type 1 diabetes mellitus, an autoimmune disease characterized by inability to metabolize fuels, carbohydrates, protein, and fat because of absolute insulin deficiency. Type 1 diabetes can occur at any age, but its incidence is more common in children. Uncontrolled type 1 diabetes is characterized by excessive thirst, increased urination, increased desire to eat, loss of weight, ketoacidosis, diminished strength, and marked irritability. The clinical onset is usually rapid, but approximately one third of patients have a remission within 3 months (honeymoon phase). This stage may continue for days or months, but type 1 diabetes then progresses quickly to a state of total dependence on insulin. Persons with type 1 diabetes can manage their condition with a carbohydrate-controlled meal plan, exercise, and insulin. Evidence suggests that type 1 diabetes may be triggered by environmental factors, such as a viral infection in genetically susceptible individuals. Compare type 2 diabetes mellitus. Formerly called juvenile diabetes. See also diabetes mellitus.
