What is diabetes?

The definition of diabetes, its causes, complications, and basic treatments are outlined. Diabetes mellitus is characterized by increased concentrations of glucose in the blood. The basic defect is a relative or absolute lack of insulin, the pancreatic hormone promoting the transfer of glucose into tissues for storage as glycogen or fat. Type 1 diabetes is due to autoimmune destruction of insulin-producing cells and insulin therapy is essential. Type 2 diabetes is due to a relative lack of insulin, often with tissue insulin resistance. It is a slowly progressive condition so that, although diet and lifestyle changes are often effective initially, oral therapy and insulin may be required eventually. Diabetes is associated with long-term vascular complications affecting both small and large arteries.