Diagnosis: what is diabetes?

People with diabetes mellitus have a relative or total absence of insulin. Insulin is a hormone secreted by the beta cells of the Islets of Langerhans in the pancreas, a leaf shaped gland situated in the abdomen.

Diabetes presents in several different forms:

Type 1- (formerly called insulin dependant diabetes)
Type 2 – (formerly called non-insulin dependant diabetes)(most common accounts for about 90% of cases world wide)
Gestational Diabetes.
Other specific types (WHO 1999, pp25-30) (PDF, 1.7MB)

The two most common forms are

Type 1 diabetes:

This results from immunological selective beta cell destruction and people with this condition require insulin replacement by injection and are prone to ketoacidosis in a hyperglycaemic state.

"Type 1 includes those cases attributable to an autoimmune process, as well as those with beta cell destruction…..for which neither aetiology nor pathogenesis is known (idiopathic)" (WHO 1999, p11)

Type 2 diabetes:

This is a chronic, progressive disorder associated with "defect(s) in insulin secretion almost always with a major contribution from insulin resistance" (WHO 1999 p.11) and is a marker for cardiovascular disease.

Gestational Diabetes:

Carbohydrate intolerance of variable severity with onset and first recognition during pregnancy.

MODY

This stands for Maturity Onset Diabetes of the Young. It is not the same as type 2 diabetes in children, it is a genetic form of diabetes that passes down every generation. For further information please see Diabetesgenes.org.