A new randomized clinical trial, led by a team of researchers from Wake Forest University School of Medicine and Wake Forest University, did not find evidence that wearing a weighted vest or engaging in resistance training prevented bone loss in older adults undergoing intentional weight loss.
The study, published today in JAMA Network Open, underscores the persistent need for alternative strategies to protect skeletal health in aging populations with obesity.
While weight loss is commonly advised to enhance cardiovascular and joint health in older adults with obesity, it may also lead to bone loss, raising the risk of fractures that can diminish both quality and longevity of life.
The 12-month INVEST in Bone Health trial enrolled 150 older adults with obesity with a mean age of 66.4 years. Participants were randomized into three groups: weight loss alone, weight loss plus daily weighted vest use and weight loss plus resistance training. All groups achieved similar, significant weight loss (9% to 11.2% of body weight), and adherence to interventions conducted at Wake Forest University was high.
The INVEST research team represents a multidisciplinary collaboration of Wake Forest University’s departments of Health and Exercise and Statistical Sciences with Wake Forest University School of Medicine’s departments of Internal Medicine, Biomedical Engineering, Biostatistics and Data Science, and Radiology.
The researchers set out to expand on the findings of a pilot study, in which participants wearing weighted vests seemed to mitigate bone loss that accompanies weight loss in this population.
However, all three INVEST study groups experienced a similar rate of significant decreases in hip bone mineral density.
“While we hoped that replacing lost weight externally or increasing mechanical loading through exercise would preserve bone, but our findings show that these strategies alone may not be enough,” said Kristen M. Beavers, Ph.D., M.P.H, R.D. the study’s corresponding author and professor of internal medicine, section of gerontology and geriatric medicine, at Wake Forest University School of Medicine and research professor of health and exercise science at Wake Forest University.
The weighted vest group wore the vest for an average of 7.1 hours per day, replacing approximately 78% of lost weight. The resistance training group attended 71% of the prescribed sessions.
Beavers said the study highlights the complexity of managing obesity in older adults, where the benefits of weight loss must be balanced against potential harm to bone health and need to consider alternate or adjuvant countermeasure strategies. An ongoing collaboration between Wake Forest University and Wake Forest University School of Medicine researchers is studying how an osteoporosis drug might help. That study is called the Bone, Exercise, Alendronate, and Caloric Restriction (BEACON) trial.
The INVEST in Bone Health findings are in no way a reason to stop using weighted vests in exercise regimens, Beavers said, and more than half of study participants said they did not mind using them. Studies have shown that, in addition to helping older adults lose weight, such vests also help improve strength and sit-to-stand performance, a key predictor of disability. INVEST was based on a body of research showing that wearing weighted vests during exercise can improve strength, reduce bone loss and improve muscle performance.
Bone health is only one predictor of fractures. Beavers said INVEST also points to the potential role of preserving lean muscle mass as a protective factor for bone health.
“Fractures in older adults can be life-altering,” she said. “Our study reinforces that we need to think beyond traditional exercise and consider new or combined approaches to protect bone during weight loss.”
INVEST in Bone Health is the latest in a series of Wake Forest University research studies on safe weight loss for older adults. Scientists there have studied, for instance, the effects of higher-protein diets, resistance training and community-based programs in weight-loss interventions for this population.
The timing of such research is vital: It’s estimated that 72 million Americans will be age 65 or older by 2030, and the majority of them will be overweight or obese. Moreover, Beavers said the emergence of new and highly effective weight-loss medications, such as Wegovy and Mounjaro, have raised concerns about the bone loss that accompanies rapid weight loss in this population. Developing safe, effective weight-loss protocols for older people is essential to supporting independent living and quality of life.
The INVEST research team included Daniel Beavers, associate professor of statistical sciences at Wake Forest University; Barbara J. Nicklas, Ph.D., professor of gerontology and geriatrics at Wake Forest University School of Medicine; Leon Lenchik, M.D., professor of musculoskeletal imaging at Wake Forest University School of Medicine; and Ashley Weaver, Ph.D., associate professor of biomedical engineering at Wake Forest University School of Medicine; and Jason Fanning, associate professor of health and exercise science at Wake Forest University.
The study was supported by National Institute on Aging Grants R01AGO59186, K25AGO588O4, T32AGO33534, F31AGO86O1O and P30AGO21332.
Media contacts:
Myra Wright, Wake Forest University School of Medicine, mgwright@wakehealth.edu
Alicia Roberts, Wake Forest University, roberta@wfu.edu