Type 2 diabetes is defined as diabetes which occurs due to insulin resistance rather than absolute insulin deficiency. In other words the beta cells of the pancreas continue to produce insulin, though the amount is inadequate as the cells of the body are not very sensitive to insulin. Worldwide it is estimated that over 100 million people have type 2 diabetes and over 90% of these have type 2 diabetes. It is therefore the 'common' form of diabetes. It is also a disease of older people and increasing numbers of patients are seen in ageing populations.
Type 2 diabetes is strongly linked with overweight, sedentary lifestyle and excess intake of high calorie or energy-rich foods. It is also associated more commonly with high blood pressure and abnormalities of blood fats such as cholesterol which together give a high risk of cardiovascular disease (heart attacks, strokes and circulatory problems in the legs). Over 75 % of people with type 2 diabetes die of these conditions and it is estimated that life expectancy is reduced by 5-10 years.
In the United Kingdom there are currently over 1.2 million people with type 2 diabetes, with a further 1 million thought to be undiagnosed as yet. It is clearly a major health problem and account for approximately 9% of the total NHS health budget.
There are many factors, some of them genetic, others environmental which are thought to contribute your chance of getting type 2 diabetes. There is strong evidence for a genetic link, as between 60-100 % of identical twins share this condition whereas less than 20 % of non-identical twins would be 'concordant' (both twins affected).
Being overweight, is now a major problem of lifestyle in western societies. In the UK more than half of adults are considered to be overweight. It must be emphasised however, that most obese people do not develop diabetes and not all individuals with type 2 diabetes are obese!
Lack of exercise is the other important 'environmental' factor in the development of obesity and it has been shown that people who exercise regularly are more sensitive to insulin.
The symptoms of type 2 diabetes are exactly the same as those encountered in type 1 disease and have been described in the accompanying leaflet Type 1 Diabetes.
Further information can be found in the leaflet What is Diabetes?
Type 2 diabetes was described in the past as 'mild' diabetes as it could often be managed by diet alone and did not require insulin. It is now recognised as a serious condition with profound complications if untreated. Much of the morbidity (sickness) associated with type 2 diabetes stems from the associated cardiovascular problems.
Complications of T2D may be divided into two main groups - the vascular problems and the other complications of diabetes which are due to the metabolic effects of diabetes. They are listed below and described in detail elsewhere.