WASHINGTON (AP) - Nearly 16 million Americans have a type of high blood sugar the government is now calling ``pre-diabetes,'' and new guidelines urge most middle-aged people to get tested so they can take steps to prevent full-blown diabetes.

``Diabetes is a battle that we can all win,'' Health and Human Services Secretary Tommy Thompson said Wednesday. ``It doesn't have to be devastating. It can be prevented and, if it occurs, managed successfully.''

Some 17 million Americans have diabetes, 8 percent more than previously estimated, the government announced. The updated figure reflects new census data.

Some people are born with diabetes. But the vast majority have Type 2 diabetes, an illness that develops, often in middle age, when their bodies lose the ability to turn blood sugar into energy.

It is a leading cause of blindness, kidney failure, amputations and heart disease, and kills 180,000 Americans each year. Proper therapy can ease those complications, yet experts say one-third of diabetics do not know the disease is silently festering in their bodies.

``Most people with pre-diabetes don't know they have it,'' said Judith Fradkin of the National Institutes of Health. ``The important thing is to find it so you can treat it.''

Diet and exercise can at least delay, if not completely prevent, Type 2 diabetes from striking. The question is how to identify and help people at high risk; diabetes screening is not routine.

``People with pre-diabetes need to be identified and they need to know the seriousness of their condition,'' Thompson said.

Doctors have long known that a condition called ``impaired glucose tolerance'' was an indication of such risk. Testing shows the sugar in their blood gradually rising.

The government released data estimating that 16 million Americans over age 40 have impaired glucose tolerance - and renamed the condition ``pre-diabetes'' to make it easier for people to understand.

New guidelines recommend that millions of middle-aged people get tested during their next regular doctor visit to see if they have either pre-diabetes or the full disease.

According to the guidelines, from the American Diabetes Association and the NIH:

-Everyone 45 or older should consider getting tested. Testing is strongly recommended if those people are overweight.

-Doctors should consider testing younger adults if they are significantly overweight and have another risk - a diabetic relative; bad cholesterol; high blood pressure; diabetes during pregnancy or gave birth to a baby bigger than 9 pounds; or belong to a racial minority group.

-If the test is normal, repeat it every three years.

If the test finds someone has pre-diabetes, a major study last year found that walking 30 minutes a day and dropping about 15 pounds can cut in half the risk of getting the disease.

``We're talking about significant benefits that can be derived from modest exercise,'' Thompson said. ``You don't have to be working up a big sweat in the gym or become a long-distance runner to gain the benefits of exercise.''

Taking a daily pill called metformin also reduced the risk by almost a third in that study. But the new guidelines conclude there is not enough data on the benefits and risks, and thus do not recommend routine preventive medication.

The guidelines are published in the April issue of the journal Diabetes Care.

　　From nih.gov