Diet, exercise delay diabetes

At least 10 million Americans at high risk for type 2 diabetes can sharply lower their chances of getting the disease with diet and exercise, according to the findings of a major clinical trial announced by HHS Secretary Tommy G. Thompson at the National Institutes of Health.

"In view of the rapidly rising rates of obesity and diabetes in America, this good news couldn't come at a better time," said Secretary Thompson. "So many of our health problems can be avoided through diet, exercise and making sure we take care of ourselves. By promoting healthy lifestyles, we can improve the quality of life for all Americans, and reduce healthcare costs dramatically."

The findings came from the Diabetes Prevention Program, a major clinical trial comparing diet and exercise against treatment with metformin in 3,234 people with impaired glucose tolerance, a condition that often precedes diabetes, in which blood glucose levels are higher than normal but not yet diabetic.

Participants randomly assigned to intensive lifestyle intervention reduced their risk of type 2 diabetes by 58%. On average, this group maintained their physical activity at 30 minutes per day, usually with walking or other moderate-intensity exercise, and lost 5% to 7% of their body weight. Participants randomized to treatment with metformin reduced their risk of type 2 diabetes by 31%.

Smaller studies in China and Finland have shown that diet and exercise can delay type 2 diabetes in at-risk people, but the Diabetes Prevention Program, conducted at 27 centers nationwide, is the first major trial to show that diet and exercise can effectively delay diabetes in a diverse American population of overweight people with impaired glucose tolerance.

Many groups show improvement

Of the 3,234 participants enrolled in the Diabetes Prevention Program, 45% are from minority groups that suffer disproportionately from type 2 diabetes: African Americans, Hispanic Americans, Asian Americans and Pacific Islanders, and American Indians. The trial also recruited other groups known to be at higher risk for type 2 diabetes, including individuals age 60 and older, women with a history of gestational diabetes, and people with a first-degree relative with type 2 diabetes.

"Lifestyle intervention worked as well in men and women and in all the ethnic groups. It also worked well in people age 60 and older, who have a nearly 20% prevalence of diabetes, reducing the development of diabetes by 71%. Metformin was also effective in men and women and in all the ethnic groups, but was relatively ineffective in the older volunteers and in those who were less overweight," said Diabetes Prevention Program Study Chair David Nathan of Massachusetts General Hospital, Boston.

Can the interventions prevent diabetes altogether? "We simply don't know how long, beyond the three-year period studied, diabetes can be delayed," said Nathan. "We hope to follow the [Diabetes Prevention Program] population to learn how long the interventions are effective." PR