SAN FRANCISCO – Veterans who participated in a lifestyle change program to reduce weight and increase exercise experienced a 17% lower total incidence of cardiovascular disease over 5 years, results from a large analysis demonstrated.
"Two-thirds of U.S. adults are overweight or obese, yet we know little about how to bring help to them," Sandra L. Jackson, Ph.D., said at the annual scientific sessions of the American Diabetes Association.
Lifestyle change is a recommended strategy for prevention of cardiovascular disease, but the evidence of effect of lifestyle change programs on CVD "is mixed, and few studies have had sufficient sample size to study CVD incidence as compared to change in CVD risk factors. In addition, we know little about what lifestyle change programs can achieve in health care settings, where participants are patients and providers recommend a change in lifestyle."
For the current study, she and her associates used data from the U.S. Department of Veterans Affairs’ national weight management program, MOVE! The program has enrolled more than 400,000 veterans since 2005, making it the largest lifestyle change program in the United States. Implementation varies across VA facilities, but most use a standard 10-session core curriculum, with topics that include reading food labels, reducing fat intake, evaluating portion sizes, walking with a pedometer, and setting physical activity goals.
"The program is based on principles of motivational interviewing, so VA patients are encouraged to set their own goals for physical activity and weight loss, rather than follow a set program of prescribed goals," said Dr. Jackson, who conducted the study during her doctoral work in the Nutrition and Health Sciences Program at Emory University, Atlanta. "Nearly three-quarters of patients in the VA health system are overweight or obese and in theory, could benefit from MOVE!"
The researchers evaluated MOVE! participants with data from the National VA Informatics and Computing Infrastructure, which collects data from medical records, including demographics, outpatient visits, inpatient records, diagnoses, procedures, and prescriptions, and also features statistical tools. The study included 1,463,003 eligible patients who did not have CVD at baseline. Their mean age was 52 years, 89% were men, and their mean BMI was 33.6 kg/m2. The average follow-up was about 5 years. Of the 1,463,003 patients, 169,248 were MOVE! participants and 1,293,755 were not.
Dr. Jackson reported that MOVE! participants who engaged in at least 8 sessions over 6 months lost about 2.5% of their body weight, and mostly sustained the loss over 3 years. The less active MOVE! participants lost a little over 0.5% of their body weight and maintained the loss over 3 years, while the eligible nonparticipants gained about 0.5% of body weight over the 3 years.
"Even with the substantial differences between the participant and nonparticipant groups, direct comparisons of the risk factors are hard to interpret," Dr. Jackson noted. For this reason, she and her associates used least-square means to compute averages, and adjusted for differences in baseline CVD risk factors, as well as differences in baseline BMI, age, gender, and race/ethnicity between the populations. They also stratified the analyses by diabetes status.
Systolic BP was a little lower among MOVE! participants than among nonparticipants, particularly at 6 and 12 months, "although the effect disappeared over 24 and 36 months," Dr. Jackson said. HDL cholesterol was a little higher among participants, compared with nonparticipants, while non-HDL cholesterol and plasma glucose levels were a little lower among participants, compared with nonparticipants.
Cox proportional hazards modeling revealed that there was a 17% lower incidence of CVD among participants, compared with nonparticipants (hazard ratio, 0.83). "When we looked separately at coronary artery disease, stroke, peripheral vascular disease, and heart failure, the effects remained significant," she said. These models were also adjusted for age, gender, BMI, smoking status, and a propensity score indicating likelihood of MOVE! participation, as well as other demographic and clinical characteristics.
A subgroup analysis revealed that the effect of MOVE! participation was stronger for men than for women (HR 0.83 vs. HR 0.93, respectively; P = .001).
"The VA population does have substantially fewer women than men, and women in the VA tend to be younger and may be at lower CVD risk than men," Dr. Jackson noted. "We also saw a stronger effect of participation among VA patients without diabetes, compared with those with diabetes, and we saw a stronger effect of participation among current smokers compared with nonsmokers."
Dr. Jackson said that she had no relevant financial conflicts to disclose.
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