Viewpoint: Inflammatory Bowel Diseases Among Immigrants From Low- to High-Incidence Countries: Opportunities and...

The inflammatory bowel diseases [IBDs], inclusive of Crohn's disease [CD] and ulcerative colitis [UC], are chronic, progressive immune-mediated diseases associated with high morbidity and substantial economic impact. The pathogenesis implicates a complex interaction between environmental determinants and genetic susceptibility. Of concern, the incidence and prevalence of IBD are increasing globally, with the highest relative increase observed in developing and recently developed countries. One high-risk yet underappreciated population is immigrants from countries of low to high IBD incidence, as evidenced by epidemiologic studies demonstrating higher risk of IBD among second- versus first-generation and younger versus older immigrants from low- to high-incidence countries [LTHICs]. The reasons underlying these emerging patterns among immigrants are incompletely understood and provide enormous opportunities to better define the pathophysiology of IBD and move toward disease prevention or at least earlier diagnosis. The rapidity of this epidemiologic shift in the demographic profile of IBD, which was traditionally a disease of Caucasians in industrialized countries, strongly implicates non-genetic factors and gene-environment interactions in the pathophysiology of IBD among immigrants from LTHICs. The primary objectives of this Viewpoint are to [1] provide a focused overview of IBD epidemiology among immigrants from countries at differential IBD risk; [2] emphasize the potential to advance our understanding of IBD pathogenesis via targeted research efforts to delineate risk and protective determinants in this cohort; and [3] highlight disparities and barriers in IBD care, as well as the economic implications of the rising, yet underappreciated, disease burden among immigrants from LTHICs.