Aims/hypothesis: The aim of this study was to examine the incidence and trends of type 1 and type 2 diabetes in the 15-39 year-old population between 1992 and 1996 in Finland.
Subjects and methods: Data on the nationwide incidence of diabetes were obtained from four data sources: standardised reports from diabetes nurses, the Finnish National Hospital Discharge Register, the Drug Reimbursement Register and the Drug Prescription Register. The inclusion criterion was consistency in the diagnosis of diabetes across at least two data sources. The sex- and age-specific incidence was calculated for 5-year age groups, both for type 1 and type 2 diabetes. The effects of age, sex and year of diagnosis were assessed by fitting the linear regression model to the incidence data.
Results: Between 1992 and 1996 the age-adjusted incidence of type 1 diabetes among 15-39 year olds was 15.9 per 100,000/year. The incidence was highest among the 15-19 year olds and decreased with age. Conversely, the incidence of type 2 diabetes was very low among 15-19 year olds and increased with age. The total age-adjusted incidence of type 2 diabetes among 15-39 year olds was 11.8 per 100,000/year. The average annual increase in the incidence of type 2 diabetes was 7.9% (95% CI 3.7-12.2%).
Conclusions/interpretation: The age at which the Finnish population is at risk of type 1 diabetes extends into young adulthood. The rapid increase in the incidence of type 2 diabetes in the young adult population is a current public health problem.