What Is Sarcopenia?
Muscle Disease that Leads to a Loss of Mobility & Independence
Sarcopenia is a progressive loss of muscle mass and/or quality characterized by a decline in muscle strength and/or physical performance. It is a condition commonly found in the geriatric population and can be compounded by lifestyle issues, such as suboptimal diet or lack of exercise.
A decline in muscle strength or physical performance caused by decreased muscle mass and/or quality brings serious risks on the patients’ quality of life (QOL) and mortality. If it reaches a certain level, the patients can lose their mobility, which leads to a loss of independence. It is known that a disability risk in sarcopenia patients is 1.5 to 4.6 times higher than that of the same healthy age groups. Further, muscle function in patients with sarcopenia is also known as a predictor of the mortality.
In a narrow sense, sarcopenia refers to a syndrome of muscle mass and/or quality loss, most commonly seen in patients over the age of 65, and possibly beginning in their 40s. In a broader sense, it refers to muscle loss for any reason, not limited to aging. In the case of secondary sarcopenia, clinical management should include the treatment or improvement of prevailing symptoms.
Sarcopenia is a progressive condition resulting from an imbalance of muscle metabolism or a loss of metabolic homeostasis in skeletal muscle. During aging and/or pathological progress of sarcopenia, it is known that patients are losing not only flexibility in their diet and exercise capacity but also the sensitivity and adaptation to environmental stimuli, such as exercise or nutrition. Therefore, it is expected to be clinically managed at an earlier stage.
Acceleration of Aging -Clinically Manageable
Sarcopenia can lead to a loss of muscle function, mobility and independence; it essentially mimics and accelerates the changes to muscle occurring during the aging process. In particular, it predisposes older people to parallel and overlapping risks of a loss of mobility and independence as a result of acceleration of a decline in muscle function. When this decline reaches a threshold level (for any given age group), medical evaluation is indicated to determine whether sarcopenia is present.
So sarcopenia has not been recognized as a clinically manageable condition, but as an unavoidable part of aging. Based on such traditional recognition, patients have had no other option but to live with anxiety about this progressive condition and endure a decreased QOL associated with critical risks for loss of mobility and independence and increased mortality rates. As a result of recent studies and academic debates, sarcopenia has been re-categorized as an abnormal condition that can be clinically managed through a protocol which includes modification of lifestyle and nutritional support.
High Prevalence in the U.S. Senior Population
The European Sarcopenia Working Group (ESWG) estimated the prevalence of 5-13% in people 61-79 years of age, and 11-50% in those 80 years of age and above. According to a cohort study by Iannuzzi-Sucich et al., the estimated prevalence of sarcopenia in the U.S. is 22.6% in women 64 years of age and above, 31.0% in women 80 years of age and above, 26.8% in men 64 years of age and above, and 52.9% in men 80 years of age and above. Those numbers are similar to those of diabetes in seniors (diagnosed and undiagnosed: 25.9% in ADA’s 2012 statistics) in the U.S.
Sarcopenia is also considerable in terms of economic burden to the patients and public healthcare expenditures. The excess medical costs directly associated with sarcopenia are annually $860 in men and $933 in women. Based on the excessive direct costs per patient, Janssen et al. estimated that direct healthcare costs attributed to sarcopenia in the U.S. in 2000 were $18.5 billion. It represented 1.5% of total healthcare expenditures for that year.
Kalache A, Kickbusch I. A global strategy for healthy ageing. WORLD HEALTH. 1997 Jul-Aug; 50(4): 4-5.