Sarcopenia Definition:
What is Sarcopenia?
Sarcopenia is a health condition characterized by the loss of skeletal muscle mass and function, particularly impacting muscle strength and gait speed. This phenomenon, often associated with aging, is a primary cause of muscle wasting, affecting millions of elderly individuals as well as patients suffering from cachexia and malnutrition. Notably, muscle atrophy can occur independently from aging and diseases, developing as a result of muscle disuse.
In medical science, there’s an ongoing proposition to unify the concepts of muscle wasting, sarcopenia, frailty, and cachexia by disease etiology and progression for a clearer classification and common language. Patients with muscle atrophy exhibit decreased muscle strength, leading to reduced quality of life due to decreased activity and increased exercise intolerance.
Despite numerous studies, our understanding of muscle wasting development and the involved pathways remains limited, warranting further research. Although several attempts have been made by researchers and pharmaceutical companies to find therapies for muscle atrophy, including cachexia and sarcopenia, no definitive solution has been established to date.
Sarcopenia was first characterized by the slow and progressive loss of muscle mass that is associated with ageing in the absence of any underlying disease or condition. Subsequently, it was recognized that the key element was a loss of muscle strength (dynapenia) rather than a loss of muscle mass. This has led to a change in the definition to include strength (grip strength) or function (walking speed or distance).
Based on this concept, a number of societies around the world have provided revised definitions (Table below). These definitions have to some extent de-emphasized the importance of ageing, recognizing that sarcopenia has a variety of causes in addition to the physiological effects of aging. The increased interest in this subject is clearly seen by the number of publications published in the last few years compared to previously.
The prevalence from 15% at 65 years to 50% at 80 years in humans, with normal ageing associated with a 1–2% muscle loss beyond the age of 50 years.
Furthermore, the rapidly expanding aging population will only exacerbate the health problems associated with sarcopenia, which directly leads to increased hospitalizations and disability, due in part, by contributing to falls, fractures, and frailty in the elderly.
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Recognizing Sarcopenia Symptoms and Signs
Sarcopenia was initially characterized by a slow, progressive loss of muscle mass associated with aging, without any underlying disease or condition. However, it was later recognized that the loss of muscle strength, or dynapenia, was a more crucial factor than the loss of muscle mass. This realization led to a redefinition of sarcopenia to include strength (such as grip strength) or function (like walking speed or distance). In addition to aging, sarcopenia can be caused by various other factors, as recognized in the revised definitions provided by multiple societies worldwide.
Addressing Sarcopenia Treatment Approaches and Advance
While the search for effective treatments for sarcopenia is ongoing, current strategies focus on lifestyle modifications, including physical exercise and nutritional optimization. Certain pharmacological interventions are also being explored to counter muscle loss and improve physical function.
The prevalence of sarcopenia increases from 15% at 65 years to 50% at 80 years in humans. Normal aging is associated with a 1–2% muscle loss beyond the age of 50 years. The rapidly expanding aging population will likely exacerbate the health issues related to sarcopenia, leading to increased hospitalizations and disability, often as a result of falls, fractures, and frailty in the elderly.
References
Rosenberg IH, Roubenoff R. Stalking sarcopenia. Ann Intern Med 1995;123:727-8.
Cruz-Jentoft AJ, Baeyens JP, Bauer JM, Boirie Y, Cederholm T, Landi F, et al. Sarcopenia: European consensus on definition and diagnosis: Report of the European Working Group on Sarcopenia in Older People. Age Ageing 2010; 39: 412–423.
Kim TN, Choi KM. Sarcopenia: definition, epidemiology, and pathophysiology. J Bone Metab 2013; 20: 1–10.
Morley JE, Anker SD, Haehling von S. Prevalence, incidence, and clinical impact of sarcopenia: facts, numbers, and epidemiology-update 2014. J Cachexia Sarcopenia Muscle 2014; 5: 253–259.
