Incidence of Crohn's disease in Cardiff between 1934-1977.

The incidence of Crohn's disease in Cardiff between 1934 and 1977 has been examined using hospital diagnostic indices and supplemented in recent years by personal records from clinicians. A total of 232 cases of Crohn's disease were confirmed after all the notes had been reviewed. There has been a large increase from 0.18/cases/10(5) of the population per year in the 1930s to 4.8 cases/10(5)/year in the 1970s. The major change in incidence is thought to be real rather than apparent and involves all forms of the disease in each age group. The recognition of Crohn's disease of the colon in recent years appears to have played a minor part in the rise in incidence.