Background: The incidence of Crohn's disease rose rapidly in industralized countries over the past 50 years, but it is unclear whether the incidence is still rising or has reached a plateau.
Aims: To update the long-term incidence study of Crohn's disease in Cardiff for 1996-2005, to investigate whether incidence is still rising and to study changes in disease characteristics over time.
Method: Crohn's cases identified by retrospective analysis of hospital records as in previous studies in Cardiff.
Results: Two hundred and twelve cases were identified. Corrected incidence for this decade was 66 x 10(6) per year (95% confidence interval: 58-76), showing a continuing rise compared to previous decades. The proportion with colonic disease at presentation continues to rise (43%) with a corresponding fall in those with terminal ileal disease. There remains a strong female preponderance (F:M 1.6:1) as in previous studies. The incidence in children under age 16 continues to rise, and the median age at diagnosis has fallen slightly.
Conclusion: Crohn's disease incidence continues to rise slowly in Cardiff with a continuing increase in those presenting with colonic disease, which is now the commonest disease pattern.