A high incidence of type 1 diabetes and an alarming increase in the incidence of type 2 diabetes among young adults in Finland between 1992 and 1996

Abstract

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.

Childhood BMI trajectories and the risk of developing young adult-onset diabetes

“…The American Diabetes Association criteria [16] were used for the classification of diabetes. The data sources and the method of classification have been described in detail previously [17]. In total, 1,388 cases of type 1 diabetes and 1,121 cases of type 2 diabetes were identified and chosen as the diabetes cases for this study.…”

“…1 BMI growth curve illustrating the BMI maximum and the BMI minimum. a the maximum BMI value in the infancy component; b the age at which the maximum BMI value in the infancy component is reached; c the minimum BMI value in the childhood component (the BMI rebound); d the age at which the minimum BMI value in the childhood component is reached diabetes in the Finns aged 15-39 years who were examined [17]. The study population was almost exclusively of Europid origin.…”

“…Therefore, observed rather than estimated values were extracted from this component. Cases obtained from the incidence of young adult-onset diabetes in Finland study [17] Two Fig. 2 Method of data collection.…”

The effect of birth order and parental age on the risk of type 1 and 2 diabetes among young adults

“…The inclusion criterion was a consistent diagnosis from at least two data sources, and the date of diagnosis was set as the date of the first entry in any one of these registers. The methods for the classification of diabetes have been described in detail previously [27]. In total, 4,478 individuals who fulfilled the inclusion criterion were identified from these four data sources, 485 of whom could not be reliably classified as having type 1 or type 2 diabetes and were excluded from the study.…”

“…This number comprises all type 1 and type 2 diabetes cases identifiable from the registers for the period between 1992 and 1996 in patients aged 15-39 years in Finland. The degree of ascertainment estimated using the capturerecapture method [29] for type 1, type 2 and undefined type of diabetes was 88% overall [27].…”