Prediabetes

What is prediabetes?
What does prediabetes have to do with my heart?
What are my risk factors for prediabetes?
How do I know if I have prediabetes?
What can I do to prevent prediabetes?

What is prediabetes?
It's a condition that occurs when the blood glucose (blood sugar) levels are higher than normal but not high enough to be diagnosed as diabetes. lt's also called impaired fasting glucose (IFG) or impaired glucose tolerance (IGT). People with IFG and IGT are at increased risk for developing type 2 diabetes, heart disease and stroke. The American Heart Association estimates that 59.7 million Americans 20 years and older have prediabetes.

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What does prediabetes have to do with my heart?
Prediabetes can affect the heart in several ways. In fact, long-term damage to the cardiovascular system may occur while a person has prediabetes. A recent study indicates that prediabetes more than doubles the risk of death due to heart attack.*

Family history. If you have a blood relative with diabetes, your risk for developing it is significantly increased. Map out your family history tree and take it to your doctor to find out what it means for you.
Race or ethnic background. People of African, Asian, Hispanic and Native American descent have a greater risk of diabetes.
Being overweight. If you're 20 percent or more over your optimal body weight, you have a higher risk of developing diabetes.
Hypertension. High blood pressure increases your risk for diabetes.
Age. The older you are, the higher your risk.
Alcohol use. Heavy alcohol consumption over time increases your risk.
Smoking. A person who smokes 16 to 25 cigarettes a day is three times more likely to develop diabetes than a nonsmoker.
History of gestational diabetes. Developing diabetes during pregnancy or delivering a baby over 9 lbs. can increase your risk.

How do I know if I have prediabetes?
Prediabetes has no symptoms, so you can have it and not know it. It can only be diagnosed by your healthcare provider using two different tests:

Fasting Plasma Glucose Test (FPG) — This test must be done on an empty stomach. So for eight hours before the test, the person must fast (nothing to eat or drink, except water). A person's plasma is combined with other substances, then from the resulting reaction, the amount of glucose in the plasma is determined.
- A person with prediabetes has a fasting blood glucose level from 100 to 125 mg/dL.
Oral Glucose Tolerance Test (OGTT) — This test is done to see how well the body handles a standard amount of glucose. It measures the amount of glucose in a person's plasma before and two hours after drinking a large premeasured beverage containing glucose. A doctor can then compare the before and after glucose levels to see how well the body processed the sugar.
- A person with prediabetes will have a blood glucose level between 140 and 199 mg/dL two hours after the premeasured drink

The U.S. Department of Health and Human Services recommends that everyone who is overweight and older than 45 be tested for prediabetes. However, if you're younger than 45, overweight and have one or more other risk factors, such as high blood pressure or high cholesterol, or are in one of the high-risk groups listed above, testing is still appropriate. If your blood glucose levels are in normal range, then testing should be done about every three years. If you have prediabetes, you should be checked for diabetes every one to two years after diagnosis.

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What can I do to prevent prediabetes?
Physical inactivity and overweight/obesity are the most important modifiable risk factors for prediabetes. Being physically active for at least 30 minutes a day and losing 5 percent to 7 percent of your body weight (about 10 pounds for a 200-lb. person) can lower your risk by half. And your risk continues to decrease as you lose even more weight. Increasing physical activity and eating a heart-healthy diet can also help you lose weight and lower your risk of diabetes and heart and circulatory illnesses.

Talk to your doctor about how to change your eating and physical activity habits to reduce your chances of developing diabetes.

* Circulation, July 10 2007; doi:10.1161/CIRCULATIONAHA.106.685628

This content is reviewed regularly. Last updated 09/05/08.