Lifestyle Changes Ward Off Type II Diabetes
Large U.S. clinical trial finds a little weight loss and exercise can cut your risk in half
THURSDAY, Aug. 9, 2001 (HealthDayNews) -- Shedding just a few pounds and getting only a modicum of exercise can dramatically cut your chances of getting Type II diabetes, according to the largest-ever U.S. clinical trial on diabetes prevention.
Americans at high risk for Type II (adult-onset) diabetes, which is now at epidemic levels in the United States, can decrease their risk of getting the disease by almost 60 percent if they lose only 15 pounds on a low-fat diet and exercise 30 minutes a day for five days a week.
The lifestyle changes can be even more dramatic for people over 60: diet and exercise can slash their risk by 71 percent.
The three-year results of the government-sponsored clinical trial were considered so statistically significant that the data safety monitoring board, charged with oversight of the study, ended the effort a year early to allow researchers at the National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK) to announce the findings.
"This study shows that small changes make a huge difference in reducing risk," says Dr. Judith Fradkin, director of the NIDDK division of diabetes, endocrinology and metabolic diseases, which ran the trial.
"These small changes work across the board, no matter what weight you are, no matter what sex you are, no matter what race you are," Fradkin adds.
The findings from the Diabetes Prevention Program (DPP) come from research that tracked the effects of diet, exercise and treatment, along with the diabetes drug metformin, in 3,234 people with impaired glucose intolerance (IGT) at 27 centers across the United States. IGT is identified by higher-than-normal blood sugar levels without any of the symptoms of diabetes, and is considered a precursor to adult-onset diabetes.
The Food and Drug Administration approved metformin, sold under the trade name Glucophage, in 1995 to treat Type II diabetes.
The volunteers were divided into three groups: one group underwent lifestyle changes -- a low-fat diet and 150 minutes of exercise a week -- aimed at reducing their body weight by 7 percent; another group took 850 milligrams of metformin twice daily; and the third took a placebo instead of the metformin. The two latter groups received information on diet and exercise.
Those assigned to lifestyle intervention reduced their risk of getting Type II diabetes by 58 percent, Fradkin says. About 29 percent of the group given placebos developed diabetes within three years, 22 percent of those who took metformin did also, compared to only 14 percent of the lifestyle group.
The average age of the participants was 51, and 45 percent were from minority groups known to be prone to diabetes: African-Americans, Hispanic-Americans, Asian-Americans, Pacific Islanders and American Indians. The clinical trial also included people over the age of 60, women with a history of gestational diabetes, and people with a first-degree relative suffering from Type II diabetes. Gestational diabetes occurs during pregnancy and usually disappears after childbirth.
Lifestyle intervention worked as well in men as it did in women, and had the same positive effects in all the ethnic groups.
For people over the age of 60, where almost 20 percent have Type II diabetes, exercise and diet slashed the risk by 71 percent. Metformin was generally ineffective in the older volunteers and those who were less overweight, the trial shows.
"It's generally a confirmation of what we know," says Dr. Robert Sherwin, a professor of medicine at Yale University School of Medicine and the immediate past president of the American Diabetes Association. Sherwin was also the chairman of an advisory committee that will explore how the program can be translated into public policy.
"The study shows that avoiding the risk of Type II diabetes does not require incredible changes in lifestyle," Sherwin continues. "You don't have to run around the track all day or starve yourself. You can lose 10 pounds and walk briskly for 30 minutes a day and prevent the disease."
More than 16 million Americans have been diagnosed with Type II diabetes, and the incidence of the disease has tripled in the last 30 years, according to the NIDDK. Obese people -- those with a body mass index of 30 or greater -- have a fivefold greater risk for developing diabetes than those who are of normal weight. Diabetes is the main cause of kidney failure, limb amputations, and new cases of blindness in adults. It is also a major cause of heart disease and stroke.
Fradkin and Sherwin say no one knows how long diet and exercise can stave off Type II diabetes.
"We simply don't know how long, past the three-year period studied, diabetes can be delayed," Fradkin says. "We're hoping to continue to follow this group of volunteers, and we are certainly hopeful that diet and exercise will continue to be effective. But even delaying the disease for three years will make a huge difference. If you can delay a heart attack or eye disease or a limb amputation three years later in your life, that's big."
Sherwin agrees. "Just the effect on public policy and public health would be enormous," he says. "But if people keep the pounds off, and they continue to exercise, we're pretty confident that it will have a longer lasting effect."
What To Do
These findings show that you don't have to change your lifestyle radically to fend off this disease.