Sarcopenia (ICD-10-CM code M62.84[1]) is a type of muscle loss that occurs with aging and/or immobility. It is characterized by the degenerative loss of skeletal muscle mass, quality, and strength. The rate of muscle loss is dependent on exercise level, co-morbidities, nutrition and other factors. The muscle loss is related to changes in muscle synthesis signalling pathways. It is distinct from cachexia, in which muscle is degraded through cytokine-mediated degradation, although the two conditions may co-exist. Sarcopenia is considered a component of frailty syndrome.[2] Sarcopenia can lead to reduced quality of life, falls, fracture, and disability.[3][4]
Sarcopenia is a factor in changing body composition. When associated with aging populations, certain muscle regions are expected to be affected first, specifically the anterior thigh and abdominal muscles.[3][5] In population studies, body mass index (BMI) is seen to decrease in aging populations while bioelectrical impedance analysis (BIA) shows body fat proportion rising.[6]
A new sarcopenia related condition is the Steatosarcopenia proposed by the Steatosarcopenia & Sarcopenia Brazilian Study Group. This condition is characterized by the loss of mass or skeletal muscle strength and performance associated with the excessive deposition of ectopic reserve fat in muscle tissue, in the same individual, not necessarily related to [7]excess fat total body mass. Steatosarcopenia: A New Terminology for Clinical Conditions Related to Body Composition Classification.
^ abAta AM, Kara M, Kaymak B, Özçakar L (October 2020). "Sarcopenia Is Not "Love": You Have to Look Where You Lost it!". American Journal of Physical Medicine & Rehabilitation. 99 (10): e119–e120. doi:10.1097/PHM.0000000000001391. PMID32084033. S2CID211245329.
^Ata AM, Kara M, Kaymak B, Gürçay E, Çakır B, Ünlü H, et al. (2019). "Regional and total muscle mass, muscle strength and physical performance: The potential use of ultrasound imaging for sarcopenia". Archives of Gerontology and Geriatrics. 83: 55–60. doi:10.1016/j.archger.2019.03.014. PMID30953961. S2CID96463073.