MORE THAN 40 PERCENT of middle-aged and older Americans have a problem that can cause long-term damage to the heart and blood vessels, and most don't know they have it.
The problem is being found even in children: Physicians at Yale have found that 25 percent of obese kids have prediabetes.
Prediabetes is poorly controlled blood sugar that is not abnormal enough to be considered diabetes. If not treated with lifestyle changes, most people with prediabetes will develop full-blown Type 2 diabetes within 10 years.
That's a problem because diabetes' complications can include heart attack, stroke, blindness, kidney failure, amputations and erectile dysfunction. Even prediabetes raises the risk of heart disease by 150 percent and can cause nerve pain.
However, these complications can be avoided, and people can live long, healthy lives, if they treat their diabetes or prediabetes.
"For some people with prediabetes, intervening early can actually turn back the clock and return elevated blood glucose levels to the normal range," according to the American Diabetes Association.
Many people at riskEveryone who is 45 or older should have a blood test for diabetes at a doctor's office, according to the National Institutes of Health.
Younger people should have a blood test if they are overweight and have one or more of the following risk factors: exercise less than three times a week; ethnicity not Caucasian; a parent or sibling with diabetes; history of gestational (pregnancy) diabetes or had a baby weighing more than 9 pounds; high blood pressure; HDL or "good" cholesterol less than 40 for men or less than 50 for women; high trigylcerides; polycystic ovarian syndrome; or history of heart or circulation problems.
Blood tests for diabetes include a fasting blood sugar test, in which blood is drawn in the morning before breakfast; and the oral glucose tolerance test, which involves drinking a special sugary drink before the blood test.
If your test is normal, you need to be rechecked every three years, according to the American Diabetes Association.
If your test shows prediabetes, you should be checked for Type 2 diabetes every year or two, and you can take action to prevent diabetes from developing.
Trio of prevention tipsStudies prove that three changes can help:
Moderate exercise, such as walking for at least 30 minutes, five days a week, is essential.
Decreasing fat intake to less than 25 percent of calories.
If you are overweight, a modest weight loss of 5 to 7 percent can decrease your risk.
Changes really workA Finnish study of intensive, individualized diet and exercise counseling showed that individuals' rate of getting diabetes dropped 58 percent compared to those who didn't get intense counseling.
The men studied were counseled to lose 5 percent of their weight, eat a diet low in fat and saturated fat, increase fiber and exercise 150 minutes per week. They had seven sessions with a nutritionist during the first year of the study, and one session every three months thereafter. They also received individualized guidance on increasing physical activity, and half worked with a trainer at an exercise club.
An American study of more than 3,000 people, known as the Diabetes Prevention Program, found the same 58 percent drop in new cases of diabetes among people who got intense counseling about reducing fat in foods, as well as exercise, self-monitoring, goal- setting and problem-solving.
The counseling included meetings with a case manager 16 times over the first six months and then monthly meetings and phone calls thereafter. People in the study could attend classes on exercise and weight loss, and two supervised exercise sessions were offered each week. Some received incentives, such as exercise tapes or equipment, access to exercise equipment, free low-calorie foods, more structured eating plans and home visits.
Nutrition, fitness trump drugsThe same study found that the diabetes drug Glucophage reduced risk of developing diabetes by 31 percent in overweight people, which is about half as effective as lifestyle changes.
Another study found another diabetes medicine, Precose, reduced the risk of developing diabetes by 25 percent.
The weight-loss medication Orlistat also shows some promise, as do a few blood-pressure medications and one cholesterol drug. But there is not enough evidence yet to recommend them, according to a recent article in The Journal of the American Board of Family Practice.
Gastric bypass surgery can reduce the risk of diabetes, but it is expensive, has complications, and is not suitable for many people.
Because changing eating habits and physical activity is twice as effective as drugs, the federal government launched a campaign, "Small Step, Big Rewards: Prevent Type 2 Diabetes." You can request free booklets and CDs in English and many other languages by calling the National Diabetes Education Program at 800/438-5383 or visiting ndep.nih.gov.
It's difficult to change someone's life in an hour. Studies show that people who receive several counseling sessions about nutrition and exercise are more likely to succeed.
JENNIFER MOTL, a registered dietitian, welcomes reader questions. E-mail her by filling out a form at brighteating.com; or write to Nutrition, The Free Lance-Star, 616 Amelia St., Fredericksburg, Va. 22401.