What is sarcopenia?

 

Sarcopenia is a disease associated with the aging process. Loss of muscle mass and strength, which in turn affects balance, gait and overall ability to perform tasks of daily living, are hallmark signs of this disease. 

Scientists have long believed muscle loss and others signs associated with aging are an inevitable process. However, researchers are looking for ways in which we can slow the aging process, specifically in relation to loss of muscle mass and strength.

Loss of muscle mass, strength and function

SarcopeniaNormal muscle mass on left, muscle wasting on right

Sarcopenia is, in its most literal sense, the loss of muscle mass, strength and function related to aging.  We are now discovering this loss is a complex and multifaceted process.  Most commonly seen in inactive people, sarcopenia also affects those who remain physically active throughout their lives1.

This indicates although a sedentary lifestyle contributes to this disease, it's not the only factor.

 

In addition, as we age:

  • hormone levels change
  • protein requirements alter
  • motor neurons die
  • and we tend to become more sedentary 

Prevention and treatment

These factors in combination are what are thought to cause sarcopenia. Scientists are searching for ways to treat and prevent progression of this disease process by developing treatments targeting individual factors.

In a review of literature, worsening sarcopenia followed trends in losses of muscle strength as well as impairment of daily functioning2. In one study, the prevalence of sarcopenia increased dramatically with age from 4 % of men and 3 % of women aged 70-75 to 16 % of men and 13 % of women aged 85 or older3.

Fig. 1 Life course changes in muscle mass and strength. Note environmental changes can lower the disability threshold2.

 

More importantly, when sarcopenia is coupled with other diseases associated with aging, its affects can be even more pronounced. Loss of muscle mass and strength is a significant risk factor for disability in the aging population4. When patients suffer from both sarcopenia and osteoporosis, the risk of falling and subsequent fracture incidence is higher5. Therefore, treating sarcopenia will in turn help to lessen its burden on co-existing diseases.

 

References

1. Brink W (2007) Preventing Sarcopenia. LifeExtension Magazine
2. Mithal A, Bonjour J-P, Boonen S, Burckhardt P, Degens H, El Hajj Fuleihan G, Josse R, Lips P, Morales Torres J, Rizzoli R, Yoshimura N, Wahl D.A., Cooper C, Dawson-Hughes B(2011) Impact of nutrition on muscle strength and performance in older adults. Osteoporosis International (in press)
3. Castillo EM, Goodman-Gruen D, Kritz-Silverstein D, Morton DJ, Wingard DL, Barrett-Connor E (2003) Sarcopenia in elderly men and women - The Rancho Bernardo Study. Am J Prev Med 25: 226-231
4. Volpi, E, Nazemi R, Fujita S, (2004) Muscle tissue changes with aging. Curr Opin Nutr Metab Care July, 7(4):405-410
5. Sarcopenia: European consensus on definition and diagnosis, Report of the European Working Group on Sarcopenia in Older People," Age and Ageing Advance Access originally published online on April 13, 2010, Age and Ageing 2010 39(4):412-423