The epidemiology of inflammatory bowel disease: balance between East and West? A narrative review

Abstract: Ulcerative colitis (UC) and Crohn’s disease (CD) are two different disorders that constitute inflammatory bowel disease (IBD). The prevalence of IBD is increasing worldwide, affecting millions of individuals. The objective of this review is to present the evolving changes in the epidemiology when looking at disease occurrence in the East compared to the West based on the most recent data. The highest incidences and prevalences are found in Northern Europe and Northern America. The incidence and prevalence in Asia are rapidly increasing, however still at a low level compared to the West. The disease courses do not differ initially. The rate of surgical treatment has declined over time. Mortality figures might be slightly more favourable in the East. Both CD and UC patients are at an increased risk for developing cancer of the gastrointestinal tract compared to the general population. The prevalence of IBD is rapidly increasing due to chronicity with a lack of cure, the young age of onset, and low mortality and it may rise exponentially due to increasing incidence and population ageing. As the number of reports on the epidemiology in the East is increasing we can foresee an evolution of the IBD epidemiology influenced by the findings in Asia adding information on the epidemiology of IBD and possibly also on the environmental factors influencing the occurrence and course of IBD.