Review article: epidemiology of IBS and other bowel disorders of gut–brain interaction (DGBI)

The disorders of gut–brain interactions (DGBI) are a spectrum of gastrointestinal (GI) disorders that involve the entire GI tract and are usually categorised into four major anatomic GI regions, oesophageal, gastroduodenal, bowel and anorectal. Irritable bowel syndrome (IBS), a bowel DGBI, is one of the most researched DGBI and has been the subject of copious epidemiological studies. Prevalence rates are based on diagnostic criteria. In the case of IBS, there are three central obstacles to attaining a clear picture of prevalence: the absence of biomarkers, the multitude of diagnostic criteria used over the years, and the heterogeneous nature of the methodology used in epidemiologic surveys. When the results of multiple studies, conducted over a long period of time, using different diagnostic criteria and different research methodology, and involving different study populations are pooled to determine a single summary prevalence rate it is difficult to interpret the results and to determine their reliability and significance. This pitfall is insufficiently recognised and unfortunate because prevalence rates are important for understanding the burden of disease, for allocating healthcare and research resources, and for incentivising and prioritising new treatments. The aims of the present paper are to highlight our knowledge and understanding of IBS epidemiology within the context of other DGBI, and to present strategies to improve epidemiological research, especially in advance of the new Rome V criteria, to be published in 2026.