The epidemiology of functional gastrointestinal disorders

Functional gastrointestinal disorders are most commonly divided into gastro-oesophageal reflux disease (GORD), dyspepsia and the irritable bowel syndrome (IBS). GORD is defined as having predominant reflux symptoms, and is nowadays not considered to be a subgroup of dyspepsia. Dyspepsia is divided into subgroups (ulcer-like, dysmotility-like, unspecified and sometimes, when reflux symptoms are combined with abdominal complaints, reflux-like dyspepsia). The clinical relevance of this is however doubtful. If dyspeptic symptoms occur with concomitant bowel habit disturbances, the subject is said to have IBS. In the clinical situation, the patients often present with symptom overlap, and with change in main symptom profile from time to time. Different definition makes prevalence reports less comparable. An approximate average in the literature of the three-month period prevalence of GORD is that it is reported by 10% of the population, of overall reflux symptoms by 25%, of dyspepsia (without predominant reflux symptoms) by 25%, of dyspepsia without concomitant reflux symptoms by 15% and of IBS by 15% of the population.