[Prospective study of the incidence and prevalence of ulcerative colitis in a large 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 population at risk comprised 1.6 million inhabitants in the four industrial cities Essen, Duisburg, Mülheim and Oberhausen of the western Ruhr-area. All 35 hospitals of the area with 79 departments of internal medicine, surgery and pediatrics with in- and outpatients took part in the study. 225 patients with substantial ulcerative colitis (excluded proctitis) were newly diagnosed during the study period (129 men, 96 women); patients suffering only from ulcerative proctitis were not included. 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 these 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 age- and sex-adjusted incidence was found to have a broad range for both sexes between 20 and 65 years of age without a high incidence-peak in young adults or a second peak later in life. Additionally all formerly diagnosed cases of ulcerative colitis were registered during this time period and the hospital archives were looked backward for prevalent cases til 1975 retrospectively. From all these cases the prevalence of ulcerative colitis at December 31, 1984 was calculated for 27.3 patients per 100,000 inhabitants (n = 417) similarly with a significant preponderance of men against women (31.1 vs. 22.1 per 100,000 inhabitants, p < 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)