Prevalence of irritable bowel syndrome in the French population according to the Rome I criteria.

Background: Irritable bowel syndrome (IBS) is a common functional gastro-intestinal disease. In the absence of specific markers, definition and hence diagnosis depend on clinical presentation. Of the various attempts to set criteria for IBS, the most recent are Rome I and Rome II classifications.

Aims: To estimate in a general population the prevalence of IBS using the modified Rome I criteria, and to investigate socio-demographic criteria, symptoms and management.

Methods: A total of 11,131 people aged 18 years and over, representative of the French population, were surveyed. A diagnostic questionnaire based on the modified Rome I criteria was used to identify IBS sufferers, who were then questioned further about the symptoms and medical management of their IBS.

Results: Of the 5,299 men and 5,832 women interviewed, 445 had IBS according to the Rome I criteria, a prevalence of 4% (95% CI: 3.6%-4.4%). IBS was more frequent in women (5.3%) than in men (2.5%), with a sex ratio (F/M) of 2.3. In 9.1% of sufferers, onset had occurred less than 12 months ago, a yearly incidence of 3.6 per 1,000 of the population. In 32.3% of IBS sufferers diarrhoea was predominant, and in 34.6% constipation was predominant. Of IBS sufferers 83.7% had consulted a physician for their condition, and 87.6% had taken medication for their IBS symptoms over the previous 12 months.

Conclusion: The prevalence of IBS observed in this study in France was close to the lower limit in published data (3 to 20%). Our results suggest that the Rome I criteria are not sensitive enough to detect all IBS patients in a population not actively seeking health care intervention for the condition. In this regard, the refined classification (Rome II) which was established after our study was carried-out should be evaluated.