INFLAMMATORY BOWEL-DISEASE IN ICELAND, 1980-89 - A RETROSPECTIVE NATIONWIDE EPIDEMIOLOGIC-STUDY

Background: A previous nationwide epidemiologic study of inflammatory bowel disease (IBD) in Iceland in 1950-79 showed a low but steadily ri sing incidence. The incidence of IBD in Iceland in 1980-89 was investi gated and compared with reports from neighboring countries. Methods: C ases were retrieved by a review of all small-and large-intestinal tiss ue specimens with any type of inflammation submitted to the only two d epartments of pathology in Iceland. All small-intestinal X-ray records suggestive of Crohn's disease (CD) in the three major hospitals were also screened. All hospital and outpatient records of cases suggestive of IBD were then reviewed using accepted criteria for confirmation or exclusion. Results: The mean annual incidence of ulcerative colitis ( UC) was 11.7/100,000, and that of CD 3.1/100,000. The highest age-spec ific incidence of UC was in the group 30-39 years old and for CD in th e group 60-69 years old. The most frequent involvement at diagnosis of UC was proctitis only, in 54%, and in CD colon only, in 54.7% of the patients. Conclusions: This study shows a continuing increase in the i ncidence of both diseases. Compared with the period 1970-79, there has been an almost twofold increase in the mean annual incidence of UC an d more than a threefold increase of CD, a statistically significant in crease in both instances.