Abstract / Summary
Abstract Background Osteosarcopenia is a clinically relevant geriatric phenotype characterized by the coexistence of impaired bone health, reduced muscle mass or function, and adiposity-related metabolic dysfunction. Body mass index does not adequately reflect adipose tissue distribution, muscle impairment, or skeletal vulnerability in older adults with sarcopenic obesity. This study investigated whether body shape–based anthropometric indices reflecting central adiposity are associated with osteosarcopenia in this population. Methods This retrospective cross-sectional study included 203 older adults aged ≥ 65 years with sarcopenic obesity evaluated at a tertiary geriatric outpatient clinic. Sarcopenic obesity was defined according to ESPEN/EASO criteria using bioelectrical impedance analysis and functional assessments. Osteoporosis was diagnosed by dual-energy X-ray absorptiometry using a T-score ≤ − 2.5. Osteosarcopenia was defined as the coexistence of sarcopenic obesity and osteoporosis. Associations of A Body Shape Index (ABSI), Body Roundness Index (BRI), waist-to-height ratio (WHtR), and weight-adjusted waist index (WWI) with osteosarcopenia were evaluated using receiver operating characteristic (ROC) analysis and multivariable logistic regression. Results Among 203 older adults with sarcopenic obesity, 23 (11.3%) had osteosarcopenia. Individuals with osteosarcopenia were older (77 vs. 71 years, p = 0.001), had lower handgrip strength (13.4 vs. 20.0 kg, p < 0.001), and had higher ABSI (25.30 vs. 21.67, p = 0.001), BRI (9.69 vs. 8.13, p < 0.001), and WWI (12.96 vs. 12.13, p < 0.001). ABSI showed the highest discriminatory performance in ROC analysis (AUC 0.821). In multivariable logistic regression models, ABSI (OR 1.197, 95% CI 1.057–1.357, p = 0.005), BRI (OR 1.620, 95% CI 1.221–2.150, p = 0.001), and WWI (OR 3.749, 95% CI 1.720–8.169, p = 0.001) remained independently associated with osteosarcopenia. Conclusions Body shape–based anthropometric indices were independently associated with osteosarcopenia in older adults with sarcopenic obesity. These readily obtainable measures may provide complementary information for risk stratification of musculoskeletal vulnerability beyond conventional obesity assessment. However, they should be interpreted as risk-stratification markers rather than standalone diagnostic measures.