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Diabetes is a life-long health condition caused by excess levels of glucose in the blood

What is diabetes?

There are currently 3.5 million people diagnosed with diabetes in the UK, and an estimated 549,000 people who have the condition, but don’t know it (Diabetes UK, 2016). It is a lifelong condition that causes a person's blood sugar (glucose) level to become too high.

Whilst both type 1 and type 2 diabetes are characterised by having higher than normal blood glucose levels, the cause and development of the conditions are different.

Type 1 diabetes

Type 1 diabetes is an autoimmune disease which develops when the insulin-producing cells in the body have been destroyed and the body is unable to produce insulin. No one knows why this happens but the most likely reason is that the body has an abnormal reaction to the cells. This could be triggered by an infection or virus but again this is not known for sure. Type 1 diabetes is often referred to as insulin-dependent diabetes. It can develop at any age but usually appears before the age of 40, and especially in childhood. A person with type 1 diabetes will need to take insulin injections for life. They will also need to ensure that their blood glucose level stays balanced by eating a healthy diet, take regular physical activity and carry out regular blood tests. People with type 1 diabetes make up only 10% of all people with diabetes.  

Type 2 diabetes

Type 2 diabetes develops when the body can still produce some insulin but not enough for it to function properly, or when the cells in the body do not react properly to insulin. This is called insulin resistance. The treatment of type 2 diabetes centres on lifestyle management including a healthy diet, regular exercise and the person monitoring their blood glucose level. As the condition progresses over time oral therapies are used, however, if these do not prove to be an effective control then the person with diabetes may require insulin injections. There are several oral therapies for diabetes. Some help the body to use insulin more effectively whilst others increase the amount of insulin that the body produces.

Type 2 diabetes is often associated with obesity. Obesity-related diabetes is sometimes referred to as maturity-onset diabetes because it is more common in older people. However, it is also increasingly becoming more common in children, adolescents and young people of all ethnicities but is particularly prevalent in people of South Asian extraction. Type 2 diabetes is far more common than type 1 diabetes - around 90% of all adults in the UK with diabetes have type 2 diabetes.

Typical symptoms may include:

  • feeling very thirsty
  • passing urine more often than usual, particularly at night
  • feeling very tired
  • weight loss and loss of muscle bulk
  • losing weight without trying to
  • genital itching or thrush
  • cuts and wounds take longer to heal
  • blurred vision


A patient diagnosed with diabetes will need to take additional care of their health. They will need on-going advice and support about maintaining a healthy diet, keeping active and monitoring their health. Diabetes does not have to be a burden, people can live normal active and healthy lives and very small adjustments to their lifestyle can make significant improvements. Most diabetes management relies on a person 'self-managing' the condition so their motivation is a major key to effective treatment.


Although it isn’t actually a clinical term, pre-diabetes is often used to describe people who have an elevated risk of developing diabetes. It occurs when blood glucose levels exceed normal levels but do not climb high enough to warrant a diagnosis of diabetes. It can also be referred to as borderline diabetes, Impaired Glucose Tolerance (IGT), Impaired Fasting Glycaemia (IFG) and Impaired Glucose regulation (IGR).

If pre-diabetes is undiagnosed and untreated the person will almost certainly develop type 2 diabetes. It is estimated that a third of adults in England have pre-diabetes (Diabetes UK, 2014).  Many people often don't know that they have it until it is too late as there are sometimes no noticeable symptoms.

Pre-diabetes is closely linked to obesity and other poor lifestyle choices, and is putting an increasing burden on the health care system. People diagnosed with pre-diabetes can slow down or prevent the condition from developing into type 2 diabetes by making lifestyle changes. The following are significant factors in the management of diabetes and should be discussed with each person:

  • healthy eating
  • keeping active
  • weight management
  • smoking cessation and alcohol consumption
  • emotional wellbeing.

Diagnosing diabetes

Diabetes UK supports the diagnostic criteria published by the World Health Organisation (WHO) in 2006: Definition and diagnosis of diabetes mellitus and intermediate hyperglycaemia. Diabetes UK also welcomed the 2011 decision by the WHO to accept the use of HbA1c testing in diagnosing diabetes: Use of glycated haemoglobin in the diagnosis of diabetes mellitus.

For more information on diagnostic criteria for diabetes, see: Diabetes UK: Diagnostic criteria for diabetes