Background: The incidence of ulcerative colitis (UC) shows a marked geographical variation. It is high in Anglo-Saxon and Scandinavian countries, while in Mediterranean countries the available data on its epidemiological features are few. Spain is not an exception.
Methods: The new cases of UC diagnosed during the period 1985-1989 in the Hospital de Sabadell (a reference center of an area with a markedly industrial population of 343924) were retrospectively evaluated. The definitive diagnosis of UC required a negative fecal microbiological study and findings in colonoscopy and biopsy consistent with UC.
Results: During the study period 68 new cases of UC were diagnosed, representing a mean yearly incidence of 3.95/10(5) population, and 5.26/10(5) considering only the adult population (age greater than 14 years). No significant differences were found (p greater than 0.05) in the sex and age distributions, although the male/female ratio was 1.06. In 84% of cases UC was limited to the rectum and/or distal colon, with a low frequency of pancolonic forms (5%). In 70% of patients UC was classified as a low severity disease.
Conclusions: Although the estimation of incidence only from hospital cases underestimates the true incidence, and also considering the limitation of comparing results of studies from several time periods, the incidence of UC in our area is the highest one reported to the present time in Spain and Southern Europe. Nevertheless, it is lower than that in most Northern European countries.