Published online Dec 20, 2023. doi: 10.5662/wjm.v13.i5.475
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
Processing time: 98 Days and 3.7 Hours
Israel has a high rate of Jewish immigration and a high prevalence of inflammatory bowel disease (IBD).
To compare IBD prevalence in first-generation immigrants vs Israel-born Jews.
Patients with a diagnosis of IBD as of June 2020 were included from the validated epi-IIRN (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.
A total of 33544 patients were ascertained, of whom 18524 (55%) had Crohn’s disease (CD) 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 in non-immigrants (12303, 43%, P < 0.001), especially in the < 1990 immigration period. 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). 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.
Lending support to the environmental effect on IBD etiology, we found that among immigrants to Israel, the prevalence of IBD increased with longer time since immigration, and was related to the risk of IBD in the country of origin. The UC rate was higher than that of CD only in those immigrating in earlier time periods.
Core Tip: In this nationwide study, we compared inflammatory bowel disease (IBD) rates between first-generation immigrants originating from countries of varying IBD risk vs Israel-born residents. 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.