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Diabetes, type 2

Page last reviewed: 13/07/2011

Diabetes is a long-term (chronic) condition caused by too much glucose, a type of sugar, in the blood. It is also sometimes known as diabetes mellitus.

Diabetes is estimated to affect about 200,000 people in Ireland.

How does diabetes occur?

Normally, the amount of sugar in the blood is controlled by a hormone called insulin. Insulin is produced by the pancreas, a gland located behind the stomach. When food is digested and enters the bloodstream, insulin helps move any glucose out of the blood and into cells, where it is broken down to produce energy.

In people with diabetes, the body is unable to break down glucose into energy. This is because there is either not enough insulin to move the glucose, or because the insulin that is there does not work properly.

There are two types of diabetes: type 1 diabetes and type 2 diabetes. This article focuses on type 2 diabetes.

What is type 2 diabetes?

Type 2 diabetes occurs when not enough insulin is produced by the body for it to function properly, or when the body's cells do not react to insulin. This is called insulin resistance.

Type 2 diabetes is far more common than type 1 diabetes, which occurs when the body does not produce any insulin at all. Around 90% of all adults with diabetes have type 2 diabetes.

If you have type 2 diabetes, you may be able to control your symptoms simply by eating a healthy diet. However, as type 2 diabetes is a progressive condition, you may eventually need to take medication,usually talets or injections to control your blood glucose levels.

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.

Chronic usually means a condition that continues for a long time or keeps coming back.
Glucose (or dextrose) is a type of sugar that is used by the body to produce energy.
Insulin is a hormone released by the pancreas that helps the body to control blood sugar levels.

Obesity is when a person has an abnormally high amount of body fat.


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Page last reviewed: 13/07/2011

Many people have type 2 diabetes for years without knowing it because they may have no symptoms of diabetes.

It is important to get medical advice if you think you have signs of diabetes. Early diagnosis and treatment can reduce your risk of developing complications later.

The main symptoms of diabetes are:

  • feeling very thirsty
  • going to the toilet a lot, especially at night
  • extreme tiredness
  • weight loss and loss of muscle bulk

Other symptoms of diabetes can include:

  • itchiness around the vagina or penis
  • recurring thrush as a result of the excess glucose in your urine
  • blurred vision caused by the lenses of your eyes becoming very dry
  • cuts and sores taking longer to heal

Not everyone will experience these other symptoms, and they are not usually severe in those who do get them.

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Glucose (or dextrose) is a type of sugar that is used by the body to produce energy.
Insulin is a hormone released by the pancreas that helps the body to control blood sugar levels.

Page last reviewed: 13/07/2011

Insulin is a hormone that is needed to control the amount of glucose, a type of sugar, in your blood. When you eat, your digestive system breaks down your food to release the nutrients from it. These nutrients, including glucose, enter your bloodstream. Normally, insulin is produced by your pancreas to move the glucose from your blood into your cells, where it is broken down to produce energy.

Type 2 diabetes occurs because your body cannot produce enough insulin or because the cells in your body do not react properly to insulin.

Risk factors for type 2 diabetes

The exact cause of type 2 diabetes is not fully understood, although there are many factors that make developing the condition more likely. You are more likely to develop type 2 diabetes if:

  • You have a relative with type 2 diabetes.
  • You are of South Asian, African-Caribbean or Middle Eastern descent.
  • You are overweight or obese.   
  • You are over 40.
  • You have had gestational diabetes
  • You have polycystic ovary syndrome

Genetic factors

You are more likely to get type 2 diabetes if you have a close relative, such as a parent, brother or sister, who has it. The closer the relative, the greater the risk.

Ethnic origin

People of South Asian, African, African-Caribbean and Middle Eastern descent are more likely to develop type 2 diabetes. People of African-Caribbean or South Asian origin are also more likely to develop complications of diabetes, such as heart disease, at a younger age than the rest of the population.

Being overweight or obese

If you are overweight or obese, you are at greater risk of developing type 2 diabetes. Fat around your abdomen (belly), sometimes called active fat, puts you at greater risk of type 2 diabetes than fat elsewhere. This is because it releases chemicals that can upset the cardiovascular and metabolic systems of the body. This can put you at higher risk of a number of conditions including heart disease, stroke and some cancers.

A quick way to assess your diabetes risk is to measure your waist. This is a measure of abdominal obesity, a particularly high-risk form of obesity. When you have excess weight around your middle, you are at high risk of developing diabetes.

Women are thought to be at a higher risk of developing type 2 diabetes if they have a waist size of 31.5 inches (80cm) or over. Men are thought to be at a higher risk if they are Asian and their waist is 35 inches (90cm) or over, or if they are white or black with a waist size of 37 inches (94cm) or over.

If you lose about 5% of your body weight and take regular exercise, you could reduce your risk of getting diabetes by over 50%.


Your risk of developing type 2 diabetes also increases as you get older. This may be because people usually gain weight and exercise less as they get older.

You are considered to be at risk of developing type 2 diabetes if you are over 40 years of age and white, or over 25 years of age and black, Asian or from a minority ethnic group. However, some children as young as seven are now being diagnosed with type 2 diabetes.

Other factors

You also have an increased risk of developing type 2 diabetes if you have either impaired fasting glycaemia (IFG) or impaired glucose tolerance (IGT). These conditions are sometimes also known as pre-diabetes and mean that your blood glucose level is higher than usual, but not high enough to cause diabetes. IFG and IGT can both progress to type 2 diabetes if you do not take steps to prevent it.

Women who experienced gestational diabetes during pregnancy are also at higher risk of developing diabetes in later life.

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Glucose (or dextrose) is a type of sugar that is used by the body to produce energy.
Insulin is a hormone released by the pancreas that helps the body to control blood sugar levels.

Page last reviewed: 13/07/2011

It is important to diagnose diabetes as early as possible so that treatment can be started. If you experience symptoms, see your GP as soon as possible.

Diagnosis of diabetes

A urine sample positive for glucose does not diagnose diabetes but may be an indicator that you have the condition as normally the urine does not contain glucose.

Diabetes is diagnosed using blood tests.  If you have symptoms of a high blood sugar then a random blood glucose sample may be sufficient to make the diagnosis.

If you don’t have symptoms of a high blood sugar then a fasting blood glucose sample taken in the morning or a sample used to measure a test called the IFCC (HbA1c), which is an indicator of your blood sugar levels over the preceding 8 to 12 weeks may be sufficient to make the diagnosis.

Very rarely in type 2 diabetes there is a test called the oral glucose tolerance test which is used to diagnose diabetes. You are given a sugary drink and your blood sugar is measured before and 2 hours after the drink.

Blood test
During a blood test, a sample of blood is taken from a vein using a needle, so it can be examined in a laboratory.
Glucose (or dextrose) is a type of sugar that is used by the body to produce energy.
Insulin is a hormone released by the pancreas that helps the body to control blood sugar levels.

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Page last reviewed: 13/07/2011

Treatment for diabetes aims to help people with the condition to control their blood glucose levels and minimise the risk of developing complications over time. If you are diagnosed with type 2 diabetes, you will need to look after your health carefully for life. This may seem daunting, but your diabetes healthcare team can offer support and advice about all aspects of your treatment.

Lifestyle modification

For many people who are diagnosed with type 2 diabetes, the first approach to treatment will be making changes to your lifestyle. These include taking regular exercise, eating a healthy diet and losing weight if you are overweight or obese. Doing this may be enough to keep your blood glucose at a safe and healthy level, without the need for other treatment.

Taking medicines

Type 2 diabetes usually gets worse over time. Even if they work at first, diet and exercise may not be enough to control your blood glucose levels.

If you have type 2 diabetes, you may need (or eventually need) medicines that reduce high levels of blood sugar. At first, this will usually be tablets, sometimes a combination of more than one type of tablet. It may also include injectable insulin.

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Monitoring blood glucose levels

Blood glucose testing (HbA1c)

If you have type 2 diabetes, your GP or diabetes healthcare team will need to take a reading of your long-term blood glucose level about every three to four months. This shows how stable your glucose levels have been in the recent past and how well your treatment plan is working.

The test that is used to measure your blood glucose levels over the previous 6-12 weeks is known as the HbA1c (IFCC) test. HbA1c is a form of haemoglobin, the chemical that carries oxygen in red blood cells, which also has glucose attached to it. This needs to be checked every three to four months. The HbA1c (IFCC) test will usually be less than 7.0% (53mmol/mol).

A high HbA1c level means your blood glucose level has been consistently high over recent weeks, and your diabetes treatment plan may need to be changed. Your diabetes healthcare team can help you set a target HbA1c level to aim for. This will usually be less than 53 mmol/mol HbA1c (7.0%). It can be as low as 48mmol/mol (6.5%) for some people.

Monitoring blood glucose levels yourself

As well as having your blood glucose level checked by a health professional every three to four months, you may also be given the opportunity to monitor your own blood glucose levels.

Even if you are being treated with tablets or insulin therapy and a healthy diet, many factors such as exercise, illness and stress can affect blood glucose levels. Other factors that may affect your blood glucose levels include drinking alcohol, taking other medicines and, for women, changes to hormone levels during the menstrual cycle.

Many people with diabetes monitor their blood glucose levels at home using a simple finger prick blood test.

In home testing, blood glucose levels are usually measured by how many millimoles of glucose are in a litre of blood. A millimole is a measurement used to define the concentration of glucose in your blood. The measurement is expressed as millimoles per litre, or mmol/l for short.

A normal blood glucose level is 4.0-6.0 mmol/l before meals (preprandial) and less than 10.0 mmol/l two hours after meals (postprandial), although this can very from person to person. Your diabetes healthcare team can discuss your blood glucose level in more detail with you.

Find out how to test your glucose levels.

Medicines for type 2 diabetes (glucose-lowering tablets)

If regular exercise and a healthy diet are not effective in controlling your blood glucose levels, you may need medicines to treat type 2 diabetes.

Several different types of medicine, usually taken as tablets, are used to treat type 2 diabetes. You may need to take a combination of two or more medicines to control your blood glucose level.


Metformin is often the first medicine that is recommended to treat type 2 diabetes. It works by reducing the amount of glucose that your liver releases into your bloodstream. It also makes your body's cells more responsive to insulin.

If you are overweight, it is likely that you will be prescribed metformin. Unlike some other medicines that are used to treat type 2 diabetes, metformin should not cause additional weight gain. However, it can sometimes cause mild side effects, such as nausea and diarrhoea and you may not be able to take it if you have kidney damage.


Sulphonylureas increase the amount of insulin that is produced by your pancreas. Examples of sulphonylureas include:

  • glibenclamide
  • gliclazide
  • glimerpirizide
  • glipizide
  • gliquidone

You may be prescribed one of these medicines if you cannot take metformin or if you are not overweight. You may be prescribed a sulphonylurea and metformin if metformin does not control blood glucose on its own.

Sulphonylureas can increase the risk of hypoglycaemia (low blood glucose) because they increase the amount of insulin in your body. Sulphonylureas may sometimes cause side effects including weight gain, nausea and diarrhoea.

Glitazones (thiazolidinediones, TZDs)

Thiazolidinedione medicines (pioglitazone) make your body's cells more sensitive to insulin so that more glucose is taken from your blood. They are not often used alone, but are usually used in addition to metformin or sulphonylureas, or both. They may cause weight gain, ankle swelling or bladder cancer. Do not take pioglitazone if you have heart failure or if you have a high risk of bone fracture.

 Gliptins (DPP-4 inhibitors)

Gliptins work by preventing the breakdown of a naturally occurring hormone called GLP-1. GLP-1 helps the body produce insulin in response to high blood glucose levels, but is rapidly broken down. By preventing this breakdown, the gliptins (sitagliptin, vildagliptin or saxagliptin) act to prevent high blood glucose levels, but do not result in episodes of hypoglycaemia. You may be prescribed a gliptin if you are unable to take sulphonylureas or glitazones. They are not associated with weight gain.

GLP-1 agonists

Liraglutide or Exenatide are injections given once or twice a day respectively which mimic the hormone GLP-1 produced by the gut.  Both boost insulin production, reducing blood glucose levels without the risk of hypoglycaemic episodes when used on their own.  Both injections also lead to modest weight loss in many people who use the injection.  It is mainly used in obese patients who are already on metformin.  Exenatide can also be given as an injection once a week.


Acarbose helps prevent your blood glucose level from increasing too much after you eat a meal. It slows down the rate at which your digestive system breaks carbohydrates down into glucose.

Acarbose is not often used to treat type 2 diabetes because it usually causes side effects, such as bloating and diarrhoea. However, you may be prescribed acarbose if you cannot take other types of medicine for type 2 diabetes.

Nateglinide and repaglinide

Nateglinide and repaglinide stimulate the release of insulin by your pancreas. They are not commonly used but may be an option if you have meals at irregular times. This is because their effects do not last very long, but they are effective when taken just before you eat.

Nateglinide and repaglinide can cause side effects, such as weight gain and hypoglycaemia (low blood glucose).

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Insulin treatment

If glucose-lowering tablets are not effective in controlling your blood glucose levels, you may need to have insulin treatment. Insulin treatment can be taken instead of or alongside your tablets, depending on the dose and the way that you take it.

Insulin comes in several different preparations and each works slightly differently. For example, some last up to a whole day (long acting), some last up to eight hours (short acting) and some work quickly but do not last very long (rapid acting).

Your treatment may include a combination of these different insulin preparations.

Insulin injections

In most cases of diabetes, you will need to have insulin injections. Insulin must be injected because if it were taken as a tablet, it would be broken down in your stomach, just like food, and wouldn't be able to enter the bloodstream.

If you need to take insulin by injection, your diabetes healthcare team will advise you about when you need to take it. They will show you how to inject it yourself. They will also give you advice about storing your insulin and disposing of your needles properly.

Insulin injections are given using either a syringe or an injection pen, which is also called an insulin pen (auto-injector). Most people need between two and four injections a day. Your GP or diabetes nurse will also teach one of your close friends or relatives how to inject the insulin properly.

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Treatment for hypoglycaemia (low blood glucose)

If you have type 2 diabetes that is controlled using insulin, you may experience episodes of hypoglycaemia. Hypoglycaemia can occur when your blood glucose levels become very low. Mild hypoglycaemia (a 'hypo') can make you feel shaky, weak and hungry, but it can usually be controlled by eating or drinking something sugary.

If you have a hypo, you should initially have a form of carbohydrate that will act quickly, such as a sugary drink or glucose tablets. This should be followed by a longer-acting carbohydrate such as a cereal bar, sandwich or piece of fruit. In most cases, these measures will be enough to raise your blood glucose level to normal, although it may take a few hours.

However, if you develop severe hypoglycaemia, you may become drowsy and confused, and you may even lose consciousness. If this occurs, you will need to have an injection of glucagon into your muscle. Glucagon is a hormone that quickly increases your blood glucose levels.

Your diabetes healthcare team can tell you how to avoid a hypo and what to do if you have one.

Other treatments

If you have type 2 diabetes, you have an increased risk of developing heart disease, a stroke and kidney disease. To reduce the chance of this, you may be advised to take other medicines which will reduce your risk, including:

  • anti-hypertensive medicines to control high blood pressure
  • a statin, such as simvastatin or atorvastatin, to reduce high cholesterol levels
  • low-dose aspirin to prevent a stroke
  • an angiotensin-converting enzyme (ACE) inhibitor, such as enalapril, lisinopril or ramipril, if you have the early signs of diabetic kidney disease

Diabetic kidney disease is identified by the presence of small amounts of albumin (a protein) in your urine. If it is treated early enough, diabetic kidney disease is often reversible.

Page last reviewed: 13/07/2011

If your diabetes is not treated, it can lead to many different health problems. Large amounts of glucose can damage blood vessels, nerves and organs. Even a mildly raised glucose level that does not cause any symptoms can have damaging effects in the long term.

Heart disease and stroke

If you have diabetes, you are up to five times more likely to have heart disease and a stroke than someone without diabetes. Prolonged, poorly controlled blood glucose levels increase the likelihood of atherosclerosis (furring and narrowing of the blood vessels). This may result in poor blood supply to the heart, causing angina. It also increases the chance that a blood vessel in your heart or brain will become completely blocked, causing a heart attack or stroke.

Nerve damage

High blood glucose levels can damage the tiny blood vessels of your nerves. This can lead to a tingling or burning pain that spreads from your fingers and toes up through your limbs. If the nerves in your digestive system are affected, you may experience nausea, vomiting, diarrhoea or constipation.

Retinopathy (damage to the retina at the back of the eye)

Blood vessels in the retina of your eye can become blocked, leaky or grow haphazardly. This prevents the light from fully passing through to your retina. If left untreated, it can damage your vision.

The better you control your blood sugar levels, the less chance you have of developing serious eye problems. Having an annual eye check either annually (every year) or at least every two years check by a specialist (an ophthalmologist or an optometrist) can help pick up signs of any potentially serious eye problems early on, so that they can be treated.

If it is caught early enough, diabetic retinopathy can be managed by aser treatment or eye injections. However, this will only preserve the sight you have and will not make it better.

Kidney disease

If the small blood vessels of your kidney become blocked and leaky, your kidneys will work less efficiently. In rare, severe cases this can lead to kidney failure and the need for a kidney transplant.

Foot problems

Damage to the nerves of the foot can mean that small nicks and cuts are not noticed, leading to the development of a foot ulcer. About 1 person in 20 with diabetes gets a foot ulcer, which can cause serious infection.

Check your feet every day and report any changes to your doctor, nurse or podiatrist. Look out for sores and cuts that do not heal, puffiness or swelling, and skin that feels hot to the touch. You should also have a foot examination at each diabetes clinic visit.

Sexual dysfunction

In men with diabetes (especially those who smoke), damage to the nerves and blood vessels can lead to erection problems. This may be treated with medication.

Women with diabetes may experience a reduced sex drive, reduced pleasure from sex, lack of vaginal lubrication, reduced ability to orgasm or painful sex. Women with a lack of vaginal lubrication or painful sex may find a vaginal lubricant or water-based gel helpful.

Miscarriage and stillbirth

Pregnant women with diabetes have an increased risk of miscarriage and stillbirth. If blood sugar levels are not carefully controlled in the early stages of pregnancy, there is an increased risk of the baby developing a serious birth defect.

Pregnant women with diabetes will usually have their antenatal check-ups in hospital or in a diabetic clinic, where healthcare professionals can keep a close eye on their blood sugar levels.

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Page last reviewed: 13/07/2011

The exact cause of type 2 diabetes is not fully understood, but many factors can increase your chance of developing it. For example, you may be at risk of developing type 2 diabetes if you:

  • are overweight or obese
  • do not get enough regular exercise

It may not be possible to avoid developing type 2 diabetes, but by controlling the risk factors you may be able to reduce your chances of getting it. For example, you should:

  • Lose weight, if you are overweight or obese.
  • Keep your waist size under 31.5 inches (80cm) if you are a woman, 35 inches (90cm) if you are an Asian man and 37 inches (94cm) if you are a man who is white or black.
  • Adults should do at least 150 minutes (2 hours and 30 minutes) of moderate-intensity aerobic activity (i.e. cycling or fast walking) every week.
  • Do not smoke.
  • Keep your blood pressure and cholesterol levels under control.
  • Only drink alcohol in moderation.

This advice can help anyone reduce their risk of developing type 2 diabetes, but is particularly important for those who have an increased risk of developing it.

Blood supplies oxygen to the body and removes carbon dioxide. It is pumped around the body by the heart.
Cholesterol is a fatty substance made by the body that is found in blood and tissue. It is used to make bile acid, hormones and vitamin D.

Recommended physical activity levels

  • Children aged under 5 years should do 180 minutes every day
  • Young people (5-18 years) should do 60 minutes every day
  • Adults (19-64 years) should do 150 minutes every week
  • Older adults (65+ years) should do 150 minutes every week

Page last reviewed: 13/07/2011

Look after your feet

Having diabetes means that you are more likely to develop problems with your feet, including foot ulcers and infections from minor cuts and grazes. This is because high blood glucose can damage the nerves in your feet.

To prevent problems with your feet, look at your feet every day and moisturise the soles of your feet daily. Wear shoes that fit properly and see a podiatrist or chiropodist (a specialist in foot care) regularly so that any problems are detected early.

Check your feet regularly for any cuts, blisters or grazes. You may not be able to feel them if there is damage to the nerves in your feet. See your GP if you have a minor injury to your foot that does not start to heal within a few days.

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Have regular eye tests

If you have type 2 diabetes, you should have your eyes tested annually (once a year) or at least once every two years to check for retinopathy.

Retinopathy is an eye condition where the small blood vessels in your eye become damaged. It can occur if your blood glucose level is too high for a long period of time (hyperglycaemia). If left untreated, retinopathy can eventually cause blindness.

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If you have diabetes and are thinking about having a baby, it's a good idea to discuss this with your diabetes healthcare team. Planning your pregnancy means you can ensure your blood sugar levels are as well controlled as they can be before you get pregnant.

You will need to keep your blood sugar under tight control, particularly before becoming pregnant and during the first eight weeks of your baby's development to reduce the risk of birth defects. You should also:

  • Check your medications. Tablets used to treat type 2 diabetes may harm your baby, so you may have to switch to insulin injections. 
  • Take a higher dose of folic acid tablets. Folic acid helps prevent your baby from developing spinal cord problems. Doctors now recommend that all women planning to have a baby take folic acid. Women with diabetes are advised to take 5mg each day (only available on prescription).
  • Have your eyes checked. Retinopathy, which affects the blood vessels in the eyes, is a risk for all people with diabetes. Pregnancy can place extra pressure on the small vessels in your eyes, so it's important to treat retinopathy before you become pregnant.

Your GP or diabetes healthcare team can give you further advice.

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Diabetes Federation Ireland

Get educated

You will be best equipped to manage your diabetes every day if you are given information and education when you are diagnosed and on an ongoing basis.

What is structured patient education?

Structured patient education means that there is a planned course that:

  • covers all aspects of diabetes
  • is flexible in content
  • is relevant to a person's clinical and psychological needs
  • is adaptable to a person's educational and cultural background

Ask your diabetes healthcare team about the available structured education programme.

Talk to others

Many people find it helpful to talk to others in a similar position and you may find support from a group for people with diabetes. Patient organisations have local groups where you can meet others who have been diagnosed with the condition.

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Page last reviewed: 13/07/2011

You can monitor your own blood glucose levels using a simple finger prick test.

Finger prick testing

What you will need:

  • blood testing strips
  • blood glucose meter
  • finger pricking device
  • lancets
  • blood glucose monitoring diary
  • sharps box for disposal of sharps

These are available from your GP or hospital.


  1. Before doing a finger prick test, make sure you have all your equipment in a clean, dry place.
  2. Wash your hands and rinse well with warm water (dirty hands can contaminate a blood sample and give an inaccurate result).
  3. Choose your finger and massage it to improve blood circulation.
  4. Pricking the fleshy part of your finger can hurt. Instead, prick the side of the finger away from the thumb. Squeeze your finger gently to obtain a drop of blood.
  5. Apply the drop of blood to the testing strip. The meter will automatically read the result. Note the result in your diary.

Page last reviewed: 13/07/2011

Clare Mehmet, a 58-year-old retired telecommunications interpreter, found out by chance that she had type 2 diabetes 10 years ago

"I was waiting for a train when I saw a poster saying, 'You could have diabetes: Are you thirsty all the time? Are you always tired? Is your vision blurred?' I was shocked because I'd been experiencing all the symptoms but put it to the back of my mind. So I promptly made an appointment with my GP, who confirmed that I had type 2 diabetes.

"At first I was terrified. I always thought people with diabetes were seriously ill, but once I looked into the condition I realised that as long as you change your diet and keep yourself fit and healthy, you can lead a full and active life.

"I've joined lots of support groups since I was diagnosed with diabetes and I do voluntary work to raise awareness about the condition. It's important that people watch out for the signs. Late diagnosis can cause serious complications, such as blindness, kidney failure, heart disease, stroke and nerve damage, which could lead to blood flow problems and even amputation. So if you have any worries, get tested."

Page last reviewed: 30/06/2014

Find out how the X-Pert Patient Education Programme can help you improve your lifestyle.

Content provided by NHS Choices www.nhs.uk and adapted for Ireland by the Health A-Z.

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