INCIDENCE OF CROHNS-DISEASE IN 4 COUNTIES IN SOUTHEASTERN NORWAY, 1990-93 - A PROSPECTIVE POPULATION-BASED STUDY

Background: Standardized criteria for Crohn's disease (CD) have only r ecently been developed, and prospective community-based incidence stud ies have been performed only during the past 3 decades. Geographic var iations in incidence may therefore be due to differences in study desi gn. Methods: From 1 January 1990 to 31 December 1993 all new cases of CD in four counties in southeastern Norway were prospectively register ed. Results: A total of 225 new cases yielded an annual incidence of 5 .8/10(5), with the highest incidence in mixed rural-urban areas. A pea k of 11.2/10(5) in the annual incidence was found for the age group 15 to 24 years, with no significant differences in the overall annual in cidence by gender. An average duration of 6 months of disease before d iagnosis was unchanged during the 4 years. About half of the patients had isolated colonic disease, and one-quarter had isolated small-bowel disease. Conclusions: This study confirms the high incidence figures for Scandinavia, with a particularly high incidence in mixed rural-urb an areas. Ileocolonoscopy improves the accuracy of the diagnosis and o f the determination of disease extent, which may have therapeutic impl ications for the treatment and follow-up of patients.