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Type 2 diabetes

Key points

  • About 2.9 million people in the UK have diabetes – 85 in every 100 of these people have type 2 diabetes.
  • Type 2 diabetes is a lifelong condition and usually affects people over the age of 40.
  • Type 2 diabetes occurs when your body can't produce enough insulin or doesn’t respond to insulin as it should.
  • Symptoms include needing to pass urine frequently, feeling constantly thirsty and unexplained weight loss.
  • Eating a healthy diet, stopping smoking and reducing alcohol intake can help you manage type 2 diabetes.

Video: About type 2 diabetes

Type 2 diabetes is a lifelong condition in which your body can’t control the level of glucose in your blood. It develops when your body can’t make enough insulin or doesn't respond to it properly.

Animation: How type 2 diabetes develops

About type 2 diabetes

About 2.9 million people in the UK have been diagnosed with diabetes. There are two main types of diabetes: type 1 and type 2. Type 2 diabetes is the common form, affecting 85 out of every 100 people (including children) with diabetes. You may also hear type 2 diabetes called non-insulin-dependent diabetes and sometimes adult-onset or late-onset diabetes. However, this is misleading as type 2 diabetes is becoming more common in young adults and children.

Type 2 diabetes usually affects people over the age of 40, but can develop at any age. People of African-Caribbean or South Asian origin are more likely to develop the condition. It usually affects them earlier in life, from the age of about 25.

Type 2 diabetes develops when your body can’t produce enough insulin or doesn’t respond to insulin as it should. This happens if your body becomes less sensitive to insulin and doesn’t react to it properly (insulin resistance).

Insulin is important because it regulates the level of glucose in your blood. Glucose is a simple form of sugar found in foods and sugary drinks. It’s absorbed by your body as a natural part of digestion and is carried around your body in your blood. When glucose reaches your body tissues, such as muscle cells, insulin helps it enter the cells where it's converted into energy.

Insulin is produced by your pancreas, which is a gland located behind your stomach. If your pancreas doesn’t produce enough insulin, or your tissue cells don't respond properly to insulin, glucose can build up in your blood. This causes your blood sugar levels to rise.

Pancreas and ducts

Symptoms of type 2 diabetes

Many people with type 2 diabetes have no obvious symptoms. It's often discovered during a routine medical check-up with your GP. If you think you may be at risk of type 2 diabetes, speak to your GP. He or she may offer you a screening blood test to check for signs of the condition.

If you do have symptoms of type 2 diabetes, you may:

  • pass urine more often than usual
  • be constantly thirsty
  • have unexplained weight loss
  • be extremely tired
  • have blurred vision
  • have itchy skin around your genitals or get regular infections, such as thrush

If you have any of these symptoms, see your GP.

Complications of type 2 diabetes

Persistently high blood glucose levels due to uncontrolled diabetes can increase your risk of complications, which can include:

  • heart disease – diabetes is the second most common cause after smoking
  • stroke – people with diabetes are up to three times more likely to have a stroke than those without diabetes
  • nerve damage
  • periodontal disease
  • persistent or regular infections, such as skin, chest or urinary infections
  • kidney failure
  • blindness

In the long-term, type 2 diabetes can lead to complications even with good control of blood glucose.

If too much sugar builds up in your blood, you may develop hyperglycaemia. This may happen because you missed a dose of insulin or another medicine. You could also develop hyperglycaemia if, you have eaten more carbohydrate than usual or if you have an infection. Symptoms of hyperglycaemia include:

  • needing to pass urine frequently
  • feeling more thirsty and hungry than usual
  • feeling tired or weak

Very rarely, if you have an infection or become dehydrated, your blood glucose can rise to dangerously high levels. This can lead to a condition called hyperosmolar hyperglycaemic state. If this happens, you may become drowsy and lose consciousness. Although the risk of this condition is low, it is a medical emergency and you will need to be treated in hospital.


Your blood glucose levels can become too low (hypoglycaemia) if you don't eat enough carbohydrate while taking insulin or particular medicines called sulphonylureas (eg gliclazide). You’re more likely to develop hypoglycaemia if you take other medicines such as beta-blockers, drink too much alcohol or do more physical activity than usual. Hypoglycaemia can cause you to feel faint, sweaty, confused and you may feel your heart pounding. You can treat it straight away by eating glucose tablets (or a few sweets or a sugary drink), followed by a couple of biscuits or a sandwich.

Causes of type 2 diabetes

There are several risk factors that make you more likely to develop type 2 diabetes, including:

  • being overweight or obese – in particular, if you’re an 'apple shape' with lots of fat around your abdomen (tummy)
  • having a close family member with the condition
  • being of African-Caribbean or South-Asian origin
  • being over 40 – your risk increases with age
  • having high blood pressure or heart disease
  • not exercising regularly
  • smoking
  • being a woman with polycystic ovary syndrome
  • being a woman and having had diabetes that developed during pregnancy (gestational diabetes)
  • having a condition such as impaired glucose tolerance or impaired fasting glycaemia – where your blood sugar levels are naturally higher than normal

Diagnosis of type 2 diabetes

Your GP will ask about your symptoms and examine you. He or she may advise you to have a blood test to examine the levels of glucose in your blood. Your GP may also suggest that you have the following tests.

  • Fasting blood glucose test. You will need to fast overnight before having this test. Glucose levels of 7.0mmol/litre or greater suggest you have type 2 diabetes.
  • Two-hour blood glucose test (glucose tolerance test). This measures how your blood glucose level changes over time after you have a sugary drink. You will need to fast overnight before having this test. Glucose levels of 11.1mmol/litre or greater suggest you have type 2 diabetes.
  • Glycosylated haemoglobin (HbA1C) test. HbA1C is a protein that is produced when you have high blood glucose levels over a long period of time. HbA1C levels of 48mmol/mol or greater suggest you have type 2 diabetes.

If your blood test results suggest you have type 2 diabetes, your GP may advise you to have repeat tests before your diagnosis is confirmed.

If you're diagnosed with type 2 diabetes, you may be referred to a clinic that has nurses and doctors who specialise in treating diabetes.

Treatment options for type 2 diabetes

There are a number of treatment options for type 2 diabetes, as described below. Which treatments you're offered will depend on your personal circumstances. Your doctor will discuss these with you to help you make a decision that is right for you. Your decision will be based on your doctor’s expert opinion and your own personal values and preferences.

There isn't a cure for type 2 diabetes but it can be controlled. Some people can control their condition with lifestyle changes alone. Others need to take medicines or have insulin injections.


By making the following lifestyle changes, you can help to control your blood glucose levels.

  • Eat a healthy, balanced diet with regular meals, three times a day. Include carbohydrates, such as pasta or potatoes, in each meal.
  • Aim to do 150 minutes of moderate exercise over a week in bouts of 10 minutes or more. This will help you to stay a healthy weight and control your blood glucose levels.
  • Only drink alcohol in moderation and stick within the recommended limits.
  • If you smoke, stop. Smoking is unhealthy for everyone, but it's especially important to stop if you have diabetes. This is because you already have an increased risk of developing circulatory problems and heart disease. Smoking further increases your risk of developing these conditions.

Ask at your clinic whether they run structured education classes. These aim to help you learn how to look after your condition and how to monitor it yourself.


If lifestyle changes alone don’t keep your blood glucose levels under control, your doctor may advise you to take medicines. There are many types of diabetes medicines available. Your doctor will usually begin by offering you a medicine called metformin.

Metformin works by reducing the amount of glucose that gets released into your blood from your liver. It also improves the way glucose is used by your muscles. If metformin doesn’t help you reach your desired blood glucose levels within three months, there is a range of medicines that your doctor can offer you instead. The one that you’re offered will depend on many things but some of the possible medicines include the following. 

  • Insulin secretagogues help your pancreas to produce more insulin. Sulphonylurea medicines are a commonly used insulin secretagogue – examples include gliclazide, glipizide and glimepiride.
  • A type of medicine called a DPP-4 inhibitor (such as sitagliptin, saxagliptin or linagliptin) help your body to produce insulin when it’s needed.
  • GLP-1 agonists, such as exenatide or liraglutide. These medicines are given by injection and work by helping your body to make more insulin when it’s needed. They can also reduce your appetite and help you lose weight.
  • Pioglitazone helps to reduce insulin resistance. However, it’s less commonly used now as there are concerns that it may increase the risk of bladder cancer.

For more information about medicines for type 2 diabetes, speak to your doctor or diabetes specialist nurse.

Insulin injections

If lifestyle changes and medicines can’t keep your blood glucose levels under control, your doctor may suggest you have insulin injections.

You will usually inject yourself with insulin once or twice a day, using either a small needle or a pen-type syringe with replaceable cartridges. There are several different types of insulin that work at different rates and for different lengths of time. Ask your doctor for advice on which type is best for you.

If you have insulin injections, you will be advised to monitor your blood glucose levels with a home test kit. This involves taking a pinprick of blood from your finger and putting a drop on a testing strip. A meter will read the result automatically.

Your 'normal' blood glucose range will be specific to you but a general guide for adults with type 2 diabetes is:

  • before meals: 4 to 7mmol/litre
  • after meals: less than 8.5mmol/litre (two hours after a meal) – however, this is less reliable than testing your blood sugar before eating

Your doctor, GP or diabetes specialist nurse will show you how to monitor your blood glucose levels and tell you how often you need to check it.

Monitoring your blood glucose level

Your doctor may advise you to have your levels of HbA1C tested at least once a year. HbA1C is a measure of how well you’re controlling your blood sugar levels over the long term. The test is done by taking blood from a vein in your arm or sometimes a drop of blood from a fingerprick.

You will usually be offered at least one full review of your condition every year.


Reviewed by Pippa Coulter, Bupa Health Information Team, June 2013.

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For answers to frequently asked questions on this topic, see FAQs.

For sources and links to further information, see Resources.

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  • This information was published by Bupa's Health Information Team and is based on reputable sources of medical evidence. It has been reviewed by appropriate medical or clinical professionals. Photos are only for illustrative purposes and do not reflect every presentation of a condition. The content is intended only for general information and does not replace the need for personal advice from a qualified health professional. For more details on how we produce our content and its sources, visit the about our health information page.

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