Sarcopenia: the silent muscle-wasting disease

AN estimated one in five Australians over the age of 65 years are living with the muscle-wasting disease called sarcopenia. Sarcopenia causes muscle impairment or failure and is defined as a progressive loss of skeletal muscle mass, strength and function associated with ageing that can significantly affect an individual’s quality of life and capacity to live independently.

The importance of maintaining our skeletal muscle for health is largely underappreciated. Skeletal muscle is the largest tissue in the body. It is vital for locomotion, posture and breathing but also has an important metabolic role. Muscle influences energy and protein metabolism throughout the body and is the primary storage site for glucose uptake.

Sarcopenia or muscle loss is linked to almost all common chronic diseases. This ranges from falls, fractures and frailty to type 2 diabetes, cardiovascular disease, and dementia. For some people, especially older adults and those who are hospitalised or bedridden, we know that if a certain amount of muscle is lost, their immune response can be compromised, resulting in an increased risk of infection and disease. The evidence also reveals that muscle loss reduces life expectancy.

Despite its health impact, sarcopenia is a relatively new concept in the medical sphere, only being added to Australia’s list of formal diseases in 2019.

The alarming fact is many Australians are unaware that they are experiencing sarcopenia and mistakenly dismiss symptoms as a normal part of ageing. Because of this, they rarely discuss the difficulties they are having with mobility or other common activities of daily living, such as walking up a flight of stairs, getting out of a chair, or opening a jar, with their health care provider.

With the ageing process, there are many factors that can lead to a decline in muscle mass and a loss in strength and function. Physical inactivity and a sedentary lifestyle are strong determinants of muscle loss, along with malnutrition (low energy and protein intake) and the presence of acute or chronic disease. Older Australians who are admitted to hospital can experience a significant loss in muscle mass (equivalent to the amount of muscle lost over a decade) because they are sedentary while they are recovering. In fact, older adults with sarcopenia have a 60% likelihood of falls and 70% higher chance of fractures, and are at greater risk for losing their independence and requiring long term care.

Given the current situation with ongoing COVID-19 lockdowns in Australia people are living more sedentary lives. This is an unintended consequence of the stay-at-home directives that have been put in place to keep us safe, and has had an impact on the amount of time people spend exercising and moving regularly to keep their muscles active. As the saying goes, “if you don’t use it, you lose it”, and when it comes to sarcopenia, sometimes you do not know you’re losing it until it is almost too late.

The research by the Australian and New Zealand Society of Sarcopenia and Frailty Research shows that consumers hold a strong recognition of the role of the primary health care provider in diagnosing sarcopenia. It is often difficult to recognise signs and symptoms in patients, especially patients aged in their 50s, because most people in that age group look physically capable. Unless the health care provider performs a test to measure muscle mass, strength or function, evaluating the status of their muscle is challenging. However, we know that muscle deterioration can begin as early as age 40 years and accelerates after the age of 70 years.

While ensuring patients maintain a healthy skeletal muscle mass, it is also important to consider the intricate role that muscles and bone play together in the body. When this intricate partnership between muscle and bone is impaired, it is known as osteosarcopenia. An estimated 66% of Australians over 50 years of age reportedly have osteoporosis or osteopenia. In Australia, there is one minimal trauma fracture every 2.9 minutes (or 3521 fractures per week), and the average cost of osteosarcopenia-associated fractures is estimated at $2.75 billion per year.

For falls prevention, we need to look for the warning signs of sarcopenia.

To identify patients at risk of sarcopenia, I first recommend the 5 Times Chair Stand Test. This test is used to assess functional lower limb muscle strength, transitional movements, and dynamic balance in older adults. How quickly a patient can complete the test is a good indication of how at-risk a person is of developing sarcopenia, or if they are already experiencing impaired muscle function.

My second recommendation is to prescribe older adults resistance (muscle strengthening) training at least twice a week and ensure their diet includes an adequate amount of protein and vitamin D. If the latter is difficult to achieve, a high protein, HMB (hydroxy-β-methylbutyrate), and vitamin D enriched oral nutritional supplement should be considered, as it has been clinically shown to be an effective strategy to improve nutritional status, muscle mass, strength and recovery.

The bottom line is, Australia now has one of the highest life expectancies in the world and in order to help older adults maintain their function, independence and quality of life, a foundation of good nutrition combined with regular physical activity, such as resistance exercise, is the key.

Professor Robin Daly is the Immediate-Past President of the Australian and New Zealand Society for Sarcopenia and Frailty Research, and Chair in Exercise and Ageing within the Institute for Physical Activity and Nutrition at Deakin University.

The statements or opinions expressed in this article reflect the views of the authors and do not represent the official policy of the AMA, the MJA or InSight+ unless so stated.