US: Encouraging weight loss and physical activity for people with diabetes
Title: Lifestyle change and mobility in obese adults with type 2 diabetes
Authors: W Rejeski, E Ip, A Bertoni, G Bray, et al.
Reference: N Engl J Med 2012; 366:1209-17
Reviewer: Robert Goldberg, PhD, Contributing editor, ProCor; Professor of Medicine and Epidemiology, Division of Cardiovascular Medicine, University of Massachusetts Medical School, Worcester, Massachusetts, USA
Reviewer comments: Diabetes is an ever-increasing public health problem throughout developed and developing nations. While diabetes has been consistently associated with an increased risk for developing and dying from CVD, many people with type 2 diabetes are limited in their activities of daily living, primarily through the loss of mobility. The increased body mass index (BMI) associated with this prevalent metabolic disorder further increases the risk of disability, impaired ambulation, and reduced quality of life.
The results of this large randomized controlled trial (RCT) (Look AHEAD) of overweight and obese middle-aged adults (age 45-74 years) with type 2 diabetes demonstrate that an intensive lifestyle intervention can slow the rate of decline associated with mobility in these high risk individuals. Both enhanced weight loss and improved cardiorespiratory fitness through an extended exercise program were the two key mediators of the favorable effects associated with the lifestyle intervention utilized.
The present results provide encouragement for these difficult to manage patients demonstrating that an intensive lifestyle intervention can result in weight loss, improvement in aerobic fitness, and slowing down of the decline in mobility associated with the aging process and elevated serum glucose levels. The results of this large RCT need to be translated into everyday clinical practice, as this is encouraging news for adults with type 2 diabetes mellitus. Physicians and other health care providers should attempt to adopt the lifestyle intervention used in the present trial to encourage their patients with diabetes to lose weight and begin a program of regular physical activity with steady increases in duration over time, with benefits on the control of serum glucose levels, patient's quality of life, and other positive health effects including their ability to engage in regular daily activities.
Purpose of study: To examine the effects of an intensive lifestyle intervention on the mobility status of obese middle-aged adults with type 2 diabetes
Location of study: US
Study design: Randomized controlled trial
Results: The Look AHEAD (Action for Health in Diabetes) trial is a large multi-center RCT that enrolled overweight or obese adults age 45-74 years with type 2 diabetes. These people were randomly assigned to either an intensive lifestyle intervention or to a diabetes support and education program. The primary goals of the intensive lifestyle intervention were to induce an average weight loss from the time of baseline enrollment of more than 7% and to increase the duration of physical activity to approximately three hours weekly. Mobility was assessed through use of the SF-36 health survey physical functioning subscale. Patients in the diabetes support and education comparison group met three times a year as a group and these group sessions focused on nutrition, physical activity, and support.
A total of 5016 individuals were included in the present analyses. The average age of study subjects was 59 years, 60% were women, approximately two-thirds were white, and their average BMI was 36.
In the subgroup of participants that had changes in their physical activity assessed from the time of baseline trial enrollment, the average increase in energy expenditure was 881 kcals/week in the lifestyle/intervention group and only 99 kcals/week in the diabetes support group; at year one, these average increases in energy expenditure were 358 and 96 kcals/week, respectively, in the two comparison groups. In addition, the average weight loss during the trial was 6.2% in the lifestyle intervention group compared with 0.9% in the diabetes support group.
In terms of the loss of mobility, the lifestyle intervention group had a relative reduction of 48% in the risk of loss of mobility as compared with those in the diabetes support group. The prevalence rates of those with severe mobility related disability in the lifestyle intervention group were 12.3% and 20.6% at one and four years, respectively, compared with 18.9% and 26.2% at these 2 time points for those in the support group only. At four years, the prevalence of good mobility was 38.5% in the lifestyle intervention group in comparison with 31.9% in the support group.
The mediation effects of weight loss and improved fitness were statistically significant, resulting in a lower risk of loss of mobility. For example, for every relative reduction of 1% in weight, and relative improvement of 1% in fitness, the risk of the loss of mobility was reduced by 7.3% and 1.4%, respectively.