in the period 1963-82 among the patients with aspecific inflammatory bowel disease , the incidence of ulcerative colitis was 3.1 per 100 000 per year , while the frequency of crohn 's disease has doubled during the observation period and now its incidence is 0.58 per 100 000 per year .
C0021390
inflammatory bowel
C0010346
crohn 's disease