Osteosarcopenia, bone-muscle interactions, and Frailty risk: A Prospective Cohort Study of Community- Dwelling Older Adults

Background Osteosarcopenia, defined as the coexistence of osteopenia/osteoporosis and sarcopenia, may influence frailty risk in older adults. However, the longitudinal association between osteosarcopenia and its components with frailty remains unclear. This study aimed to address this. Methods Data from a prospective cohort study of community-dwelling adults in Australia. Frailty was defined by the presence of three or more components based on Fried criteria: exhaustion, slow gait speed, low grip strength, unintentional weight loss, and low physical activity. Osteosarcopenia was defined by osteopenia/osteoporosis (WHO criteria) and sarcopenia (European Working Group on Sarcopenia in Older People [EWGSOP2] and Sarcopenia Definition and Outcome consortium [SDOC]). Multivariable logistic regression models evaluated the associations between osteosarcopenia or its components with frailty. Results Of 301 participants enrolled, 151 (mean age: 65.1 years, 59.6% women) completed a follow-up (median: 4.5 years). Osteosarcopenia was associated with frailty risk irrespective of the definition used: EWGSOP2: OR = 8.13, 95% CI 1.61–41.10; SDOC OR = 8.0, 95% CI 1.42–45.06). Among its components, low grip strength (OR = 0.92, 95% CI 0.84–1.00) and slow gait speed (OR = 0.67, 95% CI 0.53–0.85) were independently associated with frailty; bone mineral density/lean mass were not. An interaction between bone and muscle health and frailty risk was observed (p < 0.011), whereby higher values of grip strength were protective against frailty when bone density was lower (the opposite was also true). Conclusion In this prospective cohort study, osteosarcopenia increased the risk of frailty. Our interaction analysis suggests therapies targeting bone density and grip strength may mitigate against frailty.