New research identifies four epidemiological stages of Inflammatory bowel disease (IBD)

Inflammatory bowel disease (IBD), which includes Crohn’s disease and ulcerative colitis, is a chronic immune-mediated disorder of the gastrointestinal tract. Throughout the 20th century, it was largely regarded as a condition of the Western world with steadily increasing numbers of new cases diagnosed in North America, Europe, and Oceania. By the early 2000s, however, the incidence of IBD began to plateau in these regions, while newly industrialised nations in Asia and Latin America experienced a sharp rise in incidence.

The Global IBD Visualization of Epidemiology Studies in the 21st Century (GIVES-21) consortium of researchers included Dr Phoebe Hodges, clinical research fellow, and Professor Paul Kelly, Professor of Tropical Gastroenterology - both of the Blizard Institute in the Faculty of Medicine and Dentistry. The consortium's study published the results of their analysis of over a century's data from more than 500 epidemiology studies across 80 regions. Their results defined the evolution of inflammatory bowel disease through four distinct stages:

1. Emergence: Currently seen in low income countries, with both incidence and prevalence remaining low.
2. Acceleration in Incidence: Rapid rise in new diagnoses as regions industrialize and lifestyles shift, though total cases remain limited.
3. Compounding Prevalence: With incidence stabilizing, prevalence soars—driven by low mortality and accumulating cases in younger populations.
4. Prevalence Equilibrium: Projected in several high income regions by 2045, where new diagnoses balance disease related deaths, plateauing overall prevalence.

Professor Kelly said: "Queen Mary has been participating in a global study of the epidemiology of inflammatory bowel disease (IBD) across the globe. While IBD is now a common disorder in industrialised countries, predicted to reach 1% prevalence in Canada and Scotland by 2030, it has been uncommon in the global South. This is changing, however, and Hracs et al have set out a novel framework for understanding these global trends. The authors have identified four key stages in IBD epidemiology, from emergence and acceleration to compounding prevalence, over the period 1950-2024. Equilibrium, with no further increase in prevalence, is predicted to occur first in Canada by 2042. The modelling now possible through this international collaboration will help plan responses to this increasing burden on health services, and may help point to causation, a very elusive and contentious issue.”

Hracs, L. & Windsor, J.W. et al. Ng, S., & Kaplan G.G. Global Evolution of Inflammatory Bowel Disease across Epidemiologic Stages. Nature (2025)