Medicine. A group of disorders characterized by elevated blood sugar level (hyperglycemia) owing to insufficient secretion of insulin or to inability to use insulin.
Diabetes occurs in two major forms: diabetes type 1 is due to lack of insulin production by the beta cells of the pancreas and typically occurs in childhood. Diabetes type 2 is characterized by the inability of tissue to utilize sugar despite the availability of insulin. It is caused by overweight, energy-dense and high fat diet, and physical inactivity. Often there is a genetic predisposition.