Lifestyle Intervention and Bone Quality in Older Adults with Obesity

Weight loss in older adults with obesity is often prescribed to help improve cardiometabolic health, but it can often accelerate loss of bone and muscle, raising fracture risk. The Lifestyle Intervention to Improve Bone Quality (LIMB-Q) trial, performed at Baylor College of Medicine and the Michael E. DeBakey VA Medical Center, set out to study this issue and published their results in the September 2025 issue of The Lancet Healthy Longevity.

The trial examined whether a structured program combining calorie restriction with exercise could achieve meaningful weight loss without compromising bone quality.

Study Designed for Precision Bone Assessment

LIMB-Q was a single-center, assessor-masked, randomized controlled trial enrolling 120 adults aged 65 to 85 years with obesity (mean age, 71 years; BMI ≥30 kg/m²). Participants were randomized 1:1 to either an intensive lifestyle intervention, consisting of dietary weight management plus three times-weekly aerobic, resistance, and balance training, or a healthy lifestyle control, which offered monthly nutrition education without weight loss guidance.

The investigators used advanced imaging to capture the multifaceted concept of bone quality, incorporating structural, microarchitectural, and material properties rather than relying solely on bone mineral density (BMD).

Co-primary endpoints were 12-month changes in distal tibia cortical thickness, measured by high-resolution peripheral quantitative CT (HR-pQCT), and hip bone strength, assessed by finite element analysis (FEA) of quantitative CT scans. Secondary measures included trabecular bone score (TBS), bone material strength index (BMSi), and circulating bone and metabolic biomarkers.

Key Findings: Weight Loss without Skeletal Compromise

At 12 months, participants in the intensive lifestyle arm achieved a mean weight loss of 11.6 kg compared with 1.2 kg in controls. Despite this, the co-primary outcomes, tibial cortical thickness and hip failure load, did not differ significantly between groups, indicating that bone structure and mechanical strength were preserved.

More nuanced markers suggested an adaptive skeletal response rather than deterioration in the intervention group:

• Spine strength improved by 5% while remaining unchanged in controls (between-group difference, −139 N; 95% CI, −229 to −48).
• Trabecular bone score increased by 3%, while it was stable in the control group.
• Bone material strength (BMSi) rose by approximately 5%.
• Factor-of-risk values—the ratio of applied load to bone strength—declined at both hip and spine, suggesting reduced mechanical vulnerability despite lower BMD.

Although total hip area BMD decreased by 2%, volumetric analyses and structural metrics suggested this reduction did not translate into weaker bone. The modest BMD loss likely reflected mechanical unloading from reduced body mass rather than intrinsic skeletal fragility.

The benefits extended beyond bone. The intensive lifestyle intervention improved muscle quality, reduced visceral fat, and enhanced physical performance measures, including the 6-minute walk, knee extensor strength, and Physical Performance Test. Circulating inflammatory markers (IL-6, hs-CRP) and leptin declined, while IGF-1 increased, collectively pointing toward a more anabolic, less inflammatory milieu conducive to bone maintenance.

Adherence rates were high, with over 85 percent attendance for both dietary and exercise sessions. Exercise-related adverse events were infrequent, including musculoskeletal pain and one fall.

Limitations and Future Directions

LIMB-Q was not powered to assess fracture incidence or sex-specific differences, and its one-year duration limits inference about long-term skeletal trajectories. Participants were community-dwelling and physically able to exercise, so generalizability to frailer populations is uncertain.

Further studies should examine whether the observed gains in bone quality metrics translate into fewer fractures over time, and whether combining lifestyle intervention with pharmacologic antiresorptive or anabolic agents might yield additive benefit.

Clinical Takeaway

Lifestyle modification remains the foundation of obesity management in older adults. The LIMB-Q trial demonstrates that when appropriately designed, such interventions can deliver robust metabolic benefits while preserving, and potentially enhancing, bone quality.

Reference
Gregori G, Mediwala S, Liebschner M, et al. Bone quality response to lifestyle intervention in older adults with obesity (LIMB-Q trial): a randomized controlled trial. Lancet Healthy Longev. Published online September 30, 2026. doi:10.1016/j.lanhl.2025.100761