Crohn's disease in Jewish people--an epidemiological study in south-east Wales.

The prevalence of Crohn's disease in the Jewish population of south-east Wales was established by a postal survey, review of case notes and a survey of Jewish congregations in the three synagogues of the area. The prevalence of Crohn's disease had been established in various earlier studies at 52/10(5). Seven Jewish patients were identified amongst a population of between 1,750 and 2,500. The prevalence ranged from 280 to 400/10(5) (95% confidence interval 120-862/10(5]. There was no significant difference in prevalence between orthodox and reformed Jews. Jewish people are at a relative risk of developing Crohn's disease of 5.4-7.7 (95% confidence interval 2.3-17.2, p less than 0.001), but the role of diet is yet to be established.