INCIDENCE AND PREVALENCE OF ULCERATIVE-CO LITIS - A PROSPECTIVE-STUDYIN AN URBAN-POPULATION IN GERMANY (WESTERN RUHR AREA)

A prospective epidemiological study of the incidence and prevalence of ulcerative colitis was conducted from 1980 to the end of 1984. The po pulation at risk comprised 1.6 million inhabitants in the four industr ial cities Essen, Duisburg, Mulheim and Oberhausen of the western Ruhr -area. All 35 hospitals of the area with 79 departments of internal me dicine, surgery and pediatrics with in- and outpatients took part in t he study. 225 patients with substantial ulcerative colitis (excluded p roctitis) were newly diagnosed during the study period (129 men, 96 wo men); patients suffering only from ulcerative proctitis were not inclu ded. The mean incidence was 2.9 new cases per 100.000 inhabitants and year ranging from 2.3 to 3.7 without significant difference between th ese 5 years. Incidence figures were somewhat higher for men (3.5) than for women (2.4) and this difference was significant (p < 0.05). The a ge- and sex-adjusted incidence was found to have a broad range for bot h sexes between 20 and 65 years of age without a high incidence-peak i n young adults or a second peak later in life. Additionally all former ly diagnosed cases of ulcerative colitis were registered during this t ime period and the hospital archives were looked backward for prevalen t cases til 1975 retrospectively. From all these cases the prevalence of ulcerative colitis at December 31, 1984 was calculated for 27.3 pat ients per 100.000 inhabitants (n = 417) similarly with a significant p reponderance of men against women (31.1 vs. 22.1 per 100.000 inhabitan ts, p < 0.05). The distribution of the localisation of ulcerative coli tis was 30.2% distal colitis (rectum and sigmoid colon), 39.6% left-si ded colitis and 30.2% (sub-)total extension including 2.2% >>backwash ileitis<< in the terminal ileum. These figures range in the same level like data from USA and North-western Europe for substantial ulcerativ e colitis. Supposing that half of the patients with ulcerative colitis only suffer from proctitis (supported by the literature) which can be found only in a minor part by a hospital study we expect a total inci dence for ulcerative colitis of 4-6 new diagnoses per 100.000 inhabita nts and year and a prevalence of 40-60 patients per 100.000 inhabitant s.