Increasing incidence of Crohn's disease.

Reports in the literature have shown an increased incidence of Crohn's disease. The incidence in Spokane, Washington, was calculated on the basis of number of first hospitalizations for that diagnosis at all private hospitals within the city. The incidence in 1971 was 5.9 per 100,000 population and increased to 8.8 per 100,000 population in 1981, which is the highest incidence reported in the literature. The number of admissions and operations for Crohn's disease increased threefold in that same time interval. Possible pitfalls of such incidence studies have been discussed. We believe our results indicate a true and continuing increase in the incidence of Crohn's disease.