Diabetes is a disease in which the body does not produce or properly use insulin. Insulin is a hormone that is needed to convert sugar, starches and other food into energy needed for daily life. The cause of diabetes continues to be a mystery, although both genetics and environmental factors such as obesity and lack of exercise appear to play roles.

There are 20.8 million children and adults in the United States, or 7% of the population, who have diabetes. While an estimated 14.6 million have been diagnosed with diabetes, unfortunately, 6.2 million people (or nearly one-third) are unaware that they have the disease.

In order to determine whether or not a patient has pre-diabetes or diabetes, health care providers conduct a Fasting Plasma Glucose Test (FPG) or an Oral Glucose Tolerance Test (OGTT). Either test can be used to diagnose pre-diabetes or diabetes. The American Diabetes Association recommends the FPG because it is easier, faster, and less expensive to perform.

With the FPG test, a fasting blood glucose level between 100 and 125 mg/dl signals pre-diabetes. A person with a fasting blood glucose level of 126 mg/dl or higher has diabetes.

In the OGTT test, a person's blood glucose level is measured after a fast and two hours after drinking a glucose-rich beverage. If the two-hour blood glucose level is between 140 and 199 mg/dl, the person tested has pre-diabetes. If the two-hour blood glucose level is at 200 mg/dl or higher, the person tested has diabetes.

Major Types of Diabetes

Type 1 diabetes
Results from the body's failure to produce insulin, the hormone that "unlocks" the cells of the body, allowing glucose to enter and fuel them. It is estimated that 5-10% of Americans who are diagnosed with diabetes have type 1 diabetes.

Type 2 diabetes
Results from insulin resistance (a condition in which the body fails to properly use insulin), combined with relative insulin deficiency. Most Americans who are diagnosed with diabetes have type 2 diabetes.

Gestational diabetes
Gestational diabetes affects about 4% of all pregnant women - about 135,000 cases in the United States each year.

Pre-diabetes
Pre-diabetes is a condition that occurs when a person's blood glucose levels are higher than normal but not high enough for a diagnosis of type 2 diabetes. There are 54 million Americans who have pre-diabetes, in addition to the 20.8 million with diabetes.

Additional Information

Recently Diagnosed
You or someone you love has just been diagnosed with diabetes -- chances are you have a million questions running through your head. This area of our Web site can help ease your fears and teach you more about living with diabetes or caring for someone with diabetes, and connect you with others affected by diabetes who will listen and share their own experiences.

Diabetes Symptoms
Often diabetes goes undiagnosed because many of its symptoms seem so harmless. Learn what they are in this section.

Diabetes Risk Test
More than 20 million Americans have diabetes -- nearly one in three does not know it! Take our diabetes risk test to see if you are at risk for having diabetes. Diabetes is more common in African Americans, Latinos, Native Americans, Asian Americans and Pacific Islanders.

The Genetics of Diabetes
You've probably wondered how you got diabetes. You may worry that your children will get it too. Unlike some traits, diabetes does not seem to be inherited in a simple pattern. Yet clearly, some people are born more likely to get diabetes than others.