What is diabetes?

What happens in diabetes?

If you have diabetes, you have too much glucose in your blood. Glucose is a kind of sugar that your body uses for energy. But if it builds up in your blood it can make you ill. Doctors call this hyperglycaemia.

There are two main types of diabetes: type 1 and type 2. Type 1 diabetes usually starts suddenly, when you're a child or teenager. Type 2 diabetes comes on gradually, usually when you're 40 or over.

This information is for people with type 2 diabetes. About three-quarters of people with diabetes have type 2.

Ask your doctor: What type of diabetes do I have?

Glucose and your body

You always need to have some glucose in your blood. It comes from food and it gives your body energy.

Normally, a chemical called insulin helps keep the levels of glucose in your blood steady. Insulin is made in your body. But if you have type 2 diabetes, either your body is not making enough insulin, or the insulin your body makes is not working properly.

Doctors measure your glucose levels in millimoles per litre of blood (mmol/L for short). The amount of glucose in your blood should be between 4 mmol/L and 10 mmol/L. Your doctor may talk about your blood glucose level using just the number. For example, your doctor may say, "Your blood glucose is 10." But if you have diabetes, your blood glucose level may be as much as 30.

The level of glucose in your blood goes up and down throughout the day. It's higher when you've just eaten and lower first thing in the morning, or after you've been exercising.

Ask your doctor: What is my blood glucose level? What should it be ideally?

Who gets diabetes?

About 2 million people in the UK have diabetes. That's about 3 in 100. Some people are more likely to get it than others. These things make it more likely that you will get diabetes:

• Having a relative with type 2 diabetes
• Being very overweight (obese)
• Not exercising enough
• Coming from South Asian, African, African-Caribbean or Middle Eastern families (we don't know why this is)
• For women, getting diabetes during pregnancy
• Having high blood pressure or too much harmful fat in your blood.

Being overweight and not exercising enough are the main reasons why most people get diabetes. But not everyone who gets diabetes is overweight or doesn't exercise. Even some athletes get diabetes.

Ask your doctor: What's the most likely reason for my diabetes?

What are the symptoms of diabetes?

Not everyone with type 2 diabetes gets symptoms. But these are some of the more common symptoms:

• Needing to pass urine more often: Your body tries to get rid of the extra glucose in your blood by flushing it out in your urine.
• Feeling very thirsty: You may feel thirsty more often. This is partly because you pass urine more.
• Feeling very hungry or tired: If you have diabetes, your body can't use the glucose in your blood properly. So your cells don't get the energy they need. This makes you hungry and tired.
• Losing weight without trying: Your cells can't use the glucose in your blood, so they start to burn up fat instead.

These symptoms should go away if your treatment is working properly. But if it's not diagnosed and treated properly, type 2 diabetes gets worse. You might get:

• Blurred vision
• An infection called candidiasis. You might know this as thrush. You might get it in your mouth or in the folds of your skin. If you're a woman you might get it in your vagina.
• Wounds or sores that don't heal well.

There are some symptoms you need to watch out for, because they mean your blood glucose may have got very high. These include feeling light-headed, dizzy, sick or confused, or losing consciousness. If you get these symptoms, you need medical help straight away.

Ask your doctor: What symptoms should I look out for that might mean my diabetes is getting worse?

How do doctors diagnose diabetes?

Your doctor will need to give you a blood test to find out how much glucose is in your blood. The usual test for diabetes measures glucose levels first thing in the morning, before you eat. The result is called your fasting plasma glucose level. If is more than 7, you have diabetes.

This may be the only test you need. But if your glucose level is close to 7 you may need a second test to be sure. The second test is called an oral glucose tolerance test. This is the most reliable test for diagnosing diabetes. It shows how your body copes with a lot of glucose.

You take this test first thing in the morning, before you eat. First, your doctor measures your glucose level. Then you drink a very sugary liquid. Two hours later, the level of glucose in your blood is measured again. If it's 11.1 or more, you have diabetes.

If you've been told you have diabetes, your doctor will probably want to do other tests on your blood and urine. These tests are to find out how well your thyroid gland, liver and kidneys are working. You will also have a test to see if your cholesterol is high. After you've been diagnosed with diabetes, you should have a thorough check-up at least once a year with a doctor experienced in treating diabetes.

Ask your doctor: What tests do I need?

What will happen to me?

If you have diabetes, you should be able to lead a normal life. You may need to:

• Take medicines regularly
• Watch what you eat
• Exercise regularly
• Check your blood glucose level throughout the day.

Apart from these changes, you should be able to take part in all your normal activities. You may need to tell the Driver and Vehicle Licensing Agency (DVLA) about your diabetes, if you have a health problem that could affect your driving. Check with your doctor.

When you've had diabetes for a long time, you may have a higher chance of a heart attack, a stroke or problems with your circulation. You may also get problems with your eyes, kidneys and feet. These problems are called complications. Not everyone with diabetes gets complications. Some people have diabetes for 40 or 50 years without getting complications. If you carefully control your blood glucose level, you are more likely to stay healthy. Having regular health checks with your doctor can help you to avoid these problems.

Ask your doctor: Do I have any complications from my diabetes? If not, how can I best avoid getting problems in future?

For more information about what you can do to help yourself, read "Diabetes: what can I do to keep myself healthy?"