The incidence of ulcerative colitis in Northern Norway from 1983 to 1986. The Northern Norwegian Gastroenterology Society.

In a 3-year prospective epidemiologic multicentre study in Northern Norway the average annual incidence of ulcerative colitis was 12.8 per 100,000. Both inpatients and outpatients were included. There was a significant sex difference in annual incidence in the health region (15.1 per 100,000 in males versus 10.4 per 100,000 in females), which was most pronounced Nordland county (16.6 per 100,000 in males versus 10.4 per 100,000 in females). The highest incidence was seen in the age group 20-29 years, with an incidence of 30.3 in men and 20.3 in women per 100,000 per year. A family history of first-degree relatives with inflammatory bowel disease was obtained in 10.1%. The pathologic changes were equally distributed among the rectum and the distal and total colon. Ulcerative colitis located to the distal colon seemed more associated with extraintestinal manifestations.