The effects of migration on ulcerative colitis: A three-year prospective study among Europeans and first- and second-generation South Asians in Leicester (1991-1994)

OBJECTIVE: Our aim was to measure prospectively the incidence of ulcerative colitis in Leicester City and to compare this with a previous retrospective study in the same area. We also sought to compare the incidence and disease extent in the European community with that of the South Asian community and to compare the disease extent between first-and second-generation South Asian migrants. METHODS: A 3-yr prospective study of ulcerative colitis in the city of Leicester took place from October 1, 1991 to September 30, 1994 and included all cases resident in Leicester City and diagnosed as having ulcerative colitis, regardless of the extent and severity of the disease. RESULTS: Extensive colitis was commoner in second-generation migrants than in the first generation (x(2) = 4.3, p = 0.04) and was comparable to the European community. The annual average incidence of ulcerative colitis was 9.1/10(5) population/yr (95% confidence interval [CI] 7.1-11.3), which is similar to the previous retrospective study. However, the annual average incidence of ulcerative colitis in the European population was 7.0/10(5) population/yr (95% CI 5-9.5), whereas that of the South Asian population was 17.2/10(5) population/yr (95% CI 11.8- 24.3), confirming that the risk of ulcerative colitis in this particular community is exceptionally high. CONCLUSIONS: These early results suggest that the disease pattern follows that of the indigenous population after only one generation and requires monitoring over the next decade. The incidence of ulcerative colitis in the South Asian population is high and continuing to rise. (C) 1999 by Am. Coll. of Gastroenterology.