Associations of body composition trajectories with bone mineral density, muscle function, falls and fractures in older men: The Concord Health and Ageing in Men Project.

Abstract

Background Weight loss increases fracture risk in older adults. We aimed to determine associations of 2-year body composition trajectories with subsequent falls and fractures in older men. Methods We measured appendicular lean mass (ALM) and total fat mass (FM) by dual-energy X-ray absorptiometry at baseline and Year 2 in 1,326 community-dwelling men aged ≥70 and older. Body composition trajectories were determined from residuals of a linear regression of change in ALM on change in FM (higher values indicate maintenance of ALM over FM), and a categorical variable for change in ALM and FM (did not lose [≥−5% change] versus lost [<−5% change]). Bone mineral density (BMD), hand grip strength, and gait speed were assessed at Years 2 and 5. After Year 2, incident fractures (confirmed by radiographical reports) and falls were recorded for 6.8 years. Results Compared with men who did not lose ALM or FM, men who did not lose ALM but lost FM, and men who lost both ALM and FM, had reduced falls (−24% and −34%, respectively; both p < .05). Men who lost ALM but did not lose FM had increased falls (incidence rate ratio = 1.73; 95% CI 1.37–2.18). ALM/FM change residuals were associated with improved lumbar spine BMD (B = 0.007; 95% CI 0.002–0.012 g/cm2 per SD increase) and gait speed (0.015; 0.001–0.029 m/s), and reduced hip fractures (hazard ratio = 0.68; 95% CI 0.47–0.99). Conclusions Fracture risk may be increased in older men who lose higher ALM relative to FM. Weight loss interventions for obese older men should target maintenance of lean mass.