Purpose of review: To summarize the latest advances and caveats in defining sarcopenia and discuss the implications of the most recent worldwide initiatives which are trying to harmonize the definition.
Recent findings: The evolution over time of the definitions of sarcopenia is discussed, with a focus on the European Working Group on Sarcopenia in Older People 2 (EWGSOP2) definition and the Sarcopenia Definitions and Outcomes Consortium (SDOC) conference. The EWGSOP2 and the SDOC agree on the overall concept of sarcopenia, which involves both impaired function (low muscle strength) and structural damage (low muscle mass/quality). However, physical performance is considered as a diagnostic criterion (EWGSOP), a severity grading assessment (EWGSOP2) or an outcome (SDOC) pending on the definition used. Muscle strength has been recognized as the best predictor of health outcomes. Muscle mass alone, as part of the definition of cachexia, sarcopenia and malnutrition, is a nondefining parameter. Furthermore, there is a lack of precision in measurement techniques and variability of the cut-off points in defining it.
Summary: We discuss the relationship of sarcopenia with cachexia, malnutrition and frailty, and the areas that are hampering agreement. We summarize key scientific evidence, consider future study of this nutrition-related disease and raise concern about the need for a universal definition of sarcopenia.