Osteosarcopenia, the coexistence of bone and muscle loss, is common in older adults, but its definition lacks international consensus. This cross-sectional study (n = 1199 post-menopausal women) aimed to determine the association between osteosarcopenia and fragility fractures and to investigate the impact of the definition of the "osteo" component. Bone mineral density and bone microarchitecture were measured by dual-energy X-ray absorptiometry and the trabecular bone score (TBS), respectively. The "osteo" component of osteosarcopenia was classified as osteoporosis (T-score ≤ -2.5 SD), osteopenia/osteoporosis (T-score < -1 SD), and high-fracture-risk osteopenia (-2.5 SD < T-score < -1 SD)/osteoporosis (T-score ≤ -2.5 SD). The Fracture Risk Assessment Tool was used to identify high-fracture-risk osteopenia. Altogether, 30.3%, 32.2%, 14.4%, and 23.1% of participants had osteosarcopenia, osteoporosis alone, sarcopenia alone, and neither condition, respectively. The odds ratios between osteosarcopenia and fragility fractures were 3.70 (95% CI: 1.94-7.04) for osteosarcopenia, 2.48 (95% CI: 1.30-4.71) for osteoporosis alone, and 1.87 (95% CI: 0.84-4.14) for sarcopenia alone. Women with osteosarcopenia also had lower TBS, indicating worse bone microarchitecture. In conclusion, women with osteosarcopenia were more likely to have previously sustained a fracture compared to those without osteosarcopenia, with sarcopenia alone, and with osteoporosis alone. The relationship between osteosarcopenia and fracture risk may be best identified when considering high-fracture-risk osteopenia and osteoporosis.
Keywords: CHOS study; fragility fracture; osteoporosis; osteosarcopenia; trabecular bone score.