Type 1 diabetes (or insulin-dependent) develops when the immune system in the body attacks insulin-producing beta cells in the pancreas and destroys them. When the pancreas no longer makes insulin, blood glucose (blood sugar) cannot enter the cells to be used for energy, leaving high levels in the blood.

Although type 1 is most often diagnosed in children and young adults under 30, people can develop type 1 at any age. An autoimmune reaction occurs that is caused by unknown environmental factors. The immune system attacks the beta cells of the pancreas, which produce insulin. People with type 1 cannot produced insulin and so are treated with injections of insulin.

Modern medicine has advanced the care of people with type 1 diabetes with various insulins and other medicines, devices to test blood glucose (glucose meters), insulin pumps, and continuous glucose monitoring systems.

Learn much more about type 1 diabetes in our "Type 1 Diabetes" section.

Reviewed by Clara Schneider MS, RD, RN, CDE, LDN - 05/13