A chronic metabolic disease, characterized by abnormally high blood sugar (glucose) levels, resulting from the inability of the body to produce or respond to the hormone insulin (glucose resistance), causing cells in the liver, muscle, and fat tissue to take up glucose from the blood. 

‘Type 1 diabetes mellitus’, formerly known as insulin-dependent or juvenile-onset diabetes (IDDM), is usually the result of autoimmune destruction of the insulin secreting beta-cells of the pancreas.

The most common form of diabetes is ‘type 2 diabetes mellitus’, formerly known as non-insulin-dependent or adult onset diabetes (NIDDM), which develops when the tissues of the body become less sensitive to insulin secreted by the pancreas.