EPIDEMIOLOGY IN INFLAMMATORY BOWEL-DISEASE - UNANSWERED QUESTIONS - EUROPEAN PERSPECTIVE

Several European epidemiological studies have shown similar patterns for Crohn's disease, demonstrating.an increase in incidence over the past 30 years. It has, however, not been revealed whether the apparent differences in incidence, with a much higher value in the north than in the south of Europe, are real. A European multicentre study, comprising 20 centres, is being carried out over the next three years, using well defined and equal diagnostic criteria. From published epidemiological studies, it appears that the disease entities for ulcerative colitis and Crohn's disease have remained practically unchanged during the past two decades, as regards clinical appearance at diagnosis. The different pattern in incidence of ulcerative colitis (almost steady) and Crohn's disease (steep increase) supports the concept of two different diseases. The steep increase in occurrence of Crohn's disease points to an external factor in the etiology of the disease.