Figure 1. Natural history of type 1 diabetes and opportunities for T1D prevention.

The natural history of T1D has four main stages: 1. genetic predisposition, 2. prediabetes or autoimmunity, 3. clinical disease onset, and 4. development of diabetic complications. Primary prevention may be applied to the transition from genetic predisposition to autoimmunity. Primary prevention strategies should be highly effective, low-cost and no side effect and can be applied to large numbers of individuals that have increased genetic risk. Secondary prevention can be applied to prediabetic subjects with islet antibodies and the strategies of secondary prevention should be effective and moderate-cost (for example: antigen-based immunization and immunosuppressive drugs). Tertiary prevention is mainly applied to T1D patients with high risk for diabetic complications and the strategies of this step should be effective and reasonable-cost.