When she worked as a journalist in Palo Alto, Loren Stein, then 44, never gave much thought to diabetes. "My image of a diabetic was someone who ate a ton of sugar and was really overweight," she says. "I never put myself in that category."
Stein got a wake-up call during a routine checkup. Her fasting blood sugar level was 119 milligrams of glucose per deciliter of blood, significantly higher than the normal range of 70 to 99. She didn't have diabetes, but she was headed in that direction. "I was shocked," she says. "I thought it must be a mistake."
According to the American Diabetes Association, up to 79 million Americans have a little too much sugar in their blood, a condition that makes them prime targets for type 2 diabetes. In medical-speak, these people have "impaired glucose tolerance" or "impaired fasting glucose," now referred to as prediabetes.
Impaired fasting glucose was first defined as a fasting glucose of 110 to 125 milligrams of glucose per deciliter of blood, but in 2003 the cutoff for prediabetes dropped to 100 milligrams of glucose per deciliter. Prediabetes can be defined as impaired fasting glucose (100 mg/dL to 125 mg/dL), impaired glucose tolerance, or both. Whatever term you use for prediabetes, the condition is a call for action. Several recent studies have shown that a healthy lifestyle can help keep prediabetes from turning into the real thing. If you've been diagnosed with this condition, the ball is in your court.
The road to diabetes
Aside from fats or protein, just about everything you eat is broken down into sugars (glucose is the simplest sugar). After a meal, the sugar is absorbed into the bloodstream, where it is carried to energy-starved cells. A hormone called insulin helps maintain a healthy balance of sugar in your blood. If glucose levels start to climb too high, insulin signals your cells to take in the extra sugar.
Unfortunately, insulin doesn't always work as well as it should. Many people start to lose sensitivity to the hormone, a condition called insulin resistance. This condition is especially common in people who are overweight or inactive. As insulin begins to lose its power, the amount of sugar in the blood slowly rises. People with fasting blood sugar levels that are above normal but not in the diabetic range have impaired fasting glucose, or prediabetes.
According to an expert panel convened by the ADA and the U.S. Department of Health and Human Services, most people with prediabetes will develop full-blown diabetes within 10 years -- unless they take action. Prediabetes is also dangerous in its own right. Several years ago, the panel reported that blood sugar levels slightly above normal increase the risk of a heart attack or stroke by 50 percent.
A silent condition
Prediabetes often has no symptoms. You may never know you have it unless a doctor conducts a blood test. Doctors may give you an A1C test to measure your average blood sugar level over the last two to three months, or do other tests such as a fasting glucose test. Because blood sugar levels rise and fall naturally depending on your eating schedule, your doctor may ask you to fast overnight before checking your blood. (This is the test that Stein had.) Another option is to have your sugar levels checked two hours after you drink a certain amount of glucose. Either test will provide a picture of your body's ability to control sugar.
The diabetes association says everyone over 45 should at least consider having their glucose (blood sugar) level tested. As the risk of diabetes grows, so does the need for testing. If you're older than 45 and overweight, "considering" such a test isn't enough. If you haven't already had the fasting plasma glucose test, make an appointment. Generally, you're considered to have diabetes if your A1C on two separate tests is 6.5 or higher, or if your glucose reading after fasting -- confirmed by a second test -- is 126 or higher, or if you have a level of more than 200 plus symptoms of high blood sugar.
According to the ADA, the test is also a good idea for anyone under 45 who is overweight and has another risk factor for diabetes or heart disease. These include high cholesterol, high blood pressure, a family history of diabetes, a personal history of gestational diabetes (diabetes only during a pregnancy), having given birth to a baby that weighed more than 9 pounds, or belonging to a non-Caucasian racial group. (Caucasians have the lowest risk for diabetes.)
If the test results come back normal, you can wait up to three years before being retested -- unless your doctor recommends testing more frequently due to an increased risk of diabetes.
When Stein was diagnosed with impaired fasting glucose, her doctor laid out a clear course of action. First of all, she needed to add exercise to her daily routine. (Exercise helps burn extra sugar.) And even though she wasn't obese, she learned that she could stand to lose a little weight. "I was newly married, and my husband loves to cook," she says.
Stein took the advice to heart. She joined Weight Watchers, improved her diet, and started going to the gym. Within a few months, she had lost 15 pounds.
As two research projects show, such lifestyle changes add up to powerful protection against diabetes. A study of 3,234 patients, published in the New England Journal of Medicine, found that a healthy lifestyle (150 minutes of moderate exercise each week combined with a low-fat, high-fiber diet) cut the risk of diabetes by 58 percent. Since low serum 25-hydroxyvitamin D has been linked with prediabetes, some doctors also suggest taking vitamin D supplements.
An earlier three-year study of 522 Finnish men, published also in the New England Journal of Medicine, produced equally impressive results. In this group, diet and exercise once again cut the risk of diabetes by 58 percent.
If you have prediabetes, there's a simple recipe for good health. Studies show at least 150 minutes a week of moderate physical activity (such as walking or jogging) and a diet that's low in fat and rich in produce and whole grains can help prevent or delay diabetes. If you're overweight, losing just 5 percent to 10 percent of your body weight can make a big difference.
Unfortunately, lifestyle changes don't always stick. After starting a new job, Stein had trouble finding the time to work out. As the months went by, anxieties about diabetes returned. In fact, she was afraid to go back to the doctor and have another blood test.
That spring, she decided she couldn't put off that test any longer. When the results came in a few days later, she had reason to celebrate: Her glucose level was well within the normal range. Even better, she learned that her cholesterol levels had also improved since her last appointment.
Good news from the doctor can have one of two effects. Some people decide to keep up the good work, and others let down their guard. At this point, Stein isn't sure which way she's leaning. "There's a part of me that wants to say it won't be a problem again," she says. For now, she plans to eat carefully and watch her weight. And if she ever gets another wake-up call, she'll know what to do.
Interview with Loren Stein, prediabetes patient
American Diabetes Association. Pre-Diabetes. http://www.diabetes.org/pre-diabetes.jsp
American Diabetes Association. The prevention or delay of type 2 diabetes. Diabetes Care. Vol. 25: 742-749.
Tuomilehto, J. et al. Prevention of type 2 diabetes mellitus by changes in lifestyle among subjects with impaired glucose tolerance. New England Journal of Medicine. Vol. 344 (18): 1343-1350.
Revised Definition Means Millions More Have Pre-Diabetes. HHS Press Release. April 29, 2004