The epidemic of type 2 diabetes is alarming-and more dangerous than many people ever imagine. The disease, which affects 20 million Americans, increases the risk for heart attack and stroke. Complications from the disease include blindness, kidney failure, impotence and poor wound healing that can lead to amputation.

Until recently, doctors diagnosed diabetes only when a patient had full-blown symptoms, which typically develop gradually over a period of years.

Now: You can stop diabetes in its tracks if you recognize and take action against "prediabetes," which affects more than 40 million people between the ages of 40 and 74. Here's how...

When Sugar Isn't Sweet

Glucose, a simple sugar molecule that is metabolized from the food you eat, is basic fuel for your body. It is broken down in cells to produce energy that powers your muscles, lets you think and keeps your heart pumping and your lungs breathing.

The hormone insulin, which is produced by your pancreas, plays a key role in this process, escorting glucose from the bloodstream into the cells. \7hen there isn't enough insulin to do the job or the insulin is not effective, sugar builds up in the blood. That's when the trouble begins.

To diagnose diabetes, doctors order blood tests that measure the amount of glucose in your bloodstream. One test, fasting plasma glucose (FPG), checks the glucose level first thing in the morning, before you have eaten anything. A normal glucose level is less than 100 milligrams per deciliter (mg/dL).

The oral glucose tolerance test(OGTT) is a bit more complicated-after fasting all night, you drink a sugary liquid, and your glucose level is tested two hours later. A normal result is less than140 mg/dL.

If your FPG is 726 mg/dL or higher. ..or the two-hour OGTT is higher than 200 mg/dl, you likely have diabetes. Your pancreas no longer secretes enough insulin for proper glucose metabolism or your body has become more resistant to its effects. This means that your risk of developing complications, such as heart disease, kidney failure or vision loss, has more than doubled.

An Earlier Diagnosis

There is also an intermediate condition-between normal and diabetes. Fasting blood sugar of 100 to 125 mg/dL is called impaired fasting glucose. If the two-hour OGTT is between 140 and 2OO mg/dL, it is known as impaired glucose tolerance.

Today, these conditions are called prediabetes, meaning your insulin activity has already started to fall short of the amount your body needs. And if something isn't done, there's a good chance you'll go on to develop full-blown diabetes.

What are the odds? Fasting blood sugar between 100 and 110 mg/dl means you have a 20% chance of developing diabetes within five to 10 years. if it's higher than 110, you have a 4O% chance of getting diabetes. If both the fasting blood sugar and two-hour glucose tolerance tests are elevated, the odds increase even more.

At the prediabetes level, excess blood sugar has already started to take its toll. For example, the risk of heart disease is 1.5 times higher for a prediabetic than for someone who has normal blood sugar.

Do You Have Prediabetes?

To determine whether you have prediabetes, ask your doctor for a fasting glucose test-especially if you are at increased risk due to...

Excess bodyweight.

Family history of diabetes (parent, brother or sister).

Diabetes during pregnancy (gestational diabetes).

Asian, African-American or Hispanic ethnicity.

If any of these risk factors applies to you, have your blood sugar checked at your next physical. After age 45, you should have it checked at least every three years. Given the high rates of diabetes today, everyone older than 45 should consider getting tested.

Treatment For Prediabetes

Slightly elevated blood sugar doesn't mean you're destined to get diabetes. Fairly moderate lifestyle changes can reduce that risk by more than 50%.

Obesity increases diabetes risk. If you are overweight, bring your weight down by 5% to l0%. Ideally, your weight should be brought down to the normal range, which means a body mass index (BMI), a ratio of weight to height, of 18.5 to 24.9. To find your BMI, use the free calculator at the National Heart, Lung and Blood Institute website at http://nhlbisupport.com/bmi. Or use the formula (weight in pounds x 703) / height in inches squared.

Important finding: A Finnish study of 522 middle-aged, overweight people who had prediabetes found that diabetes risk was reduced by 58% among those who participated in diet and exercise programs for three years compared with those in a control group, who experienced no reduction.

How to stop prediabetes...

Diet wisely. Consuming fewer calories than you burn is the key to weight loss. Some research also suggests that reducing saturated fat (most beef and some dairy products), and the resulting weight loss that can occur, helps reverse prediabetes, allowing your body to use insulin more efficiently. A diet that is rich in complex carbohydrates, such as fruits, vegetables and whole grains, will meet these goals-and is best for everyone's general health. Consuming fewer calories than you burn is the key to weight loss. Some research also suggests that reducing saturated fat (most beef and some dairy products), and the resulting weight loss that can occur, helps reverse prediabetes, allowing your body to use insulin more efficiently. A diet that is rich in complex carbohydrates, such as fruits, vegetables and whole grains, will meet these goals-and is best for everyone's general health.

Exercise regularly. physical activity helps control your weight and improves your body's ability to use insulin. Aim for at least 30 minutes of exercise five or more days a week. The type of exercise doesn't seem to matter, as long as it requires modest exertion-brisk walking, swimming, riding a bike, etc.

Forgo medication. Blood sugar in people who have prediabetes can be reduced using prescription diabetes medication such a s metformin (Glucophage). However, research suggests that this drug is not as effective as diet and exercise in preventing diabetes.

Important finding: In a New England Journal of Medicine study, 3,234 men and women who had prediabetes were randomly assigned to a lifestyle program or to the drug metformin.

After three years, weight loss and exercise reduced diabetes incidence by 58%, while drug treatment reduced diabetes incidence by only 31%.

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