New guidelines from the American Diabetes Association (ADA) and NIH recommend that most middle-aged people be tested for "pre-diabetes" to determine their risk for developing diabetes. The term "pre-diabetes" is now used to describe levels of blood glucose that are higher than normal but not high enough to be considered diabetes. This condition used to be called "impaired glucose tolerance."

An estimated 16 million Americans over the age of 40 have pre-diabetes, and most will advance to diabetes within ten years. Research has shown that some long-term damage to the body may already be occurring in such individuals, before diabetes is diagnosed.

The process can be slowed or stopped, however. Recent results from the Diabetes Prevention Program showed that pre-diabetic overweight individuals who lose just five to ten percent of their weight and undertake a modest physical activity program, such as walking for 30 minutes five times a week, can prevent or delay the development of diabetes. Some who do this can return their elevated blood glucose levels to the normal range.

The new guidelines recommend:

• Everyone aged 45 or older should be tested, especially anyone who is overweight.
• Younger adults should be tested if they are significantly overweight and have another risk such as a relative with diabetes, high cholesterol or high blood pressure, had gestational diabetes, or belong to a racial minority group.
• If the test is normal, it should be repeated every three years.
• If the test identifies pre-diabetes, then a program of weight loss and exercise should be undertaken.

Doctors test for pre-diabetes using either a fasting plasma glucose test, in which blood levels of glucose are measured in the morning before eating or the oral glucose tolerance test, in which the blood is tested after fasting and again two hours after drinking a glucose-rich drink.

Related information Diabetes diagnosis

Sources:

• ADA, NIH/NIDDK. Position statement: the prevention or delay of type 2 diabetes. Diabetes Care, April 2002;25:742-749.
• ADA. Pre-diabetes. www.diabetes.org