Definitions of Sarcopenia Across the World

Abstract

Aging is accompanied by the progressive decline of muscle mass and strength; a condition called sarcopenia. During the past three decades, the number of publications with the Medical Subject Heading (MeSH) term “sarcopenia” has been steadily increasing. Several operational definitions of sarcopenia have been proposed over the years by different expert groups and task forces worldwide. The first operational definitions were primarily focused on the evalutation of low muscle mass. Subsequently, as soon as the strong predictive role for negative outcomes of muscle strength emerged, the defining algorithms of sarcopenia evolved to privilege a bidimensional construct to include both the quantity and quality of the muscle. Interestingly, sarcopenia is today a formal nosological condition, having received a specific code in the International Classification of Diseases (ICD-10).

Unfortunately, controversy still exists about the operational definition to universally adopt for defining sarcopenia. Different criteria and cut-points have been proposed in the literature. Such heterogeneity is undoubtedly impacting the wide adoption of the construct in the clinical setting but may find a strong rationale in the different body composition profiles existing across populations. In this chapter, we present how the definitions of sarcopenia proposed by the different consensus papers and international recommendations have been adapted and applied across countries and regions.