Abstract
Osteosarcopenia is the coexistence of low bone mass and sarcopenia. In older women, its prevalence is not well described, and it is unknown if sarcopenia is additive to low bone mass for fracture and mortality risk. The study investigated prevalence of osteosarcopenia and if osteosarcopenia is associated with higher fracture and mortality risk than low bone mass alone in older community-dwelling women. The longitudinal, population-based OPRA Cohort (n = 1044), all aged 75 at inclusion, followed for 10 years. Using WHO and EWGSOP2 definitions for low bone mass (T-score < -1.0 femoral neck) and sarcopenia (knee strength; appendicular lean muscle mass) women were categorized (1) Normal, (2) Low bone mass (LBM), and 3) Osteosarcopenia (probable; confirmed). Risk of hip, major osteoporotic fracture, and mortality were estimated. Osteosarcopenia(confirmed) prevalence increased from age 75 to 80 and 85 from 3.0% (29/970) to 4.9% (32/656) to 9.2% (33/358) but prevalence is potentially 2-4 times higher (11.8%, 13.4%, 20.3%) based on osteosarcopenia(probable). Having osteosarcopenia(probable) significantly increased 10-year risk of hip fracture (HR(adj) 2.67 [1.34-5.32]), major osteoporotic fracture (HR(adj) 2.04 [1.27-3.27]), and mortality (HR(adj) 1.91 [1.21-3.04]). In contrast, LBM increased osteoporotic fracture risk (HR(adj) 2.08 [1.46-2.97], but not hip fracture (HR(adj) 1.62 [0.92-2.85]) or mortality (HR(adj) 0.94 [0.64-1.38]). Median time-to-hip fracture was 7.6 years (normal), 6.0 years (LBM), and 5.7 years (osteosarcopenia(probable)). Prevalence of confirmed osteosarcopenia is almost 10% at age 85. Probable osteosarcopenia significantly increased risk of hip and major osteoporotic fractures and mortality more so than low bone mass alone.