Rome V global epidemiology: 40.9% of adults have a disorder of gut-brain interaction

If you have spent years being told your gut symptoms are stress, or that your tests came back normal so nothing is wrong, a survey of nearly thirty thousand people just quietly made your case for you. Two in five adults on the planet meet the criteria for a diagnosable gut-brain disorder. The single most common bowel diagnosis is now the one that essentially means "your symptoms are real but they don't fit a tidy box." And two complaints that patients are routinely told are imaginary — a migraine that happens in your abdomen, and simply being unable to burp — now have official global prevalence numbers attached to them.

Key takeaways

• 40.9% of adults worldwide meet criteria for at least one disorder of gut-brain interaction under the new Rome V rules — almost identical to the 40.5% found under the older Rome IV criteria.
• Unclassified bowel disorder (9.6%) is now the most common bowel diagnosis, ahead of chronic constipation (8.9%) and IBS (8.5%). Not fitting a clean diagnostic category is the norm, not the exception.
• Abdominal migraine (5.1%) and inability to belch syndrome (1.4%) received their first global prevalence estimates. They are recognised conditions with numbers, not quirks.
• This is a self-report internet survey with no clinical confirmation, funded and co-authored by the foundation whose criteria it validates. It tells you how common these conditions are and nothing about what causes them.

Rome V finds 40.9% global prevalence of gut-brain disorders

Roughly 40.9% of adults meet the criteria for at least one disorder of gut-brain interaction, according to the Rome V global epidemiology and validation survey published in the BMJ journal Gut on 18 August 2026. A disorder of gut-brain interaction, or DGBI, is a chronic gut condition defined by its symptom pattern rather than by visible damage — the category that used to be called "functional" gastrointestinal disorders, and that includes irritable bowel syndrome, functional dyspepsia and chronic constipation.

The number that makes this interesting is the one it was checked against. The Rome IV global study, run with the previous generation of diagnostic criteria, found 40.5%. Two different criteria sets, applied to different samples, landed four-tenths of a percentage point apart. The team, led by Ami D Sperber at Ben-Gurion University of the Negev with Olafur S Palsson at UNC Chapel Hill as senior author, concluded that this "bolsters confidence in the validity of prevalence rates for DGBI and reaffirms their high global burden." In both surveys, prevalence was higher among females and decreased as age increased.

Why 40% prevalence matters if you have IBS or functional dyspepsia

If you are managing IBS, functional dyspepsia, chronic constipation or an undiagnosed gut complaint, the practical meaning of 40.9% is that you are in an enormous and well-documented group, not an anomalous one. That matters because DGBI have historically been treated as a diagnosis of exclusion — the label you get when the scope and the bloodwork come back clean — which too often gets communicated to patients as nothing is wrong.

The survey covered 25 distinct DGBI, and the specific figures are worth knowing because they tell you where your complaint sits. In the oesophagus, functional dysphagia (difficulty swallowing with no structural cause) was the most prevalent at 4.1%. In the stomach and duodenum, functional dyspepsia (persistent upper-abdominal pain, fullness or early satiety) led at 8.1%. Among anorectal disorders, proctalgia fugax (sudden, severe, self-limiting rectal pain) came in at 7.3% — a startlingly high figure for a condition most people have never heard named.

Unclassified bowel disorder outranks IBS at 9.6% prevalence

The most common bowel disorder in the world is not IBS. It is unclassified bowel disorder at 9.6%, ahead of chronic constipation at 8.9% and IBS at 8.5%. Unclassified bowel disorder is the category for people with genuine, criteria-meeting bowel symptoms that do not satisfy the definition of IBS, constipation, diarrhoea or bloating specifically.

Read that ranking again, because it reframes a common experience. The largest single group of people with a bowel disorder are the ones whose symptoms cross categories or sit between them. If you have been bounced between an IBS-D label and an IBS-C label, or told your presentation is "atypical," the epidemiology says atypical is the plurality position. The diagnostic boxes are a clinical convenience; a tenth of the adult population lives outside all of them while still being unwell.

Abdominal migraine and inability to belch get first global numbers

Two conditions newly recognised in Rome V received their first population-level prevalence estimates: abdominal migraine at 5.1% and inability to belch syndrome at 1.4%. Abdominal migraine involves recurrent episodes of intense abdominal pain with symptom-free intervals, following a migraine-like pattern in the gut rather than the head. Inability to belch syndrome describes exactly what it sounds like — the upper oesophageal sphincter does not relax to release trapped air, producing gurgling, chest and neck pressure, and bloating.

Both have long been the sort of complaint that gets a raised eyebrow in a consulting room. At 5.1%, abdominal migraine is more common than IBS-adjacent conditions that get far more clinical airtime. At 1.4%, inability to belch is rarer, but 1.4% of adults is still a very large number of people who have been told, incorrectly, that everyone can burp.

What a prevalence survey can and cannot tell you

This study can tell you how many people have these conditions. It cannot tell you why, and it cannot tell you what to do about it. There is no mechanism here, no microbiome finding, no treatment signal, and no causal claim of any kind — the design is cross-sectional, meaning it photographs a population at one moment rather than following anyone over time.

What it is genuinely useful for is a conversation with a clinician. If your symptoms have never fit IBS cleanly, "unclassified bowel disorder" is a real Rome V category and now the most prevalent one; it is reasonable to ask whether it describes you better than a forced IBS label. If you get episodic, severe abdominal pain with well periods in between, abdominal migraine is a named diagnosis worth raising. If you cannot burp and have been dismissed, the condition is in the criteria with a prevalence figure. None of that implies a treatment — this paper tested none, and no supplement, diet or protocol gains any support from it whatsoever. A name is not a therapy. It is, however, the thing that has to exist before anyone studies a therapy.

Internet-panel design and Rome Foundation funding limit the findings

The main limitations are the survey method and who paid for it. Every diagnosis here is self-reported through the Rome V diagnostic questionnaire — nobody was examined, scoped or seen by a doctor. Internet panels also exclude anyone not online, which systematically thins out older, poorer and rural populations, and this same research group has previously shown that internet surveys yield systematically different answers than face-to-face interviews. Fifteen countries, however large the sample, is not a random slice of the world.

The conflict of interest deserves stating plainly rather than burying: the Rome Foundation Research Institute funded this study, its staff and its founder Douglas A Drossman are among the co-authors, and the paper's stated purpose is validating the Rome V criteria that the same foundation authors and licenses. That is institutional and intellectual self-interest rather than an individual holding equity in a product. It does not invalidate a 28,771-person survey, but it means the finding "our new criteria agree with our old criteria" is being reported by the people who wrote both. I was unable to retrieve the rendered full text of the paper through any route, so the individual ICMJE conflict-of-interest declarations remain unverified — I am reporting the funder and author affiliations from Crossref metadata, not from a statement I read.

What comes next for Rome V criteria

The immediate consequence is that Rome V now has the population-level backing that clinicians and trialists need to use it. The Rome V revision process produced the criteria; this survey supplies the denominators. Expect the two new conditions to drive the most follow-up, since abdominal migraine at 5.1% and inability to belch at 1.4% now have baseline prevalences against which treatment studies can be sized. The obvious next questions — what drives unclassified bowel disorder, whether it is a genuine entity or a holding pen, and why prevalence falls with age — need longitudinal and clinical work that this survey design cannot do.

Common questions

Is a disorder of gut-brain interaction the same as a "functional" gut disorder? Broadly yes. DGBI is the current term for what used to be called functional gastrointestinal disorders, renamed to reflect that these conditions involve real, measurable disturbances in signalling between the gut and the brain rather than an absence of pathology.

Does 40.9% mean gut-brain disorders are getting more common? No. The near-identical 40.9% and 40.5% figures come from different criteria applied to different samples, so this is best read as two methods agreeing on roughly the same underlying burden, not as a trend over time.

What is unclassified bowel disorder? It is the Rome V category for people who meet the general definition of a bowel disorder of gut-brain interaction but do not fit the specific criteria for IBS, functional constipation, functional diarrhoea or functional bloating. At 9.6% it is the most prevalent bowel DGBI globally.

Should I ask my doctor about abdominal migraine or inability to belch? If your symptoms match the descriptions, they are legitimate named diagnoses in the current criteria and reasonable to raise. This study establishes only how common they are, not how to treat them, so any management discussion should be with a clinician who can assess you directly.

References

Ami D Sperber, Johann P Hreinsson, Magnus Simrén, et al. (2026). Rome V global epidemiology and validation survey: prevalence of disorders of gut–brain interaction and comparison with the Rome IV global epidemiology study. Gut. https://doi.org/10.1136/gutjnl-2026-339666