Type 2 diabetes
The most common form of diabetes is
type II diabetes (type 2). About
90 to 95 percent of people with diabetes have type
2. The rate of type 2 diabetes diagnosis, both in children and adults, is
increasing in the United States at an extremely alarming
rate (referred to by some as almost an "epidemic").
This form of diabetes is most often associated with older age,
obesity, family history of diabetes, previous
history of gestational diabetes,
physical inactivity, and certain ethnicities. About 80
percent of people with type 2 diabetes are overweight. Type 2 diabetes is increasingly being
diagnosed in children and adolescents.
When type II diabetes is diagnosed, the pancreas is usually producing enough insulin, but for unknown reasons the body cannot use insulin effectively, a condition called insulin resistance. After several years, insulin production decreases. The result is the same as for type 1 diabetes: glucose builds up in the blood and the body cannot make efficient use of its main source of fuel.
The symptoms of type 2 diabetes develop gradually. Their onset is not as sudden as in type 1 diabetes. Symptoms may include fatigue, frequent urination, increased thirst and hunger, weight loss, blurred vision, and slow healing of wounds or sores. Some people have no symptoms.
How is type 2 diabetes diagnosed?
The fasting blood glucose test is the preferred test for diagnosing diabetes in children and non-pregnant adults. It is most reliable when done in the morning. However, a diagnosis of diabetes can be made based on any of the following test results, confirmed by retesting on a different day:
- A blood glucose level of 126 milligrams per deciliter (mg/dL) or more after an eight-hour fast. This test is called the fasting blood glucose test.
- A blood glucose level of 200 mg/dL or more two hours after drinking a beverage containing 75 grams of glucose dissolved in water. This test is called the oral glucose tolerance test (OGTT).
- A random (taken at any time of day) blood glucose level of 200 mg/dL or more, along with the presence of diabetes symptoms.
Gestational diabetes is diagnosed based on blood glucose levels measured during the OGTT. Glucose levels are normally lower during pregnancy, so the cutoff levels for diagnosis of diabetes in pregnancy are lower. Blood glucose levels are measured before a woman drinks a beverage containing glucose. Then levels are checked one, two, and three hours afterward. If a woman has two blood glucose levels meeting or exceeding any of the following numbers, she has gestational diabetes: a fasting blood glucose level of 95 mg/dL, a one-hour level of 180 mg/dL, a two-hour level of 155 mg/dL, or a three-hour level of 140 mg/dL.
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 two-hour oral glucose tolerance test, but is not high enough to be classified as diabetes.
- Pre-diabetes is far more common in the United States than previously believed, 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—or 41 million people—currently have the condition. 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 a form of pre-diabetes found that doing so lowered 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, five days a week.
Gestational diabetes
Some women develop gestational diabetes late in pregnancy. Although this form of diabetes usually disappears after the birth of the baby, women who have had gestational diabetes have a 20 to 50 percent chance of developing type 2 diabetes within 5 to 10 years. Maintaining a reasonable body weight and being physically active may help prevent development of type 2 diabetes.
About 3 to 8 percent of pregnant women in the United States develop gestational diabetes. As with type 2 diabetes, gestational diabetes occurs more often in some ethnic groups and among women with a family history of diabetes. Gestational diabetes is caused by the hormones of pregnancy or a shortage of insulin. Women with gestational diabetes may not experience any symptoms.
