The National Institutes of Health (NIH) ended a trial designed to evaluate whether changing diet and exercise reduced cardiovascular risk factors in patients with longstanding type 2 diabetes after concluding that the intervention failed to meet that goal.
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. The study enrolled 5,145 people at 16 centers in the U.S., and randomly assigned half to an intervention that included intensive diet and exercise and half to a general program of diabetes support and education. Both groups received routine medical care.
Participants in the intervention group lost an average of more than 8 percent of their initial body weight after one year of intervention. They maintained an average weight loss of nearly 5 percent at four years, an amount of weight loss that experts recommend to improve health. Participants in the diabetes support and education group lost about 1 percent of their initial weight after one and four years.
But the study failed to demonstrate that weight loss reduced the number of cardiovascular events, Rena Wing, PhD, chair of the study and professor of psychiatry and human behavior at Brown University in Providence, R.I., said in a statement.
In September, the NIH stopped the intervention group after the study’s data and safety monitoring board found that the intensive lifestyle did no harm but did not decrease occurrence of cardiovascular events, the primary study goal. At the time, participants had been in the intervention for up to 11 years.
The board then recommended stopping the intensive lifestyle intervention early when it determined that there was little chance of finding a difference in cardiovascular events between the groups with further intervention. It encouraged researchers to continue following participants to identify longer-term effects of the intervention.
Researchers are analyzing the data to better understand cardiovascular-related results and to measure effects of the lifestyle intervention on subgroups, including racial and ethnic groups and people with a history of cardiovascular disease. Investigators are preparing a report of the findings for a peer-reviewed publication.
Although the intervention did not reduce cardiovascular events, Look AHEAD has shown other health benefits of the lifestyle intervention, including decreasing sleep apnea, reducing the need for diabetes medications, maintenance of mobility and improved quality of life, according to the NIH.