What is pre-diabetes?

People with pre-diabetes have blood glucose levels that are higher than normal but not high enough for a diagnosis of diabetes. This condition raises the risk of developing type 2 diabetes, heart disease, and stroke.

Pre-diabetes is also called impaired fasting glucose (IFG) or impaired glucose tolerance (IGT), depending on the test used to diagnose it. Some people have both IFG and IGT.

• IFG is a condition in which the blood glucose level is high (100 to 125 mg/dL) after an overnight fast, but is not high enough to be classified as diabetes. (The former definition of IFG was 110 mg/dL to 125 mg/dL.)
  
  
• IGT is a condition in which the blood glucose level is high (140 to 199 mg/dL) after a 2-hour oral glucose tolerance test, but is not high enough to be classified as diabetes.

Pre-diabetes is becoming more common in the United States, according to new estimates provided by the U.S. Department of Health and Human Services. About 40 percent of U.S. adults ages 40 to 74&mdashor 41 million people&mdashhad pre-diabetes in 2000. New data suggest that at least 54 million U.S. adults had pre-diabetes in 2002. Many people with pre-diabetes go on to develop type 2 diabetes within 10 years.

The good news is that if you have pre-diabetes, you can do a lot to prevent or delay diabetes. Studies have clearly shown that you can lower your risk of developing diabetes by losing 5 to 7 percent of your body weight through diet and increased physical activity. A major study of more than 3,000 people with IGT, a form of pre-diabetes, found that diet and exercise resulting in a 5 to 7 percent weight loss&mdashabout 10 to 14 pounds in a person who weighs 200 pounds&mdashlowered the incidence of type 2 diabetes by nearly 60 percent. Study participants lost weight by cutting fat and calories in their diet and by exercising (most chose walking) at least 30 minutes a day, 5 days a week.