NIH Report: Weight Loss Does Not Lower Heart Disease Risk in Patients With Type 2 Diabetes
Lifestyle intervention stopped early in overweight adults after finding no cardiovascular benefits (Oct. 19)
An intensive diet and exercise program resulting in weight loss does not reduce cardiovascular events, such as heart attack and stroke, in people with longstanding type 2 diabetes, according to a study supported by the National Institutes of Health (NIH).
The Look AHEAD (Action for Health in Diabetes) study tested whether a lifestyle intervention resulting in weight loss would reduce rates of heart disease, stroke, and cardiovascular-related deaths in overweight and obese people with type 2 diabetes — a group at increased risk for these events.
A total of 5,145 individuals in the U.S. were randomly assigned to receive an intensive lifestyle intervention or a general program of diabetes support and education. Both groups received routine medical care from their own healthcare providers.
Although the lifestyle intervention did not reduce cardiovascular events, the Look AHEAD study showed other important health benefits, including decreasing sleep apnea, reducing the need for diabetes medications, helping to maintain physical mobility, and improving quality of life.
Participants in the intervention group lost an average of more than 8% of their initial body weight after 1 year of intervention. They maintained an average weight loss of nearly 5% at 4 years — an amount of weight loss that experts recommend to improve health. Participants in the diabetes support and education group lost about 1% of their initial weight after 1 and 4 years.
In September 2012, the NIH stopped the study’s intervention arm, acting on the recommendation of a data and safety monitoring board. The board found that the intensive lifestyle intervention did no harm but did not decrease the occurrence of cardiovascular events — the primary study goal. At the time, participants had been in the intervention group for up to 11 years.
Because there was little chance of finding a difference in cardiovascular events between the two groups with further intervention, the board recommended stopping the intensive lifestyle intervention, but encouraged the study to continue following all participants to identify longer-term effects of the intervention.
Type 2 diabetes affects nearly 24 million people in the U.S., and its prevalence has increased along with the country's epidemic of overweight and obesity. Cardiovascular diseases are the most common cause of death among people with type 2 diabetes.
Look AHEAD is the first study to examine the long-term effects of a lifestyle intervention on major cardiovascular disease events and death in adults with type 2 diabetes. Participants were 45 to 76 years old when they enrolled in the study. Sixty percent of enrollees were women, and more than 37% were from racial and ethnic minority groups.
Source: NIH, October 19, 2012.