Impaired fasting glycaemia is when blood glucose levels in your body are raised during periods without food (fasting), but aren’t high enough to mean that you have diabetes.
Impaired fasting glycaemia is sometimes called pre-diabetes and is also known as impaired fasting glucose. It’s estimated that around seven million people in the UK have impaired fasting glycaemia.
If you have impaired fasting glycaemia, your body isn't able to regulate glucose as efficiently as it should. Glucose is a major source of energy for most cells in your body, including your brain. Carbohydrate foods, such as bread, pasta and rice, are broken down and turned into glucose when you eat them. Your liver can also produce glucose.
One function of your blood is to carry glucose around your body. When glucose reaches body tissues, such as muscle cells, it's absorbed and converted into energy. The amount of glucose in your blood is automatically regulated by a hormone called insulin that is produced by your pancreas. If your pancreas doesn’t produce enough insulin or any at all, or the insulin that is produced doesn’t work properly (insulin resistance), the amount of glucose in your blood can become too high.
Blood glucose levels can be measured in a laboratory by testing a blood sample. This is usually done when you haven’t eaten for eight hours and is called a fasting blood glucose test. The amount of glucose in your blood changes throughout the day depending on what you're eating and drinking.
Impaired fasting glycaemia has no symptoms and can often go undiagnosed for years. Although there are no symptoms, many people diagnosed with impaired fasting glycaemia are overweight. Nine out of 10 people with impaired fasting glycaemia have high blood pressure, raised cholesterol levels or a family history of the condition.
Having impaired fasting glycaemia increases your risk of developing type 2 diabetes. Many people with type 2 diabetes have no symptoms, but if you do have symptoms, they might include:
These symptoms may be caused by problems other than type 2 diabetes. If you have any of these symptoms see your GP for advice.
If you have impaired fasting glycaemia, you’re at greater risk of developing type 2 diabetes and heart disease.
Impaired fasting glycaemia develops if your body becomes unable to control your glucose levels. Your body may not produce enough insulin or be able to use the insulin that it does produce properly. There are a number of factors that make you more likely to develop impaired fasting glycaemia. You may be at risk of getting impaired fasting glycaemia if you're black or South Asian and over 25, or if you're Caucasian and over 40, and if:
Impaired fasting glycaemia is diagnosed by testing glucose levels in your blood. The first test you will have is called a fasting plasma glucose test. You will be asked not to eat anything for eight to 10 hours before a blood sample is taken.
Depending on the results of this test your GP may ask you to have a two-hour plasma glucose test (also known as an oral glucose tolerance test, or OGTT). If you have this test, your GP will ask you not to eat anything for 12 hours before the blood sample is taken. After the blood sample is taken, your GP will ask you to swallow a drink containing 75g of glucose. Another blood test is then taken two hours after the first to see how your body has dealt with the glucose you swallowed.
Impaired fasting glycaemia doesn't need medical treatment, but it's important to try and lower your blood glucose levels by making changes to your lifestyle. This can help to prevent or delay the development of type 2 diabetes.
If you have had an impaired fasting glycaemia level once, you should have regular fasting glucose tests every year.
People with impaired fasting glycaemia have a greater risk of developing type 2 diabetes and are at an increased risk of heart disease and stroke, therefore it's important to do what you can to reduce your chances of developing these conditions. You should aim to reach and maintain normal or near-normal blood glucose levels. The following are examples of how you can do this.
As well as taking the steps above you can also reduce your risk of heart disease and stroke by giving up smoking.
Produced by Dylan Merkett, Bupa Health Information Team, May 2012.
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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