[Epidemiology, pathogenesis, course and sequelae of Crohn's disease]

In Crohn's disease epidemiological data show a 5-fold increase in incidence between 1950 and 1970. The incidence in towns is higher than in rural areas. The significance of environmental factors such as sugar, fat and nicotine has not been established. L-forms of mycobacteria may be the cause of the disease. Intestinal immunoregulation is not impaired. The natural history is poorly influenced by drugs and "curative" resection. Male, but not female, fertility may be impaired. There is only a slightly increased risk of cancer.