Diabetes, type 2 - What is it?
In this section
If you have diabetes, you have too much glucose in your blood. Glucose is a kind of sugar that your body uses for energy. If it builds up in your blood, it can make you ill.
Diabetes doesn't go away. And if you don't treat it, you can get serious health problems. If you change the way you live, take medicines and keep a close watch on your condition, you can keep your glucose levels under control. You should be able to live a long and healthy life.
Key points for people with diabetes
- Diabetes is a serious condition. But with the right treatment you should be able to stay healthy.
- If you have diabetes you have too much glucose in your blood.
- There are two main types of diabetes: type 1 and type 2. This information is for people with type 2 diabetes. See also Type 1 diabetes.
- Many people with diabetes don't know they have it. You may not have any symptoms, or you may think the symptoms you do have aren't important. If you have symptoms such as feeling very thirsty, hungry or tired, having blurry vision or needing to urinate a lot, don't ignore them.
- Over time, having too much glucose in your blood can damage your blood vessels. This can lead to problems in your heart, eyes, kidneys and other parts of your body.
- If you keep your blood glucose level as close to normal as possible you may be able to avoid some of these health problems.
- It's not easy to keep your blood glucose under control. And if you don't feel ill, you may not want to think about your glucose level. But keeping it under control is an important part of staying healthy.
What's a normal glucose level?
You always need to have some glucose in your blood. It comes from food and it gives your body energy. Every cell in your body needs glucose to work properly.
Normally, the amount of glucose in your blood is carefully controlled by a chemical called insulin. Insulin is a hormone made by your pancreas, a gland that sits behind your stomach. Insulin helps move glucose from your blood into your body's cells. Your cells use the glucose as energy. Insulin keeps your blood levels of glucose steady.
Doctors measure your glucose levels in millimoles. The amount of glucose in your blood should be between 4 millimoles per litre of blood (mmol/L for short) and 10 mmol/L.[1]
Your doctor may talk about your blood glucose level using just the number. For example, your doctor may say, "Your blood glucose is 10." Normally, your blood glucose level goes up and down throughout the day. Before you eat breakfast, for example, it should be between 4 mmol/L and 7 mmol/L. An hour or two after you eat, it may rise to 10 mmol/L.
To learn more, see What is glucose? and How does my body control my blood glucose level?
Types of diabetes
There are two main types of diabetes: type 1 and type 2.
- Type 1 diabetes usually starts in adolescence.
- Type 2 comes on gradually, usually when you're 40 or over.
- There's also a condition called impaired glucose tolerance. This isn't diabetes, but it does increase your chances of getting diabetes.
- Some women get a kind of diabetes while they're pregnant. This is called gestational diabetes.
This information is for people with type 2 diabetes. For more information about other types of diabetes, see:
Type 2 diabetes
Most people who have diabetes get type 2 diabetes. More than three-quarters of people with diabetes have this type.[2]
Type 2 diabetes usually starts later in life and is more common in people who are very overweight (obese). But it's getting commoner in children. This is because more children are overweight today than in the past.
Type 2 diabetes used to be called non-insulin-dependent diabetes mellitus (or NIDDM for short) because people who have type 2 diabetes often don't need to take insulin. It's sometimes called adult-onset diabetes because it tends to start in people over 40 years old.
What happens in type 2 diabetes?
If you have diabetes, your body can't control how much glucose is in your blood. Instead of the glucose being gradually used up as fuel by your cells, it builds up in your bloodstream. You'll hear the word hyperglycaemia a lot. It means having too much glucose in your blood. See What are the symptoms of type 2 diabetes? to find out how this affects you.
You need insulin to keep your glucose level under control. In diabetes, your glucose level can get too high for different reasons.
- Your body may not be making enough insulin. It might make only a little or none at all.
- Your body may be making insulin but the insulin isn't working properly. Scientists think that your cells don't behave as they should when insulin reaches them. Doctors call this insulin resistance.
- One of insulin's jobs is to tell cells in your liver how to use glucose. If there's any extra glucose in your blood, it should be stored in your liver. But if you have type 2 diabetes, your liver cells don't get the right messages. So instead of storing the glucose, your liver pumps more glucose into your blood.
If you have diabetes, a blood test taken first thing in the morning before you have eaten will show a glucose level of more than 7 mmol/L. But it can be much higher, rising to as much as 30 mmol/L or more.
Why me?
Certain things can increase your chances of getting a disease. Doctors call these things risk factors. Having a risk factor for diabetes doesn't mean you will get the disease for sure. It just means you are more likely to get diabetes than someone who doesn't have that risk factor.
Some risk factors for type 2 diabetes are:
- Having a relative with type 2 diabetes: You're more likely to get type 2 diabetes if someone in your family has it. Your genes play a role. If both of your parents have type 2 diabetes, you have a 1 in 2 chance of getting it.[3] (To find out more about what these numbers mean, see Understanding risks.)
- Being obese: Some people believe that eating too much sugar causes diabetes. They think this extra sugar wears out your pancreas. This isn't true. What is important is your actual weight.[2] Obesity is the main risk factor for type 2 diabetes.
- Lack of exercise: About 80 percent of people with type 2 diabetes are overweight and don't take enough exercise. If you're at risk of getting type 2 diabetes, you can reduce your risk if you exercise. For example, if you're overweight and you lose about 5 percent of your body weight, and you also take regular, moderate exercise (such as a brisk walk for 30 minutes, five days a week), your chance of getting diabetes is reduced by one-half.[4]
- Your ethnic origin: People of South Asian, African, African-Caribbean and Middle Eastern descent are more likely to get type 2 diabetes than other people in the UK.[2] We're not certain why this is.
- Factors related to pregnancy: If you are a woman, you are more likely to get type 2 diabetes if you give birth to a baby weighing more than 4 kilograms (9 pounds) or have diabetes during pregnancy.[5] For more, see Other types of diabetes and high blood glucose.
- Having a condition called the metabolic syndrome: People who have this condition are more likely to get type 2 diabetes. To read more, see The metabolic syndrome.
References
- Diabetes UK. Guide to diabetes: treatments and your health: monitoring your health Available at http://www.diabetes.org.uk/Guide-to-diabetes (accessed on 13 November 2006).
- Diabetes UK. Guide to diabetes, Introduction to diabetes, What is diabetes. Available at http://www.diabetes.org.uk/Guide-to-diabetes (accessed on 13 November 2006).
- American Diabetes Association. The genetics of diabetes. Available at http://www.diabetes.org/genetics.jsp (accessed on 31 August 2006).
- Knowler WC, Barrett-Connor E, Fowler SE, et al. Reduction in the incidence of type 2 diabetes with lifestyle intervention or metformin. New England Journal of Medicine. 2002; 346: 393-403.
- Harris MI. Gestational diabetes may represent discovery of preexisting glucose intolerance. Diabetes Care. 1988; 11: 402-411.
Glossary
- kidney
- Your kidneys are organs that filter your blood to make urine. You have two kidneys, on either side of your body. They are underneath your ribcage, near your back.
- hormones
- Hormones are chemicals that are made in certain parts of the body. They travel through the bloodstream and have an effect on other parts of the body. For example, the female sex hormone is made in a woman's ovaries. Oestrogen has many different effects on a woman's body. For example, it makes the breasts grow at puberty and helps control periods. It is also needed to get pregnant.
- gland
- A gland is any group of cells in the body that makes and releases something for use by another part of the body. For example, the thyroid gland makes a hormone called thyroxine. This acts on receptors within cells. By acting on the receptors it gives the cells a message to speed up their metabolism and work harder.
- obesity
- If your body stores more energy than you need, this can make you overweight. The excess energy is stored in your fat cells. If your weight goes above a certain level, doctors call this obesity. Obesity is considered a medical condition. The excess weight can be a strain on your bones and joints. And if you are obese, you're more likely to get other diseases. Doctors have developed a scale for telling how much excess weight you have. This measure, called the body mass index (BMI), depends on your height.
- liver
- Your liver is on the right side of your body, just below your ribcage. Your liver does several things in your body, including processing and storing nutrients from food, and breaking down chemicals, such as alcohol.
- genes
- Your genes are the parts of your cells that contain instructions for how your body works. Genes are found on chromosomes, structures that sit in the nucleus at the middle of each of your cells. You have 23 pairs of chromosomes in your normal cells, each of which has thousands of genes. You get one set of chromosomes, and all of the genes that are on them, from each of your parents.
- pancreas
- Your pancreas is an organ that's behind your stomach. It makes several different chemicals. Some of the chemicals help your body digest food. Your pancreas also makes a chemical called insulin, which helps your body use the sugar in your blood.
© BMJ Publishing Group Limited ("BMJ Group") 2007. All rights reserved
This information does not replace medical advice. If you are concerned you might have a medical problem please ask your Boots pharmacy team in your local Boots store, or see your doctor.
