Prevalence of irritable bowel syndrome according to different diagnostic criteria in a non-selected adult population

Background: Prevalence of irritable bowel syndrome shows great variation among epidemiological studies, which may be due to different diagnostic criteria. Aim: To assess prevalence of irritable bowel syndrome according to various diagnostic criteria and to study differences in symptom severity, psychopathology, and use of health care resources between subjects fulfilling different diagnostic criteria. Methods: A questionnaire was mailed to 5000 randomly selected adults. Presence of irritable bowel syndrome was assessed by four diagnostic criteria: Manning 2 (at least two Manning symptoms), Manning 3 (at least three Manning symptoms), Rome I and Rome II. Results: Response rate was 73%. Prevalence of irritable bowel syndrome by Manning 2, Manning 3, Rome I and Rome II criteria was 16.2%, 9.7%, 5.6%, and 5.1% respectively. Of those fulfilling Rome II criteria, 97% fulfilled Manning 2. Severe or very severe abdominal pain was reported by 27-30% of Manning-positive subjects, and 44% of Rome-positives. Prevalence of depression in Manning 2, and Rome II groups was 30.6 and 39.3%. Conclusions: Prevalence of irritable bowel syndrome by Rome II criteria is considerably lower than by Manning criteria. Subjects fulfilling Rome criteria form a subgroup of Manning-positive subjects with more severe abdominal symptoms, more psychopathology, and more frequent use of the health care system.