Diabetes is a disease that occurs when your blood glucose, also called blood sugar, is too high. Blood glucose is your main source of energy and comes from the food you eat. Insulin, a hormone made by the pancreas, helps glucose from food get into your cells to be used for energy.
Type 1 diabetes is a condition in which your immune system destroys insulin-making cells in your pancreas. These are called beta cells. The condition is usually diagnosed in children and young people, so it used to be called juvenile diabetes.
A condition called secondary diabetes is like type 1, but your beta cells are wiped out by something else, like a disease or an injury to your pancreas, rather than by your immune system.
Both of these are different from type 2 diabetes, in which your body doesn’t respond to insulin the way it should.