ULCERATIVE-COLITIS AND INDETERMINATE COLITIS IN THE CITY OF MALMO, SWEDEN - A 25-YEAR INCIDENCE STUDY

Background: This study was designed to assess time trends in the incid ence of ulcerative colitis and indeterminate colitis in an urban popul ation. Methods: Medical records of in- and out-patients with inflammat ory bowel disease were reviewed by a panel to establish the diagnosis. All histopathologic specimens and almost all radiographs were re-exam ined. Results: During the time period 1958 to 1982 there were 354 new cases of definite ulcerative colitis, 117 of probable ulcerative colit is, and 100 of indeterminate colitis. This corresponds to an average a nnual incidence per 100,000 of 5.5, 1.8, and 1.6, respectively. The in cidence was higher in men than in women. Peak incidence was between 20 and 29 years, but indeterminate colitis was most common in 10- to 19- year-old males. The incidence was stable from 1958 to 1972 but then in creased in almost all age groups in both sexes. The increase in annual incidence of definite ulcerative colitis from 4.2 to 9.4/10(5) corres ponds to an average annual increase of about 5% (p < 0.001). The incre ase in the incidence of definite ulcerative colitis was due to an incr eased proportion of patients with proctitis. Conclusions: This study h as shown an increased incidence of ulcerative colitis and indeterminat e colitis, and we have found no reason to believe that this is a spuri ous finding.