Defining sarcopenia in terms of skeletal health.

Abstract

Various sarcopenia definitions and cutoff points result in mixed skeletal health results. Here, we aimed to determine a suitable definition and elucidate the cutoff values of sarcopenic indices for identifying fracture risk in a community-dwelling Korean cohort. In an Ansung cohort study (2009-2010), we included 1201 men aged > 50years and 1627 postmenopausal women with a median age of 64years. Body composition and bone mineral density were derived on dual-energy X-ray absorptiometry. Grip strength was measured using a hand dynamometer. Fragility fractures included the history of osteoporotic fractures using self-reported questionnaires. Among appendicular lean mass (ALM)/body mass index (BMI), ALM/height2, and ALM/weight, ALM/height2 for men and ALM/BMI for women significantly predicted fragility fractures. On receiver operating characteristic curve analysis, the cutoff values of ALM/height2 in men and ALM/BMI in women were 7.69kg/m2, and 0.57, respectively. The optimal grip strength values were 31kg in men and 19kg in women. The odds ratios of low ALM/height2 (95% confidence interval) and weak grip strength for fragility fracture were 1.95 (1.03-3.68) and 2.05 (1.01-4.18), respectively, in men after covariate adjustment. The combination of low ALM/height2 and weak grip strength increased fragility fractures 2.16-fold in men. Only the combination of low ALM/BMI and grip strength increased the fracture risk by 1.76-fold in women. In men, low ALM/height2 or grip strength played a role in fragility fractures. In women, only the combination of low ALM/BMI and grip strength had discriminatory power for fragility fractures.