Incidence of Crohn's disease in Cardiff over 60 years: 1986-1990 an update

To report the incidence of Crohn's disease in the city of Cardiff between 1986 and 1990 and relate it to our previous incidence figures which extend over 60 years.

The incidence of Crohn's disease was examined using hospital diagnostic indices supplemented by records from clinicians and from the Department of Pathology, University Hospital of Wales, Cardiff, UK. In addition, a questionnaire was sent to all family practitioners in Cardiff asking them to identify patients in their practice.

Eighty-six new patients were confirmed after reviewing the notes of patients in whom a diagnosis of Crohn's disease was considered. The mean incidence for this quinquennium was 5.9 cases per 10(5) of the population per year (95% confidence interval 4.7-7.3), with the highest age-specific incidence between those aged 15 and 34 years. Colorectal disease was the most common site of disease at the time of diagnosis and this was particularly striking in those aged over 50 years.

The findings are related to our previous studies. The incidence of Crohn's disease has not continued to increase at the rate reported in early 1980s, but remains one of the highest reported in the literature. The colon has become the most commonly affected site, which may reflect an increase in diagnostic awareness.