Lexicon
Muscle Mass
Also known as Lean mass
Definition
Sarcopenia is the accelerated loss of skeletal muscle mass and function commonly, but not exclusively, associated with advancing age. [1] For the diagnosis of sarcopenia, the European Working Group on Sarcopenia in Older People recommends using the presence of both low muscle mass and low muscle function (strength or performance). [2] Sarcopenia should be differentiated from cachexia, which is characterized not only by low muscle mass but also by weight loss and anorexia. [3] Reduced muscle mass is one of the phenotypic criteria for the GLIM diagnosis of malnutrition, alongside non-volitional weight loss and low body mass index. [4]
How it works
Skeletal muscle is not only the organ related to mobility but is also recognized as a secondary secretory organ with endocrine functions influencing several systems and preserving health. [5] The age-related loss of skeletal muscle mass is not the sole contributor to the decline in physical performance, as loss of muscle strength is also a strong contributor. [6] Sarcopenia results from complex and interdependent pathophysiological mechanisms that include aging, physical inactivity, neuromuscular compromise, resistance to postprandial anabolism, insulin resistance, endocrine factors, oxidative stress, mitochondrial dysfunction, and inflammation. [3] During ageing a loss of bone and muscle mass and strength occurs, coupled with an increase in fat mass. [7]
Connected concepts
How it's measured
Muscle mass in sarcopenia studies is measured using dual-energy x-ray absorptiometry, bioelectrical impedance, or computed tomography. [8] Body composition can be assessed by a range of methods including anthropometry, densitometry, dual-energy X-ray absorptiometry, bioelectrical impedance analysis, and imaging techniques such as MRI and computed tomography that can quantify muscle and adipose tissue. [9] Radiological evaluation of sarcopenia focuses on major body composition imaging modalities such as dual-energy X-ray absorptiometry, CT, and MRI, and is limited by a lack of consensus or standardization and differing diagnostic cutoff points. [5] The AWGS 2019 algorithms begin by screening with calf circumference, defined as low at under 34 cm in men and under 33 cm in women, to facilitate earlier identification of people at risk for sarcopenia. [10]
What levels mean
Community knowledge
## Sarcopenia Risk & Assessment
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- 1.Sayer AA, Cooper R, Arai H, Cawthon PM, Ntsama Essomba MJ, Fielding RA, Grounds MD, Witham MD. Sarcopenia. Nat Rev Dis Primers · 2024
- 2.Cruz-Jentoft AJ, Baeyens JP, Bauer JM, Boirie Y, Cederholm T, Landi F, Martin FC, Michel JP. Sarcopenia: European consensus on definition and diagnosis: Report of the European Working Group on Sarcopenia in Older People. Age Ageing · 2010
- 3.Tournadre A, Vial G, Capel F, Soubrier M, Boirie Y. Sarcopenia. Joint Bone Spine · 2019
- 4.Cederholm T, Jensen GL, Correia MITD, Gonzalez MC, Fukushima R, Higashiguchi T, Baptista G, Barazzoni R. GLIM criteria for the diagnosis of malnutrition - A consensus report from the global clinical nutrition community. Clin Nutr · 2019
- 5.Tagliafico AS, Bignotti B, Torri L, Rossi F. Sarcopenia: how to measure, when and why. Radiol Med · 2022
- 6.
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