Diabetes mellitus, more simply called diabetes, is a serious, long-term (or "chronic") condition that occurs when there are raised levels of glucose in a person's blood because their body cannot produce any or enough of the hormone insulin, or cannot effectively use the insulin it produces.
Insulin is an essential hormone produced in the pancreas. It allows glucose from the bloodstream to enter the body's cells where that glucose is converted into energy. Insulin is also essential for the metabolism of protein and fat. A lack of insulin, or the inability of cells to respond to it, leads to high levels of blood glucose (hyperglycaemia), which is the clinical indicator of diabetes. The threshold levels for the diagnosis of diabetes can be found in Table 1.1.
Insulin deficit, if left unchecked over the long term, can cause damage to many of the body's organs, leading to disabling and life-threatening health complications such as cardiovascular diseases(CVD), nerve damage (neuropathy), kidney damage (nephropathy) and eye disease (leading to retinopathy, visual loss and even blindness). However, if appropriate management of diabetes is achieved, these serious complications can be delayed or prevented altogether.