The Consortium Global IBD Visualisation of Epidemiology Studies in the 21st Century (GIVES-21) published data on the global prevalence of inflammatory bowel disease (IBD) in Nature. Researchers from Karolinska Institute have contributed to the study. While the number of people with incident IBD is relatively constant in Sweden, the prevalence is increasing, and 1% of the Swedish population is now estimated to have IBD.

Inflammatory bowel disease (IBD) mainly consists of Crohn's disease and ulcerative colitis. IBD is a chronic immune-mediated disease of the gastrointestinal tract. Throughout the 20th century, IBD was primarily considered a condition that existed only in the Western world, but is now seen worldwide.

However, in the early 2000s, the number of people newly diagnosed with IBD ("incidence") began to level off in the Western world, although the prevalence continued to increase—the latter increase driven by the fact that individuals with IBD are largely diagnosed early in life and rarely die from the disease.

Swedish researchers from Karolinska Institutet have now participated in a very ambitious international initiative (GIVES-21) that has compiled data from more than 500 population-based studies on the prevalence of IBD from over 80 geographical regions and over 100 years of observations.

Using these data, four distinct phases in the development of IBD were identified, where stage 1 consists of single sporadic cases of IBD (e.g. Africa today); stage 2 is characterized by an increasing number of people with newly diagnosed IBD (i.e. the situation in many countries in Asia and Latin America), while stage 3 means that the number of new cases have slowed down, but the number of people living with IBD is still increasing. No country has yet reached stage 4, where the prevalence of IBD is expected to decrease.

Swedish conditions

"Even though the number of new cases has stabilised in Sweden, the prevalence of IBD continues to increase, and at the turn of the year (2024–25), it was 1% in Sweden. Today, one in a hundred Swedes lives with IBD," says one of the authors, Jonas F Ludvigsson, paediatrician at Örebro University Hospital, and professor at the Department of Medical Epidemiology and Biostatistics, Karolinska Institute.

"The study shows stabilising incidence rates of IBD in Europe, including Sweden, confirming our own previous findings. We expect constant new IBD cases in Sweden, but increasing prevalence will demand attention from the Swedish health care system," says Anders Forss, co-author and ST physician in gastroenterology and postdoctoral fellow at the Department of Medicine Solna, Division of Clinical Epidemiology, Karolinska Institutet.

"Pinpointing where each region is on the trajectory for IBD incidence and prevalence gives health-care systems a clear roadmap for anticipating and managing the rapidly growing burden of IBD today and in the decades to follow," says the study's third Swedish co-author; Ola Olén, chief physician at Sachsska Children's and Adolescents Hospital in Stockholm and professor at the Department of Medicine Solna, Department of Clinical Epidemiology, Karolinska Institutet.