Weighted Vest Use or Resistance Exercise to Offset Weight Loss-Associated Bone Loss in Older Adults: A Randomized Clinical Trial.

Importance: Weight loss (WL) in older adults is associated with bone loss, increasing the risk of fracture. Because skeletal tissue is responsive to mechanical stress, replacing lost weight externally may be an innovative way to minimize WL-associated bone loss in this population. Objective: To examine the effect of 12 months of weighted vest use during WL on indicators of bone health compared with WL alone and WL plus resistance training (RT). Design, Setting, and Participants: This single-blind, 12-month randomized clinical trial of older adults living with obesity was conducted at an academic medical center from September 1, 2019, to April 30, 2024. Interventions: WL (caloric restriction targeting 10% WL with adequate calcium, vitamin D, and protein), WL plus weighted vest (WL+VEST; 8 h/d, weight replacement titrated up to 10% total WL), or WL plus progressive RT (WL+RT; supervised 3 sessions weekly). Main Outcomes and Measures: Main outcomes included 12-month change in computed tomography-acquired trabecular volumetric bone mineral density (vBMD) and dual-energy X-ray absorptiometry-acquired areal bone mineral density (aBMD) of the total hip. Secondary outcomes included change in additional computed tomography- and dual-energy X-ray absorptiometry-acquired measures of musculoskeletal health and bone turnover biomarkers. Results: A total of 150 older (mean [SD] age, 66.4 [4.6] years) adults (112 [74.7%] women) living with obesity (mean [SD] body mass index, 33.6 [3.3]) were randomized (50 to WL, 50 to WL+VEST, and 50 to WL+RT), with 133 (88.7%) completing the trial. Similar significant WL, ranging from 9.0% to 11.2%, was achieved in all groups. During 12 months, mean (SD) self-reported weighted vest wear time was 7.1 (1.5) h/d, with 78.0% (29.9%) of lost weight replaced in the vest; participants randomized to the WL+RT group attended a mean (SD) of 71.4% (19.1%) of sessions. A significant decrease in total hip trabecular vBMD was observed at 12 months in all treatment groups (ranging from -1.2% to -1.9%), with no difference between the WL+VEST and WL groups (estimated treatment difference, +0.91 mg/cm3; 97.5% CI, -0.27 to 2.09 mg/cm3; P = .13) and noninferiority of WL+VEST compared with WL+RT (estimated treatment difference, +0.29 mg/cm3; 98.75% lower bound, -1.05 mg/cm3). Similar effects were observed for total hip aBMD. Conclusions and Relevance: In this 12-month randomized clinical trial, neither weighted vest use nor progressive RT was able to mitigate WL-associated bone loss at the hip in older adults living with obesity. This study highlights the need for alternative or adjunctive strategies to prevent bone loss in older adults experiencing WL because exercise may be insufficient on its own. Trial Registration: ClinicalTrials.gov Identifier: NCT04076618.