Comparative incidence of Type I diabetes in children aged under 15 years from South Asian and White or Other ethnic backgrounds in Leicestershire, UK, 1989 to 1998

Aims/hypothesis. Estimates of incidence of Type I (insulin-dependent) diabe tes mellitus in childhood populations vary around the world. This study aim ed to estimate and compare the incidence of Type I diabetes in Leicestershi re of children of South Asian and White or Other ethnic backgrounds. Methods. All new cases of childhood-onset Type I diabetes diagnosed before 15 years of age in Leicestershire during the period 1989-98 were studied. P opulation data for Leicestershire from the 1991 census was used. Ethnicity was assigned to all children in the study according to their surnames. Inci dence rates (95%-Confidence limits) for the South Asian and white or other ethnic group were estimated and compared. Results. Over the 10-year period, 46 South Asian children and 263 children who were white or from another ethnic group fulfilled the criteria for incl usion in the study. Crude incidence rates per 100 000 person-years were 19. 2 (12.0, 29.1) girls and 20.3 (13.0, 30.3) boys for South Asians and 17.7 ( 14.8, 21.1) girls and 17.7 (14.8, 20.9) boys for whites/others. Age and sex -specific rates were higher for South Asians over 5 years of age but differ ences were not statistically significant. Conclusion/interpretation. Type I diabetes incidence rates for South Asian children in Leicestershire were very similar to those for children who were in the white/other ethnic group, in contrast to very low rates reported fr om Asia. The convergence of rates for South Asians with other ethnic groups in Leicestershire suggests that environmental factors are more important t han genetic predisposition in causing Type I diabetes in people of South As ian ethnic background.