What is Type 2 Diabetes?

What is Diabetes?

Between 2017-2018, 3.8 million people have been diagnosed with diabetes in the UK with Type 2 Diabetes Mellitus (T2DM) being the most prevalent.(2) As a growing epidemic, Type 2 Diabetes accounts for 90% of diabetics costing the NHS at least £10 billion yearly.(4)

Diabetes is a chronic metabolic disorder, associated with high levels of glucose in the bloodstream. When food is digested, carbohydrates and sugars are broken down into glucose via the digestive system. Glucose is an important energy fuel for organs in the body. The hormone insulin is secreted by beta cells located in the pancreas and is responsible for the regulation and uptake of glucose. T2DM is characterised by insulin resistance or insufficient insulin production, resulting in hyperglycaemia. (1) This is the build-up of glucose in the blood meaning body cells cannot obtain glucose to be stored and used for energy.

What are the causes of Diabetes?

There is a combination of major factors that contribute to the development of Type 2 Diabetes. This includes:

1. Age – Type 2 Diabetes is most commonly found in people older than 45 years however over recent years adolescents and younger adults are increasingly at risk. (3)

2. Ethnicity – T2DM is six times more common in people of South Asian descent. It is up to three times more common among people of African and African-Caribbean origin.

Figure 1: According to the Health Survey for England 2004, studies show the likelihood to develop T2DM for men and women amongst different minority ethnic groups.(7)

3. Obesity – The strongest association with T2DM is Obesity. Obesity is responsible for 80 to 85% of someone’s risk of the condition. A person with a body mass index (BMI) of 30 or more has a high risk of developing T2DM.(5)

4. Genetics – A child has a 1 in 3 chance of developing the condition if their parent is type 2 diabetic.(5)

5. Prediabetes – Pre-diabetic state is a condition where blood glucose levels are high but not high enough to be diagnosed as T2DM. This can be known as impaired fasting glycaemia (IFG) or impaired glucose tolerance (IGF).(6)Normal blood glucose levels should range between 4 -8 mmol/L however if this exceeds to 11mmol/L this could indicate impaired glucose tolerance is present.

6. Unhealthy lifestyle – This includes excessive alcohol consumption, smoking, lack of physical activity and poor diets which can trigger T2DM.

What are the symptoms of Diabetes and how is it diagnosed?

The classic symptoms comprise of:

  1. Polydipsia – excessive thirst
  2. Polyuria – frequent urination
  3. Fatigue
  4. Increased hunger
  5. Blurred Vision

In T2DM these symptoms are milder and tend to develop gradually making it difficult to identify it as an underlying illness. Early diagnosis is important as complications can arise 5-6 years prior to diabetes diagnosis. In addition, 6 in 10 people show no symptoms when they are diagnosed.(4) The most common test in place for Type 2 Diabetes is the Haemoglobin BA1C test (HbA1C). If not diagnosed early, type 2 diabetes has many irreversible health complications reducing life expectancy up to 10 years.(7)

What health problems can arise from Diabetes?


Every week diabetes causes more than 530 heart attacks and 680 strokes.(4)Cardiovascular disease is a primary cause of mortality and morbidity in both prediabetes and T2DM. There is a twofold increased risk of Cardiovascular disease (CVD), angina, heart failure and stroke for diabetics. This is caused by damaged blood and nerve vessels as the blood glucose is poorly controlled. The longer you have diabetes the higher the chances you will develop heart disease. The same lifestyle factors that affect Type 2 Diabetes such as poor diet, smoking, obesity are the same factors increasing the chances of CVD.

Figure 2: Two year prevalence showing diabetic complications during a two year period in England and Wales (from 1 April 2010 to 31 March 2012).(9)


Neuropathy is a type of nerve disorder caused by long term high blood glucose levels. The most common Diabetic neuropathy is sensory which affects the nerves detecting touch and temperature e.g. hands/feet. The second most common type is known as Autonomic affecting nerves controlling involuntary functions e.g. digestion. Diabetics suffering from nerve and blood vessel damage are 20 times more likely to experience an amputation.(4)


Diabetes retinopathy is responsible for 5% of all sight loss in the UK.(4) If blood glucose is not regulated you at a higher risk of suffering from glaucoma and cataracts. Glaucoma affects the nerve that connects the eyes to the brain. Cataracts affect the lens of the eye which provides clear and sharp visions. The short term effect is blurred vision however the long term effect is much serious resulting in microvascular damage to the vessels in the retina. As the retina is a highly vascular region in the eye, if damaged it can cause a haemorrhage thus obstructing the light passing through the retina. (8)

What are the treatments for Diabetes? How is it preventable?

In 2012/13 42.5 million items were prescribed to treat diabetes, £764 million was spent on drugs to treat diabetes in primary care.(10) It is clear that in current society, drugs such as metformin is used as the first line therapy to treat T2DM without considering the serious side effects. For example, medications containing SGLT2 inhibitors may promote urinary tract infections.(11)Although it has been proven effective in increasing insulin sensitivity there are other inexpensive alternatives. More than half of all cases of T2DM can be prevented or delayed simply by changing lifestyle factors.(4) The most appropriate line of treatment should be a combination of a healthy diet with adequate exercise. Aerobic exercise for duration of 90 to 150 minutes per week is beneficial as it can contribute to reducing the development of T2DM by 30 – 50 %.(3)(8)  Two studies have shown exercise plus diet interventions reduced the risk of diabetes and aided in reducing systole and diastole blood pressure levels.(12)  To prevent T2DM, studies support having a Mediterranean diet comprising of vegetables, legumes, nuts and whole grains to be effective.(13) An example of a healthy diet are foods low in refined carbohydrates and high in fibre.

In conclusion, almost 80% of the money the NHS spends on diabetes is on treating complications but this can be avoided via lifestyle adjustments.(4) Even though diets are variable according to availability, allergies and preferences, small modifications can be set in place to overall improve the quality of life.

Reference List:

  1. Olokoba,B, Obateru,O.A, Olokoba L.B, 2012. Type 2 Diabetes Mellitus: A Review of Current Trends. [Internet]. 2012 [cited 9 December 2019];. Available from: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3464757/
  2. Diabetes Prevalence 2018 [Internet]. Diabetes UK. 2019 [cited 1 December 2019]. Available from: https://www.diabetes.org.uk/professionals/position-statements-reports/statistics/diabetes-prevalence-2018
  3. Goyal R, Jialal I. Diabetes Mellitus Type 2 [Internet]. Ncbi.nlm.nih.gov. 2019 [cited 9 December 2019]. Available from: https://www.ncbi.nlm.nih.gov/books/NBK513253/
  4. Us, diabetes and a lot of facts and stats [Internet]. Diabetes.org.uk. 2019 [cited 13 December 2019]. Available from: https://www.diabetes.org.uk/resources-s3/2019-02/1362B_Facts%20and%20stats%20Update%20Jan%202019_LOW%20RES_EXTERNAL.pdf
  5. Type 2 diabetes symptoms and treatments [Internet]. Nhsinform.scot. 2019 [cited 13 December 2019]. Available from: https://www.nhsinform.scot/illnesses-and-conditions/diabetes/type-2-diabetes#causes-of-type-2-diabetes
  6. Impaired Glucose Tolerance [Internet]. Diabetes.co.uk. 2019 [cited 13 December 2019]. Available from: https://www.diabetes.co.uk/impaired-glucose-tolerance.html
  7. Diabetes in the UK 2010: Key statistics on diabetes [Internet]. Diabetes.org.uk. 2019 [cited 13 December 2019]. Available from: https://www.diabetes.org.uk/resources-s3/2017-11/diabetes_in_the_uk_2010.pdf
  8. W, Yanping.D, Yoshimasa.T and Wen. Z. 2014., Risk Factors Contributing to Type 2 Diabetes and Recent Advances in the Treatment and Prevention. NCBI [Internet]. 2014 [cited 13 December 2019];. Available from: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4166864/
  9. Adult obesity and type 2 diabetes [Internet]. Assets.publishing.service.gov.uk. 2019 [cited 13 December 2019]. Available from: https://assets.publishing.service.gov.uk/government/uploads/system/uploads/attachment_data/file/338934/Adult_obesity_and_type_2_diabetes_.pdf
  10. Action for Diabetes [Internet]. England.nhs.uk. 2019 [cited 13 December 2019]. Available from: https://www.england.nhs.uk/rightcare/wp-content/uploads/sites/40/2016/08/act-for-diabetes-31-01.pdf
  11. Type 2 diabetes symptoms and treatments [Internet]. Nhsinform.scot. 2019 [cited 13 December 2019]. Available from: https://www.nhsinform.scot/illnesses-and-conditions/diabetes/type-2-diabetes#treating-type-2-diabetes
  12. Orozco. LJBuchleitner AMGimenez-Perez GRoqué I Figuls MRichter BMauricio D. 2008.11. Exercise or exercise and diet for preventing type 2 diabetes mellitus. NCBI [Internet]. 2019 [cited 13 December 2019];. Available from: https://www.ncbi.nlm.nih.gov/pubmed/18646086
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