Phenotypic Differences in Inflammatory Bowel Diseases Across Race, Ethnicity, and Geography: A Systematic Review of 237 Population-Based Studies.

BACKGROUND & AIMS: Geography and ethnicity may influence disease phenotypic expression in the global emergence of inflammatory bowel disease (IBD). We performed this systematic review and meta-analysis to update the transethnic and migration impact on IBD epidemiology and phenotype.

METHODS

We included all population-based cohort data examining phenotype and/or outcomes of patients with Crohn's disease (CD) or ulcerative colitis (UC) published through December 2024. Pooled estimates of demographics, phenotypes, and outcomes across ethnic groups were compared across included cohorts. Within the cohort of those of Asian origin, we separately compared phenotype across different regions within Asia, and by immigrant status.

RESULTS

Our final analysis included a cohort of 237 population-based studies reporting outcomes of 1,251,682 patients with IBD. Among patients with CD, we observed higher rates of perianal disease (24%) in Asian individuals when compared with White individuals (14%) and those of Hispanic ethnicity (13%) (P < .01). On the contrary, no similar differences were observed in patients with UC. Among those of Asian descent, a family history of IBD was significantly more common among Middle Eastern individuals (12%) than South Asian individuals (3%) (P < .01) and was more notable among immigrants than native residents (12% vs 4%; P < .01). There were more males among Whites (51%) and Asians (60%), but females predominated in Blacks (55%, P < .01).

CONCLUSIONS

This global, transethnic meta-analysis revealed persistent differences in IBD phenotype and outcomes across ethnic groups. Future studies integrating multi-omic measurements in ethnically diverse populations are essential to elucidate the biologic basis of these variations.