Diabetes control and cardiovascular risks sustained over 4 years
An intensive lifestyle intervention program designed to achieve and maintain weight loss improves diabetes control and cardiovascular disease risk factors in overweight and obese individuals with type 2 diabetes, according to four-year results of the Look AHEAD study, funded by the National Institutes of Health and the Centers for Disease Control and Prevention. The results are published in the Sept. 27, 2010, issue of the Archives of Internal Medicine.
Look AHEAD (Action for Health in Diabetes) is a multi-center, randomized clinical trial investigating the effects of an intensive lifestyle intervention program. It will evaluate the effect of reduced caloric intake and increased physical activity on the incidence of major cardiovascular events such as heart attack, stroke, and cardiovascular-related death.
At study entry, 5,145 participants at 16 centers across the United States were randomly assigned to one of two interventions. Those in a so-called "intensive lifestyle intervention group" met regularly with a lifestyle counselor in a combination of group and individual sessions. They were given specific caloric consumption and exercise goals, were encouraged to maintain a diet and exercise diary, and were taught behavioral skills such as problem solving and goal setting. After the first year, participants were seen individually at least once monthly, had at least one additional phone or email contact each month, and were invited to attend additional group classes. Those in the "diabetes support and education group" were invited to group sessions each year focused on diet, physical activity, or social support. They were not weighed at these sessions or counseled on behavioral strategies.
At the time of enrollment, participants were between 45 and 76 years of age. Most were obese with a mean body mass index (BMI) of 36. BMI is a measure of weight in relation to height. A BMI of 18.5 to 24.9 is considered healthy, a BMI of 25 to 29.9 is overweight, and 30 or more is obese. Thirty-seven percent of participants were from racial and ethnic minority groups, and approximately 60 percent were women. Over 94 percent of participants remain involved after four years and will continue to be followed for up to 13.5 years.
Over the first four years of Look AHEAD, participants in both groups showed positive changes in their health. On average, across all four years, participants in the intensive lifestyle group lost significantly more weight than participants in the support and education group. On average, members of the lifestyle group lost 6.2 percent of their initial body weight, and members of the support and education group lost 0.9 percent of their initial body weight. The intensive intervention group also experienced greater improvements in fitness, diabetes control, blood pressure, HDL (good) cholesterol, and triglycerides. The diabetes support group showed larger reductions in LDL (bad) cholesterol, a change associated with the increased use of cholesterol-lowering medications. The study results do not break down results by demographic groups such as gender, age, race or ethnicity.
"This important study shows that lifestyle changes have long-term favorable effects on diabetes control and cardiovascular disease risk factors in overweight or obese individuals with type 2 diabetes," said Griffin P. Rodgers, M.D., director of the National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK), the primary sponsor of the study.
"It is important to note that participants in the intensive lifestyle group and the diabetes education and support group have had positive changes in their weight and their cardiovascular risk factors over the four years," said study chair Rena Wing, Ph.D., of the Miriam Hospital/the Warren Alpert Medical School of Brown University in Providence, R.I.
Longer-term follow-up of Look AHEAD participants will determine whether improvements in risk factors including blood pressure, lipids and glucose control can be sustained -- independently and as a consequence of continued weight loss -- and whether the intensive lifestyle intervention is effective in reducing the incidence of illness and death due to cardiovascular disease. These results will not be available for several years. Other important study objectives include understanding the impact of weight loss and improved fitness on diabetes complications, general health, quality of life, and psychological outcomes. Researchers also will evaluate the cost and cost-effectiveness of the intensive lifestyle intervention compared to diabetes support and education.
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