[Crohn's disease in Iceland 1980-1989. A retrospective epidemiological study.]

To find the incidence of Crohn's disease in Iceland during the past decade for comparison with previous study and incidence figures from neighbouring countries.

A nationwide retrospective study of the incidence of Crohn's disease in Iceland for the 10-year period 1980-1989 was conducted. New cases were retrieved by review of all small and large intestinal tissue specimens with any type of inflammation submitted to the two departments of pathology in Iceland. All cases with the slightest possibility of Crohn's disease were followed clinically by examining their hospital, outpatient and x-ray records. In addition all small intestinal x-rays with the diagnosis of Crohn's disease were screened. The criteria of Lennard-Jones were used to confirm or exclude Crohn's disease.

Thus 75 patients were found, 36 men and 39 women, M/F ratio 0.9. The mean annual incidence was 3.1/100,000, which is a three fold increase compared to the period 1970-1979. The incidence of Crohn's disease in Iceland is still the lowest among the neighbouring countries. The highest age specific incidence was in the age group 60-69 years, 8.9/ 100,000, which is unusual. The most frequent localization of the intestinal inflammation at diagnosis was colon only (54.7%). The second most common localization was ileum only (25.3%), but in 18.7% of the patients the disease involved both ileum and colon. Inflammation limited to the colon was significantly more frequent in the older age groups. There was a family history of inflammatory bowel disease (IBD) in 8% of the cases.

The incidence of Crohn's disease in Iceland, while still low compared to that of the neighbouring countries, is rising. The reason for this increase is unknown.