**7. Summary**

Data on the epidemiology of type 1 diabetes are based on standardized registry data, such as the Diabetes Mondiale (DIAMOND) Project worldwide and The Epidemiology and Prevention of Diabetes (EURODIAB) study in Europe. Some countries provide national registers. Regional or loco-regional registers as well as (cross-sectional) studies have added further data to the current knowledge. Epidemiologic data from developing countries are scarce and may not be fully rep‐ resentative.

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The incidence of type 1 diabetes varies up to 100-fold among different countries. The highest inci‐ dences are found in northern countries, especially Finland. The lowest incidence rates were re‐ corded in South American and Asian countries. When discussing type 1 diabetes incidence, also strong variations within countries have to be regarded and care should be taken when generaliz‐ ing results from a regional sample to a general population. The incidence of type 1 diabetes in‐ creases worldwide exponentially. The mean of increment is 3.0% per year. Some assume that the incidence of type 1 diabetes in 2020 will be twice that of the year 2000. Before the age of puberty type 1 diabetes there is no sex-related difference in the incidence of type 1-diabetes. However some early childhood risk factors show different odds for boys and girls and after puberty males are more frequently affected by new onset of type 1 diabetes than females. Type 1 diabetes inci‐ dence increases with the age of the children/adolescents, but the annually increase of incidence is higher in younger children and those with moderate genetic susceptibility. There is evidence for a circannular variation with a peak of type 1 diabetes incidence during the winter months. Possi‐ ble effects of the season of birth have to be further investigated with attention to the genetic back‐ ground of assessed individuals. Genetic susceptibility explains some of the variation of type 1 diabetes incidence and prevalence with the highest risk in individuals with Caucasian or Latino background. As supported by migration studies, the increasing incidence of type 1 diabetes illus‐ trates the importance of environmental risk factors as triggers of the disease.

Future research should focus on indentifying environmental and genetic risk factors of type 1 diabetes and its complications, preventive strategies and causal treatment options. The preva‐ lence, which doubled worldwide over the last decades, will increase further and type 1 diabetes will shift more and more into the focus of general practitioners. It becomes conclusive that type 1 diabetes will be a burden for more and more patients and for the majority of health care systems.
