Type 1 diabetes (T1D), formerly known as juvenile diabetes, is an autoimmune disease that originates when cells that make insulin (beta cells) are destroyed by the immune system.[4] Insulin is a hormone required for the cells to use blood sugar for energy and it helps regulate glucose levels in the bloodstream.[2] Before treatment this results in high blood sugar levels in the body.[1] The common symptoms of this elevated blood sugar are frequent urination, increased thirst, increased hunger, weight loss, and other serious complications.[4][10] Additional symptoms may include blurry vision, tiredness, and slow wound healing.[2] Symptoms typically develop over a short period of time, often a matter of weeks if not months.[1]The cause of type 1 diabetes is unknown,[4] but it is believed to involve a combination of genetic and environmental factors.[1] The underlying mechanism involves an autoimmune destruction of the insulin-producing beta cells in the pancreas.[2] Diabetes is diagnosed by testing the level of sugar or glycated hemoglobin (HbA1C) in the blood.[6][8] Type 1 diabetes can typically be distinguished from type 2 by testing for the presence of autoantibodies[6] and/or declining levels/absence of C-peptide.There is no known way to prevent type 1 diabetes.[4] Treatment with insulin is required for survival.[1] Insulin therapy is usually given by injection just under the skin but can also be delivered by an insulin pump.[11] A diabetic diet and exercise are important parts of management.[2] If left untreated, diabetes can cause many complications.[4] Complications of relatively rapid onset include diabetic ketoacidosis and nonketotic hyperosmolar coma.[6] Long-term complications include heart disease, stroke, kidney failure, foot ulcers and damage to the eyes.[4] Furthermore, since insulin lowers blood sugar levels, complications may arise from low blood sugar if more insulin is taken than necessary.[6]Type 1 diabetes makes up an estimated 5–10% of all diabetes cases.[9] although it is estimated that about 80,000 children develop the disease each year.[6] Within the United States the number of people affected is estimated at one to three million.