Association of cardiorespiratory fitness with HR-pQCT bone parameters in older adults: the Study of Muscle, Mobility and Aging (SOMMA)

UNLABELLED: Higher cardiorespiratory fitness may be associated with better bone health in older age, though this has not been investigated using state-of-the-science VO₂peak and HR-pQCT bone density, strength, and microarchitecture measures. We found that higher VO₂peak associated with higher bone strength in men, but not women, which may inform fracture prevention interventions. INTRODUCTION: Maintaining cardiorespiratory fitness among older adults holds potential benefits for bone health, though this association has not been investigated using gold-standard measures of VO₂peak and state-of-the-science measures of bone density, strength, and microarchitecture. METHODS: Participants included 123 men (age 76.2 ± 4.4 years, 93% White) and 188 women (age 76.1 ± 4.7 years, 87% White) in the Study of Muscle, Mobility and Aging (SOMMA). Absolute peak oxygen consumption (VO₂peak) was measured from treadmill cardiopulmonary exercise testing using a modified Balke protocol at the baseline visit. High-resolution peripheral quantitative computed tomography (HR-pQCT) and dual-energy X-ray absorptiometry (DXA) scans were collected after the first annual follow-up visit (mean follow-up 1.2 ± 0.1 years) to assess radial and tibial bone microarchitecture and strength and hip areal bone mineral density (BMD), respectively. VO₂peak and bone parameters were standardized within sex and analyses were stratified by sex. Linear regression models adjusted for age, race, weight, alcohol consumption, smoking, physical activity (wrist-worn accelerometry), multimorbidity index, arthritis, hypertension, and limb length (HR-pQCT parameters) or height (DXA parameters). RESULTS: In men, higher VO₂peak (per SD) was associated with higher tibial (standardized [std] β = 0.26, p = 0.03) and radial (std β = 0.36, p = 0.007) failure load, but not with DXA or other HR-pQCT bone parameters. No significant associations were found for women. CONCLUSIONS: Associations of VO₂peak with bone strength found in older men suggest VO₂peak is associated with bone parameters in a sex-specific manner and mechanisms for these sex differences should be explored. Interventions aimed at increasing cardiorespiratory fitness should be evaluated for potential benefit to bone health among older men.