The overall purpose of our research is to investigate etiology, prediction, and prevention of pediatric autoimmune diabetes (type 1 diabetes) and other autoimmune diseases. Type 1 diabetes is preceded by an immune-mediated destruction of the pancreatic islet beta cells resulting in loss of insulin production. Genetic factors confer susceptibility and help us identify children at risk, while other still undefined factors are needed to trigger the autoimmune process or accelerating beta-cell destruction. The autoimmune process often starts early in life and can be predicted by islet autoantibodies and in late stages by metabolic changes. Other autoimmune diseases, such as thyroid autoimmune disease, share similarities and often coincide with type 1 diabetes. Our research is focused on longitudinal studies on etiological triggers or accelerating factors and refined possibilities of prediction as well as clinical studies on primary or secondary prevention.