Defining sarcopenia in terms of skeletal health

Among several sarcopenic indices, height-adjusted appendicular lean mass (ALM) in men and BMI-adjusted ALM in women are associated with fragility fracture. Handgrip strength is the risk factor for fragility fracture.

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 > 50 years and 1627 postmenopausal women with a median age of 64 years. 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 7.69 kg/m², and 0.57, respectively. The optimal grip strength values were 31 kg in men and 19 kg 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.