Lifestyle Called Key to Averting Diabetes
People at high risk for developing Type 2 diabetes can dramatically lower their risk of getting the disease by changing their lifestyles--even more than by taking a common diabetes drug, according to the results of a large clinical trial announced Wednesday.
The $174-million government- and industry-funded study tracked more than 3,000 diabetes-prone men and women of various ethnic backgrounds for three years. It compared the effects of a diabetes drug called metformin to that of regular exercise and changes to the participants’ diets.
The study found that the participants who made certain lifestyle changes could reduce their risk of developing the disease by 58%. They achieved this through an average of 30 minutes of daily exercise, lowering the fat in their diet and losing 5% to 7% of their body weight.
Those who took the drug but didn’t have an intensive lifestyle intervention reduced their risk by 31%.
The study stands out because of its size and the fact that it took place in the U.S., experts said. Smaller studies in Finland and China have shown lifestyle changes could help prevent diabetes, but it wasn’t clear that these findings would hold for this country’s ethnically diverse population.
In the U.S. study, 45% of the participants were from minority groups with especially high rates of diabetes, such as African Americans, Latinos and Asian Americans. The lifestyle changes helped all these groups, the study found, as well as both genders and older people.
“It’s a very important and landmark study,” said Dr. William Crowley, a professor of medicine at Harvard Medical School and president of the Endocrine Society, the world’s largest professional society for hormone specialists.
The results were so impressive that the trial ended a year earlier than was scheduled so that all patients could benefit from the findings.
The study is encouraging because it shows even modest changes in lifestyle can produce dramatic results.
“This is feasible--everybody could do it,” said Dr. Mohammed Saad, professor of medicine at UCLA and principal investigator at one of the 27 study sites. “You don’t have to go jogging or lift weights or do lots of heavy exercise. Just change your diet, lose 10 pounds, keep your weight off and walk half an hour every day.”
Patients will, however, need more than occasional reminders to achieve even these modest goals, Saad said. They will need consultations with dietitians and exercise specialists and frequent follow-ups by health care providers.
More than 16 million people in the U.S. have diabetes, and 95% of those suffer from Type 2, or adult-onset, diabetes. In this case, the body loses its ability to properly regulate levels of glucose in the blood with the hormone insulin. The result, over time, can be serious side effects, such as blindness, kidney failure, nerve damage, heart disease and stroke.
“If you prevent diabetes, you can prevent all these [related] problems,” Saad said.
But diabetes is on the rise, including among younger people, largely due to spiraling rates of obesity in the U.S. population caused by sedentary lifestyles and poor diet.
The 3,234 participants in the study, aged 25 to 85, were all overweight and had “impaired glucose tolerance”--abnormally high blood levels of glucose. This condition affects about 20 million people in the U.S. and is a precursor to diabetes. Each year, as much as 10% of people with impaired glucose tolerance develop full-blown diabetes.
Participants in the study were randomly divided into groups. In one, people were encouraged to make lifestyle changes. They took classes for 24 weeks and were closely monitored in various ways in the months that followed. They also were invited to participate in activities such as competitions and group walking events. The aim was a 7% drop in weight and 150 minutes of exercise weekly.
Another group was given the drug metformin, which was approved to treat Type 2 diabetes in 1995, to see whether it could also prevent diabetes. A third group was given a placebo. Both of the latter groups were given general advice about weight loss and exercise.
After an average of three years, 29% of the group getting the placebo had developed Type 2 diabetes. Only 14% of the lifestyle intervention participants and 22% of the group taking metformin had done so.
In a sense, the study results aren’t surprising, said Dr. Ronald Stein, clinical professor at the USC School of Medicine, since the link between obesity and diabetes is widely appreciated by doctors. But it can be very difficult to get patients to make even modest changes to their lives.
“You encourage them to do these things. Unfortunately, I’m somewhat pessimistic about the amount of good we accomplish,” he said.
The challenge, experts say, is translating these results into workable programs that can be applied in doctors’ offices all over the country. To help with this, the National Diabetes Education Program, sponsored by the government and public and private organizations, is devising educational materials and strategies for health care providers and the public.
