A PROSPECTIVE ANALYSIS OF THE INCIDENCE AND PREVALENCE OF CROHNS-DISEASE IN AN URBAN-POPULATION IN GERMANY

Objective: To study the incidence and prevalence of Crohn's disease in the Ruhr area of Germany. Participants: The population at risk compri sed 1.6 million inhabitants in the four industrial cities of Essen, Ob erhausen, Mulheim and Duisburg. All 35 hospitals in the area, includin g 79 in- and outpatient departments of internal medicine, surgery and paediatrics participated in the study. Methods: A prospective epidemio logical study of the incidence and prevalence of Crohn's disease over 5 years from 1980 to the end of 1984. Results: Overall, 315 patients w ith Crohn's disease (181 women and 134 men) were newly diagnosed durin g the study period. The mean incidence was 4.0 new cases per 100 000 i nhabitants (range, 3.10-4.9) with no significant difference between th e 5 years. Incidence figures were somewhat higher for women than for m en (4.3 versus 3.6 per 100 000 inhabitants, respectively), but this di fference was significant only for those aged 20-29 years. The age- and sex-adjusted incidence was highest among those aged 20-29 years for b oth sexes with no second peak later in life. The prevalence of Crohn's disease on 31 December 1984 was calculated to be 36.0 per 100 000 inh abitants (n = 556). Seventy-four per cent of cases living in the area were under 35 years of age and 44% were under 25 years; 30 were childr en under the age of 15 (5.4%). Conclusion: These figures for Crohn's d isease eange in the upper level of those reported for western industri al areas.