Weight loss and increased physical fitness nearly halved the risk of losing mobility in overweight or obese adults with type 2 diabetes, according to four-year results from the Look AHEAD (Action for Health in Diabetes) trial funded by the National Institutes of Health. The results are published in the March 29, 2012, issue of the New England Journal of Medicine.
"Being able to perform routine activities is an important contributor to quality of life," said Griffin P. Rodgers, M.D., director of the NIH's National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK), which led the study. "These findings add support to making lifestyle changes that improve health and reduce disability in people with type 2 diabetes, changes that already have been shown to prevent the disease and provide a good return on investment."
Look AHEAD is a multi-center, randomized clinical trial designed to determine the long-term effects of intentional weight loss on the risk of developing cardiovascular disease in overweight and obese individuals with type 2 diabetes. Beginning in 2001, a total of 5,145 participants were randomly assigned to either an intensive lifestyle intervention group (ILI) or a diabetes support and education group (DSE). Participants receiving the intervention attended group and individual meetings to achieve and maintain weight loss through decreased caloric intake and increased physical activity. The DSE group attended three meetings each year that provided general education on diet, activity, and social support.
To assess mobility and disability, participants rated their ability to carry out activities with or without limitations. Included were vigorous activities such as running and lifting heavy objects and moderate ones such as pushing a vacuum cleaner or playing golf. Participants also separately rated their ability to climb a flight of stairs; bend, kneel or stoop; walk more than a mile; and walk one block. Both groups were weighed annually and completed a treadmill fitness test at baseline, after one year, and at the end of four years.
After four years of the study, participants in the ILI group experienced a 48 percent reduction in mobility-related disability compared with the DSE group. Furthermore, 20.6 percent of ILI participants reported severe disability compared to 26.2 percent of participants in the DSE group. Likewise, 38.5 percent of those in the ILI group reported good mobility, whereas the rate was 31.9 percent in the DSE group. Weight loss was a slightly stronger predictor of better mobility than improved fitness, but both contributed significantly to the observed reduction in risk.
"With nearly two-thirds of participants reporting mild, moderate, or severe restrictions in mobility when Look AHEAD began, it is critical to address this problem," said Mary Evans, Ph.D., project scientist for the study. "This study of mobility highlights the value of finding ways to help adults with type 2 diabetes keep moving as they age. We know that when adults lose mobility, it becomes difficult for them to live on their own, and they are likely to develop more serious health problems, increasing their health care costs."
Overweight and obesity affects more than two-thirds of U.S. adults age 20 and older. More than one-third of adults are obese. Many factors contribute to the problem, including genetics, lifestyle habits, and the food environment. Excess weight can lead to type 2 diabetes, heart disease, high blood pressure, stroke, and certain cancers. Nearly 26 million Americans have diabetes, and 7 million of them do not know it.
"The weight loss and physical activity goals promoted in the study are well within the reach of most Americans," said Jack Rejeski, Ph.D., lead author and Thurman D. Kitchin professor of health and exercise science at Wake Forest University, Winston-Salem, N.C. "Future research is needed to determine if this sort of intervention can be translated into public health interventions, particularly in light of possible effects on health care costs."