The incidence of Type I diabetes has not increased but shifted to a younger age at diagnosis in the 0–34 years group in Sweden 1983 to 1998

Abstract

Aims/hypothesis. To analyse the incidence of Type I (insulin-dependent) diabetes mellitus in the 0-34 years age group in Sweden 1983-1998. Methods. Incidence and cumulative incidence per 100 000 and Poisson regression analysis of age-period effects was carried out using 11 751 cases from two nation-wide prospective registers. Results. Incidence (95%-CI) was 21.4 (20.8-21.9) in men and 17.1 (16.6-17.5) in women between 0 and 34 years of age. In boys aged 0-14 and girls aged 0-12 years the incidence increased over time, but it tended to decrease at older age groups, especially in men. Average cumulative incidence at 35 years was 748 in men and 598 in women. Cumulative incidence in men was rather stable during four 4-year periods (736, 732, 762, 756), while in women it varied more (592, 542, 617, 631). In males aged 0-34 years, the incidence did not vary between the 4-year periods (p=0.63), but time changes among the 3-year age groups differed (p<0.001). In females the incidence between the periods varied (p<0.001), being lower in 1987-1990 compared to 1983-1986, but time changes in the age groups did not differ (p=0.08). For both sexes median age at diagnosis was higher in 1983-1986 than in 1995-1998 (p<0.001) (15.0 and 12.5 years in males; 11.9 and 10.4 in females, respectively). Conclusion/interpretation. During a 16-year period the incidence of Type I diabetes did not increase in the 0-34 years age group in Sweden, while median age at diagnosis decreased. A shift to younger age at diagnosis seems to explain the increasing incidence of childhood Type I diabetes. [Diabetologia (2002) 45:783-791]

Can we slow the rising incidence of childhood-onset autoimmune diabetes? The overload hypothesis

“…In Sweden, a nationwide prospective register found no increase in young adults aged 15-34 years, and analysis of cumulative rates indicated a shift towards a younger age of onset rather than an overall rise in type 1 diabetes, at least up to the age of 35 [4]. Similar results were reported from Belgium [5].…”

The ‘accelerator hypothesis’: relationship between weight, height, body mass index and age at diagnosis in a large cohort of 9,248 German and Austrian children with type 1 diabetes mellitus

“…A shift to an early onset of type 1 diabetes, rather than a true increase in the incidence of the disease, can be seen [24,25]. Only 7.5% of our patients were in the 15-20-years age category, which may be the result of lower incidence rates or incomplete retrieval [26].…”

Birthweight and risk of type 1 diabetes in children and young adults: a population-based register study

“…Birthweight [5], as well as the prevalence of overweight children [7], has gradually increased in Sweden over recent decades. This trend seems to parallel the increasing incidence of type 1 diabetes occurring in childhood, especially in the younger age-at-onset groups, but is not seen in age groups older than 15 years at diagnosis [7].…”

“…The increase in overall growth of children as reflected by increments in height and weight would accelerate an already ongoing autoimmune destruction of beta cells by increasing the need for insulin [6]. Interestingly it has been shown that the incidence of type 1 diabetes is not increasing, but rather decreasing among young adults in Sweden [7]. Therefore the changing incidence over time would reflect an earlier onset rather than a total increase in occurrence of the disease at least up to the age of 35 years.…”