[Incidence and prevalence of inflammatory bowel disease in Gijon, Asturias, Spain]

To determine the incidence and prevalence of inflammatory bowel disease in our area and to compare our results with those of other series from Spain and other parts of the world.

Descriptive epidemiologic population study, retrospective (1954-1993) and prospective (1994-1997) in health district V of Gijón in Asturias (Spain) with 225,798 inhabitants. Diagnostic criteria used were those described by Lennard-Jones and Truelove for Crohn's disease and ulcerative colitis and those described by Ashley B. Price for indeterminate colitis. Annual incidence was expressed per 100,000 inhabitants. Prevalence was calculated excluding cured patients: proctocolectomized in ulcerative colitis (10 cases) and deaths (29 cases).

During the period studied, 595 patients were diagnosed with bowel disease (305 patients with ulcerative colitis, 272 with Crohn's disease and 18 with indeterminate colitis). Mean annual incidence (1954-1997) was 6.128 (95% CI: 2.90-9.36). In the 4-year prospective study the incidence was 15.49 (95% CI: 11.19-21.79), 9.36 for ulcerative colitis, 6.08 for Crohn's disease and 0.77 for indeterminate colitis (UC/CD: 1.58). Prevalence was 246.23 (95% CI: 225.6-226.70, 212.79 for ulcerative colitis, 116.47 for Crohn's disease and 7.97 for indeterminate colitis.

Incidence and prevalence obtained in our environment were higher than those described in other areas of Spain and were similar to those found in areas of Europe and other parts of the world with a higher incidence. Incidence and prevalence have increased since 1980, probably due to the widespread use of endoscopy as a diagnostic technique. Rates were higher in the prospective study than in the retrospective one.