Incidence of Type I diabetes mellitus in children and young adults in the province of Upper Austria, 1994-1996

Aims/hypothesis. The aim of our study was to determine the incidence rate of Type I (insulin-dependent) diabetes mellitus in the 15-30 years age group in a well-defined province in Austria and to compare this with the incidence rate of childhood-onset diabetes mellitus in the age group 0-15 over a 3-year period. Methods. Incident cases of Type I diabetes were reported by the local departments of medicine and paediatrics prospectively to the Austrian Diabetes incidence registry. Completeness of ascertainment was calculated by the capture-recapture method. Results. The incidence rates per 100 000 person-years for Type I diabetes in the Austrian province of Upper Austria were 8.99 (7.02-11.4, 95 % -CI) for the 0-15 years age group and 7.1 (5.5-9.0, 95 % -CI) for the 15-30 years age group. The estimated completeness of ascertainment was 93 % (89.0-97.1 %, 95 % CI) for children and 87 % (84.1-89.9 %, 95 % -CI) for young adults. Sex differences were evident in young adults, with a 1.6-fold increased risk in males older than 15 years and 2.2-fold increased risk in men over 20 years of age. Conclusion/interpretation. Our study shows that the incidence rate of Type I diabetes in Austria after the age of 15 years is similar to the incidence rate in childhood. An unexplained male predominance in patients older than 20 years could be observed as in several other countries.