Incidence of type 1 and type 2 diabetes in adults and children in Kronoberg, Sweden

All newly diagnosed diabetes in Kronoberg during 3 years was registered, with blood samples from 1630/1666 (97.8%) adults. Those positive for GADab and/or ICA and/or C-peptide < 0.25 nmol/L (0.7%) were classified as type 1 diabetes, the remaining as type 2. Incidence of type 1 in 0–19-year-olds was 37.8(36.1–39.6, 95%CI) and in 20–100 year-olds 27.1(25.6–27.4) per 100 000 and year, it was bimodal with equal peaks in 0–9 year-olds and in 50–80-year-olds. Adults had type 2 incidence 378 (375–380), children 3.1 (2.6–3.6). Among adults 6.9% had type 1 and 93.1% type 2. Among antibodypositive adults (n = 101), GADab were present in 90%, ICA in 71%, both GADab and ICA in 61%. Ophthalmology contact as second source was confirmed for 98%. There were no gender differences in type 1 in any age group, small ones in pediatric subgroups. In type 2 men predominated in ages above 40 years. Incidences of type 1 diabetes in both children and adults were very high and as high above age 50 years as in children. Incidence of type 2 was the highest reported from Sweden, to which new diagnostic criteria, a high degree of case-finding, and many elders, may have contributed, but results may also reflect a true increase in incidence of both types of diabetes.