Differences in Muscle Quantity and Quality by HIV Serostatus and Sex.

OBJECTIVE: People with HIV (PWH) experience greater declines in both muscle function and muscle mass with aging. Whether changes in muscle quality and quantity with aging differ between men and women with HIV and the implications on muscle function are not established. DESIGN: In coordinated substudies of the Multicenter AIDS Cohort Study and Women's Interagency HIV Study, participants completed physical function and falls assessments; total trunk/thigh density, inversely related to fatty infiltration, and area were quantified from computed tomography (CT) scans. METHODS: Generalized linear models were used to explore variables affecting density/area, and associations between area/density and physical function and falls. RESULTS: CT scans were available on 387 men (198 PWH) and 184 women (118 PWH). HIV serostatus was associated with greater lateralis, paraspinal, and hamstring area, but lower psoas area and density. Older age and female sex were associated with smaller trunk muscle area and lower density. Both lower muscle area and muscle density were associated with several measures of impaired physical function. The odds of falling were lower with greater hamstring density, but not associated with other measurers of muscle area or density. CONCLUSIONS: In summary, older adults with HIV appear to have smaller and less dense (fattier) psoas, a key component in truncal stability and hip flexion that could have implications on physical function. The longitudinal associations of muscle area and density with physical function require careful investigation, with a particular focus on characteristics and interventions that can preserve muscle area, density, and function over time.