Observational Study
Copyright ©The Author(s) 2023. Published by Baishideng Publishing Group Inc. All rights reserved.
World J Methodol. Dec 20, 2023; 13(5): 475-483
Published online Dec 20, 2023. doi: 10.5662/wjm.v13.i5.475
Inflammatory bowel disease among first generation immigrants in Israel: A nationwide epi-Israeli Inflammatory Bowel Disease Research Nucleus study
Mira Stulman, Gili Focht, Yiska Loewenberg Weisband, Shira Greenfeld, Amir Ben Tov, Natan Ledderman, Eran Matz, Ora Paltiel, Shmuel Odes, Iris Dotan, Eric Ian Benchimol, Dan Turner
Mira Stulman, Gili Focht, Dan Turner, The Juliet Keiden Institute of Pediatric Gastroenterology and Nutrition, Shaare Zedek Medical Center, Faculty of Medicine, The Hebrew University of Jerusalem, Jerusalem 9103102, Israel
Mira Stulman, Ora Paltiel, Braun School of Public Health and Community Medicine, Hadassah Medical Organization, Faculty of Medicine, Hebrew University of Jerusalem, Jerusalem 9574869, Israel
Yiska Loewenberg Weisband, Clalit Research Institute, Tel Aviv 6209804, Israel
Shira Greenfeld, Amir Ben Tov, Maccabi Health Services and the Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv 6801296, Israel
Natan Ledderman, Meuhedet Health Services, Tel Aviv 6203854, Israel
Eran Matz, Leumit Health Services, Tel Aviv 6473704, Israel
Shmuel Odes, Faculty of Health Sciences, Ben-Gurion University of the Negev, Beer-Sheva 84105, Israel
Iris Dotan, Department of Gastroenterology, Rabin Medical Center, Petah Tikva 49100, Israel
Eric Ian Benchimol, Department of Paediatrics and Institute of Health Policy, Management and Evaluation, The Hospital for Sick Children, University of Toronto, Toronto M5G 1X8, ON, Canada
Eric Ian Benchimol, SickKids Inflammatory Bowel Disease Centre, Division of Gastroenterology, Hepatology and Nutrition, Child Health Evaluative Sciences, The Hospital for Sick Children and the SickKids Research Institute, Toronto M5G 1X8, Canada
Eric Ian Benchimol, ICES, Toronto M4N 3M5, Canada
Author contributions: Stulman M designed and conceptualized the study, collected, analyzed, and interpreted the data, and drafted the manuscript; Focht G, Loewenberg Weisband Y, Greenfeld S, Ben Tov A, Ledderman N, and Matz E contributed to data acquisition; Paltiel O, Odes S, Dotan I, and Benchimol EI contributed in data analysis and interpretation; Turner D designed and conceptualized the study, contributed to data analysis and interpretation, and drafted the manuscript.
Supported by the Leona M. and Harry B. Helmsley Charitable Trust, No. G-2018PG-CD009.
Institutional review board statement: The Institutional Review Board of Shaare Zedek Medical Center approved the study (Approval No. SZMC-0134-17).
Informed consent statement: The Shaare Zedek Medical Center IRB has waived the requirement to obtain informed consent.
Conflict-of-interest statement: All the authors declare that they have no conflicts of interest to disclose.
Data sharing statement: No additional data are available.
STROBE statement: The authors have read the STROBE Statement—checklist of items, and the manuscript was prepared and revised according to the STROBE Statement—checklist of items.
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: https://creativecommons.org/Licenses/by-nc/4.0/
Corresponding author: Dan Turner, MD, PhD, The Juliet Keiden Institute of Pediatric Gastroenterology and Nutrition, Shaare Zedek Medical Center, Faculty of Medicine, The Hebrew University of Jerusalem, Shmuel (Hans) Beyth St 12, Jerusalem 9103102, Israel. turnerd@szmc.org.il
Received: September 13, 2023
Peer-review started: September 13, 2023
First decision: October 7, 2023
Revised: October 17, 2023
Accepted: November 3, 2023
Article in press: November 3, 2023
Published online: December 20, 2023
Research background

Israel has a high rate of Jewish immigration and a high prevalence of inflammatory bowel disease (IBD). The study of IBD among immigrants is of paramount importance for several compelling reasons. Immigration itself facilitates population growth and changes in demographics, thereby influencing prevalence trends. Moreover, immigration introduces individuals to new environments, dietary habits, hygiene practices, and lifestyle behaviors, which can significantly alter their risk of developing IBD as they assimilate into their host countries.

Research motivation

Investigating IBD among immigrants provides a unique opportunity to dissect the complex interplay between genetics, environment, and migration in disease development, especially if focusing on a specific ethnic group of immigrants with similar predisposition to IBD. In this study, we compared IBD rates between first-generation immigrants originating from countries of varying IBD risk vs Israel-born residents, focusing specifically on the Jewish population in an effort to narrow the genetic variation of IBD that is usually present in immigration cohorts, in an increasingly interconnected world.

Research objectives

We aimed to compare the rate of IBD in first-generation immigrants vs Israel-born residents using a nationwide cohort of patients with IBD. We also aimed to determine whether the duration of residence in Israel affects the rate of IBD in these immigrants. Finally, we aimed to examine whether the rate of IBD in immigrants is related to the IBD risk in their country of origin.

Research methods

Patients with a diagnosis of IBD as of June 2020 were included from the validated Israeli IBD Research Nucleus cohort that includes 98% of the Israeli population. We stratified the immigration cohort by IBD risk according to country of origin, time period of immigration, and age group as of June 2020.

Research results

Of the 33544 Jewish patients that were ascertained, 18524 (55%) had Crohn’s disease and 15020 (45%) had ulcerative colitis (UC); 28394 (85%) were Israel-born and 5150 (15%) were immigrants. UC was more prevalent in immigrants (2717; 53%) than non-immigrants (12303, 43%, P < 0.001), especially in the < 1990 immigration period. The prevalence was higher in patients immigrating from countries with high risk for IBD (561.4/100000) than those originating from intermediate-/low-risk countries (514.3/100000; P < 0.001); non-immigrant prevalence was 528.9/100000. After adjusting for age, longer duration in Israel was associated with a higher point prevalence rate in June 2020 (high-risk origin: Immigration < 1990: 645.9/100000, ≥ 1990: 613.2/100000, P = 0.043; intermediate/low-risk origin: < 1990: 540.5/100000, ≥ 1990: 192.0/100000, P < 0.001).

Research conclusions

Our focus on the Jewish population was aimed at narrowing the genetic variation of IBD that is usually present in immigration cohorts. We found that the prevalence rate was lower among patients from intermediate-and low-risk regions compared to patients from high-risk regions but in both, the prevalence increased in association with duration in Israel after immigration. This finding, especially among immigrants from intermediate- and low-risk countries, lends support toward the role of environmental factors in IBD pathogenesis in Israel.

Research perspectives

Future studies should explore associations between immigration with time to IBD onset, and should examine specific environmental factors among immigrants to further our understanding of the elusive IBD etiology.