Aims/hypothesis: To study the epidemiology of childhood-onset (Type I) insulin-dependent diabetes mellitus in Europe, the EURODIAB collaborative group in 1988 established prospective, geographically-defined registers of all children diagnosed with Type I diabetes under 15 years of age. This report is based on 24,423 children, registered by 36 centres, with complete participation during the period 1989-1998 and representing most European countries with a population coverage of approximately 20 million children.
Methods: Multiple sources of ascertainment were used to validate the level of ascertainment. Trends in Type I diabetes incidence during the period were analysed using Poisson regression with the results from the 36 centres pooled into nine regions.
Results: The standardised average annual incidence rate of Type I diabetes varied more than tenfold between centres. Overall, the annual increase in incidence was 3.2% (95%-CI: 2.7%, 3.7%), being highest for children in the 0-4-year age-group 4.8% (3.8%, 5.9%) and lowest for children in the 10-14-year age group 2.1 % (1.4%, 2.8%). However, the absolute increases in Type I diabetes were roughly similar in the three age-groups of 0-4, 5-9 and 10-14 years. Central Eastern Europe showed the highest increase whereas Sardinia and Northern Europe (except Finland) showed no evidence of an increase. For all age-groups relatively fewer cases had disease onset during the summer months, especially the 10-14-year age-group.
Conclusion/interpretation: The extremely large range of incidence rates within Europe has been confirmed. The incidence rate is generally increasing but is more pronounced in some regions than in others. Seasonality at disease onset is apparent even in the youngest age-group.