By Chad Hudnall

October 2005

Susan McCarthy has struggled with her weight for most of her 52 years. She has always known that carrying too many extra pounds could lead to serious health problems. "But I never ever thought I was at risk for diabetes," she says. "No one in my family ever talked about it, and I never heard of any of them having it."

Then five years ago McCarthy's doctor tested her for the disease. The level of sugar in her blood was abnormally high but not high enough for a diagnosis of diabetes.

McCarthy, a project manager at the U.S. Department of Agriculture and a resident of Laurel, Md., was diagnosed with prediabetes, meaning that without treatment she had a 30 percent chance of developing type 2 diabetes within three years and at least a 50 percent chance within 10 years, according to the National Institute of Diabetes and Digestive and Kidney Diseases.

It's a condition affecting a startling number of American adults—two of five adults ages 40 to 74, some 41 million Americans, according to American Diabetes Association (ADA) guidelines revised in 2003 [see below]. The statistics reflect an aging population that is increasingly overweight and sedentary.

"The new numbers are very daunting," says Trevor Orchard, M.D., professor at the Graduate School of Public Health, University of Pittsburgh, and a lead investigator in the Diabetes Prevention Program, a landmark weight loss and exercise trial program conducted through the National Institutes of Health in the 1990s.

Today 18 million adults have type 2 diabetes. If current rates of diabetes and prediabetes continue, that number could surge to 30 million—roughly the combined population of the 20 largest U.S. cities—as soon as 2030, researchers say. As diabetics, they'll run the risk of cardiovascular disease, kidney failure, high blood pressure, stroke, blindness and amputation. Studies also show a connection between diabetes and accelerated dementia, especially in women.

And the financial damage? Over the next 15 years, the ADA estimates, the annual cost of diabetes in the United States will rise to $192 billion, greater than the national budgets of all but a few countries.

It doesn't have to be that way.

"Diabetes is a very serious disease, but there is a huge window of opportunity for people with prediabetes to take action through lifestyle changes," says K.M. Venkat Narayan, M.D., with the Centers for Disease Control and Prevention's Division of Diabetes Translation. Even minimal physical activity and weight control, he says, can impede full-blown diabetes.

After her diagnosis, McCarthy set out to lower her blood sugar and lose weight. A dietitian recommended changes in her eating habits; she began walking for exercise. "I started monitoring my blood glucose level, and within a month it was getting back to a normal range."

She still faced the challenge of keeping it there.

Diabetes is all about managing sugar, the basic fuel for the body's cells. Insulin, produced by the pancreas, delivers glucose from the blood to the cells. Diabetics either don't produce enough insulin (type 1, usually diagnosed in childhood) or, most commonly, can't use it properly (type 2). When sugar doesn't reach cells, it builds up in the blood, and the underfueled cells are starved for energy.

African Americans, Latinos, Native Americans and other ethnic minorities are especially at risk. Members of Arizona's Pima tribe have the nation's highest rate of both obesity and diabetes. Relying on farming, hunting and fishing for food for thousands of years, the Pima adapted to alternating periods of feast and famine by developing a "thrifty gene," which stores fat. Once a lifestyle with unlimited calories and less physical activity overtook them, most researchers conclude, diabetes became a problem. Not so for their close relatives across the Mexican border who continue to practice their traditional ways.

Mexican American José Cortez, 57, credits his wife, Tina, 42, who is an Arizona Pima, for his awareness of their shared risk. "Knowing that many members of her family have died from that disease made us more aware of a very real and dangerous situation," says Cortez, who works for a Phoenix community development corporation and frequently speaks to Latino groups about diabetes.

A family history of diabetes almost guarantees high risk. In 1986 a cerebral hemorrhage related to diabetes killed Jim Reeder's father at age 63. Eight years later Reeder, 57, a sporting goods sales manager living in Arlington, Texas, discovered he had prediabetes.

"I was worried after seeing what my dad went through," Reeder says. "My blood sugar wasn't out of sight, but I went on a diet and an exercise program." With his strong personal motivation to remain prediabetic, Reeder lost about 30 pounds, started getting tested more often and lowered his levels back into a normal range.

A diagnosis of prediabetes demands a thorough life change. Once a diabetic, always a diabetic, but by adjusting their diet and exercise, prediabetics often quickly lower their blood sugar levels. A small weight loss—5 to 7 percent—deters diabetes in more than 71 percent of prediabetics age 60 and over, according to the Diabetes Prevention Program.

Medical experts generally agree that even modest exercise can produce big results. The program recommends 30 minutes of activity five times a week. Medication such as metformin, which increases insulin sensitivity and decreases blood sugar production, can also help delay diabetes, but not as effectively.

Of course, old habits die hard. Even under the threat of serious disease, most diabetics don't adequately control their blood sugar, according to a recent study by the American Association of Clinical Endocrinologists.

Susan McCarthy has learned firsthand the consequences of losing focus. After keeping her blood sugar down for several years, she lapsed into old ways. She went out to eat more often and started taking the elevator instead of walking up stairs. Her weight rose higher than ever, and she was diagnosed with diabetes.

"The first time you hear that you're prediabetic, you need to act, and act swiftly and strongly so that you don't trip over into full diabetes," McCarthy says. "I didn't have enough information about the consequences. My life got stressful, and I slipped up."

Through frequent doctor visits and multiple prescriptions, she manages her life with diabetes in good spirits and has dropped close to 100 pounds. "I have become friends with a large range of medical practitioners," she jokes. "Still, my biggest motivation is that I don't want to have the other health complications that can come with my diabetes."

The Cortezes have adapted their love of the outdoors into their fitness program for maintaining safe blood sugar levels. They hike a nearby mountain peak—a 1.2-mile trek—between three and five times a week. José usually goes before the sun comes up; Tina prefers the evenings.

Reeder continues to stay away from fat—fried foods and desserts, what he calls "all the tasty stuff"—although he admits he has regained 10 of the 30 pounds he lost. Still, for 11 years his blood sugar has remained below diabetic levels.

"I'm staying faithful to it," he says. "I had the impetus from my dad, and it's a very good feeling to know that you can be in control of it."

Additional Related Links

Why the Number of Prediabetes Patients Is Rising

Diabetes Resource Guide