The Interplay Between Osteosarcopenia and Intrinsic Capacity: Insights and Associations With All-Cause Mortality in the Toledo Study for Healthy Aging

Background Osteosarcopenia—the coexistence of osteopenia/osteoporosis and sarcopenia—is associated with numerous adverse health outcomes, but its association with intrinsic capacity (IC) remains unknown. We aimed to explore the associations of osteosarcopenia with IC and all-cause mortality in older adults. Methods We conducted a cross-sectional analysis of IC and a prospective analysis of all-cause mortality in 1142 participants from the Toledo Study for Healthy Aging (75.1±6.0 years, 53.1% women). Participants were classified as having no musculoskeletal disorders, osteopenia/osteoporosis, sarcopenia, or osteosarcopenia (DXA- and EWGSOP2-based criteria). IC was operationalized as a composite score integrating locomotion, cognition, psychological, vitality, and sensory domains. Results Older adults with osteosarcopenia exhibited lower total IC (76.6±1.1 points) than those without musculoskeletal disorders (83.7±0.5 points; p<0.001) or with osteopenia/osteoporosis (81.3±0.3 points; p<0.001), with significant differences also found between the latter groups (p<0.001). Specifically, osteosarcopenia was associated with poorer results in the locomotion, cognition, vitality, and sensory domains (all p<0.01), but not in the psychological domain. Over a median 6.2-year follow-up, osteosarcopenia—but not osteopenia/osteoporosis—was associated with higher risk of mortality compared to those without musculoskeletal disorders [HR (95%CI)=1.96 (1.02–3.77); p=0.045]. In joint analyses with IC status (high vs. low, segregated by the median), this association was specifically observed among participants with osteosarcopenia and low IC [HR = 2.55 (1.31–4.96); p=0.004]. Conclusions Osteosarcopenia is associated with lower total IC and impairments across most IC domains. This finding is of clinical relevance, as the combination of this condition and low IC is associated with an increased mortality risk.