrants and racial groups. Thirty-three studies met the inclusion criteria. Individual studies showed significant differences in incidence, prevalence and disease phenotype between migrants or race and indigenous groups. Only the incidence studies were sufficient in number and comparable for pooled analysis and meta-analysis. There was a trend for higher incidence for ulcerative colitis and lower incidence for Crohn’s disease in South Asian migrants. This review suggests that migration and race influence the risk of developing IBD. This may be due to different inherent responses upon exposure to an environmental trigger in the adopted country.