Prediabetes is a term used when a person's blood sugar (glucose) level is above normal but below a level that indicates diabetes. Prediabetes has no symptoms. It can only be diagnosed with a blood glucose test.

Prediabetes may be called impaired glucose tolerance or impaired fasting glucose, depending on the test used to diagnose it.

People who are overweight or physically inactive are at risk for prediabetes. Other things that increase risk include:

• Family history of diabetes.
• High cholesterol.
• African-American, Asian-American, Hispanic, Native American, or Pacific Islander ethnicity.
• History of gestational diabetes. This is a type of diabetes that develops during pregnancy. Delivering a baby that weighed more than 9 pounds is also a risk.
• Polycystic Ovary Syndrome (PCOS), a hormone imbalance that interferes with normal ovulation.
• Metabolic syndrome, a cluster of conditions related to the body's metabolism. These conditions include excess body fat (particularly abdominal obesity); elevated triglycerides, blood pressure, and blood sugar; and low HDL cholesterol (the "good" cholesterol).

Some people with prediabetes go on to develop type 2 diabetes later in life. And recent studies show that prediabetes increases the risk of heart disease. People with prediabetes may be able to prevent type 2 diabetes by losing weight, eating a healthy diet, and exercising regularly.