Epidemiology of Crohn's Disease in Regio Leiden, the Netherlands

An epidemiologic study of inflammatory bowel disease lvas conducted in Regio Leiden, the Netherlands, between 1979 and 1983. Archives of endoscopy, radiology, pathology, and specialist letters were reviewed for suspected patients with inflummatory bowel disease, together with a survey of oJJ general practitioners to verify completeness of datu. One thousand forty patients were identified trnd each diagnosis was revierved. Two hundred ten patients had Crohn’s disease and 257 hod ulcerative colitis. Of the other 573 patients, the largest proportion (210/o) had incomplete dota for disease classifyration. Others had irritable bowel syndrome, diverticulitis, or ischemic or irradiation colitis; some were nonresident patients with inflammatory bowel disease treated within the region and others were out of the period for inclusion in this investigation. The incidence of Crohn’s disease was 3.9 per 10’ per year and the period prevalence was 48 per 10,‘. The sex-specific incidence was similnr, although the disease was sjgnificantly more common in women aged 20-29 yr. The prevalence in the city municipulities of Leiden and AJphen on the Rijn (63 per 10.‘) was similar but significnntly greater than in suburban (39 per IO”) or agrarian areas [i20 per 10”). This may be partially due to urban density but not to