Bone quality response to lifestyle intervention in older adults with obesity (LIMB-Q trial): a randomised controlled trial

Lifestyle interventions for weight loss might exacerbate age-related bone loss and osteoporosis. However, there is limited knowledge about their effects on bone quality. We examined whether lifestyle intervention can preserve or enhance bone quality, despite reductions in bone mineral density. The Lifestyle Intervention to Improve Bone Quality (LIMB-Q) study was a randomised controlled trial conducted at Baylor College of Medicine and the Michael E DeBakey VA Medical Center (Houston, TX, USA) including older adults (aged 65-85 years) with obesity (BMI ≥30 kg/m2). Participants were randomly assigned to receive either an intensive lifestyle intervention (intensive lifestyle group, consisting of weight management plus exercise training) or healthy lifestyle (healthy lifestyle group, consisting of educational sessions on healthy diets). The co-primary outcomes were 12-month changes in (1) distal tibia cortical thickness, measured using high-resolution peripheral quantitative CT, and (2) hip bone strength (failure load), assessed via finite element analysis of CT scans. The primary endpoint was analysed by intention to treat (all randomly assigned patients). This trial is registered with ClinicalTrials.gov, NCT03329963 (completed). Of 138 participants assessed for eligibility in person between Nov 9, 2017, and Nov 8, 2021, 120 were included in this study (mean age 71·4 years [SD 4·6]; 63 [53%] male and 57 [47%] female). At 12 months, weight loss was greater in the intensive lifestyle group than in the healthy lifestyle group (-11·6 kg [SE 0·5] vs -1·2 kg [0·5]). No group differences were noted in the change in distal tibia cortical thickness between the intensive lifestyle group (-0·013 mm [SE 0·026]) and the healthy lifestyle group (-0·002 mm [0·025]; between-group difference 0·027 [95% CI -0·066 to 0·120], p=0·40). The change in hip failure load at 12 months did not differ between the intensive lifestyle group (13 N [SE 25]) and the healthy lifestyle group (3 N [26]; between-group difference -6.9 N [95% CI -108 to 95], p=0·89). Exercise-related adverse events in the intensive lifestyle group included a small number of musculoskeletal events (falls [one participant], neck pain [two], and foot, shoulder, back, and leg pain [one each]). Lifestyle intervention preserved bone quality in older adults with obesity during weight loss. Further research is needed to determine whether lifestyle interventions can reduce fracture risk in older adults with obesity. National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK) and US Department of Veterans Affairs.