Jump Power Predicts Fracture Risk in Older Adults Independent of Sarcopenia and FRAX

Low countermovement jump power is associated with prevalent fracture, osteoporosis, and sarcopenia in older adults. However, whether jump power predicts incident fracture risk remains uninvestigated. Data of 1366 older adults in a prospective community cohort were analyzed. Jump power was measured using a computerized ground force plate system. Fracture events were ascertained by follow-up interview and linkage to the national claim database (median follow-up 6.4 years). Participants were divided into normal and low jump power groups using a predetermined threshold (women <19.0 W/kg; men <23.8 W/kg; or unable to jump). Among the study participants (mean age 71.6 years, women 66.3%), low jump power was associated with a higher risk of fracture (hazard ratio [HR] = 2.16 versus normal jump power, p < 0.001), which remained robust (adjusted HR = 1.45, p = 0.035) after adjustment for fracture risk assessment tool (FRAX) major osteoporotic fracture (MOF) probability with bone mineral density (BMD) and Asian Working Group for Sarcopenia (AWGS) 2019 sarcopenia definition. In the AWGS no sarcopenia group, participants with low jump power had a significantly higher risk of fracture than those with normal jump power (12.5% versus 6.7%; HR = 1.93, p = 0.013), comparable to that of possible sarcopenia without low jump power (12.0%). Possible sarcopenia group with low jump power had a similar risk of fracture (19.3%) to sarcopenia group (20.8%). When the definition of sarcopenia was modified with jump power measurement (step-up approach: no sarcopenia to possible sarcopenia; possible sarcopenia to sarcopenia when low jump power present), jump power-modified sarcopenia improved sensitivity (18%-39.3%) to classify individuals who sustained MOF during follow-up to high risk compared with AWGS 2019 sarcopenia, while maintaining positive predictive value (22.3%-20.6%). In summary, jump power predicted fracture risk in community-dwelling older adults independently of sarcopenia and FRAX MOF probabilities, suggesting potential contribution of complex motor function measurement in fracture risk assessment. © 2023 American Society for Bone and Mineral Research (ASBMR).