Inflammatory Bowel Disease.

Abstract

Introduction: In the 21st century IBD has evolved into a global disease. We evaluated population-based studies reporting the incidence of IBD across the world since 1990 based on different geographical regions and performed temporal trend analyses of incidence rates. Methods: We performed a systematic review, through 31 December 2016, to identify population-based studies reporting incidence of Crohn's disease (CD) or ulcerative colitis (UC) from 1990 or after. Choropleth maps were created for the incidence of CD and UC for the time period 1990 to 2016. We performed temporal trend analyses using Poisson regression reported as annual percent change (APC) with 95% confidence intervals (CI). Results: Amongst 11,170 reports screened, 226 full-text reviews were identified and 113 incidence studies included. The incidence of CD and UC (Figure 1 and 2)are presented in worldwide maps. Overall, 70.0% of CD and 83.3% of UC studies demonstrated stable or decreasing incidence of IBD in North America, Europe, and Oceania. Since 1990, incidence has been rising in newly industrialized countries outside the Western world. For example, Brazil (CD: APC=+11.1, 95% CI: 4.8, 17.8; UC: APC=+14.9, 95% CI: 10.4, 19.6), Taiwan (CD: APC=+4.0, 95% CI: 1.0, 7.1; UC: APC=+4.8, 95% CI: 1.8, 8.0).Figure: Map of worldwide incidence in quintiles for Crohn's disease.Figure: Map of worldwide incidence in quintiles for ulcerative colitis.Conclusion: This systematic review provides a comprehensive global overview of the incidence of IBD over the past generation. We have observed a paradigm shift in the epidemiology of IBD. Since 1990, the incidence of IBD has stabilized in the Western world. In contrast, newly industrialized countries are showing rising incidence analogous to trends observed in the Western world during the latter part of the 20th century.