Muscle Matters: Cracking the Code of Sarcopenia

To celebrate World Sarcopenia Day, Professor Carolyn Greig, co-lead of the Birmingham BRC Sarcopenia and Multimorbidity research theme, talks us through this condition and the research we’re doing to improve the lives of patients.

What is sarcopenia?

Sarcopenia is typically defined as age-related loss of skeletal muscle mass and function. However, there’s more to it than that: sarcopenia is also an inherent complication of chronic inflammatory diseases, as well as advancing age. In the UK, 58% of those aged 60 years or older have two or more long term conditions, most of them inflammatory in nature.

Sarcopenia reduces the ability to do normal everyday tasks and activities which are important for the maintenance of physical independence, such as climbing stairs or getting out of a chair. There is also an increased risk of frailty and physical disability. Many people with long term diseases and conditions may experience sarcopenia – and of course the reduced physical activity and increase in sedentariness, which is also often present, may further drive muscle loss.

Not only is sarcopenia a societal problem, it is also an economic one. The excess healthcare costs alone for the UK have been estimated as £2.5 billion each year. In addition, poor musculoskeletal health in the UK was one of the leading causes preventing people aged 60-64 years from working in 2022.

The effects of muscle loss are not experienced evenly across society, because sex and social environment strongly drive health inequalities in ageing. As Birmingham has a high level of social deprivation, reducing sarcopenia and multimorbidity will help to address these health inequalities and reduce NHS and social care costs.

What are the available treatments for sarcopenia?

Currently the best ‘treatment’ for sarcopenia is exercise, and specifically resistance exercise, which loads muscles and bones. Exercise combined with protein nutrition has also been shown to be effective in improving muscle health. However, these types of lifestyle intervention may not be for everyone: Our Muscle Health public contributor group tell us that “many adults do not like exercising because it’s inconvenient or because they find it difficult”.

Another problem is that our research has shown that in older age and with inflammation, muscles do not respond very well to the growth effects of exercise or nutrition – a phenomenon known as ‘anabolic resistance’.

And how about drugs as alternative treatment? Pharmacological approaches to treating sarcopenia have not yet yielded convincing evidence, but this is due in part to limited understanding of the underlying physiological mechanisms, particularly in the context of inflammatory disease.

So, there is a clear need to find new ways to slow down the progression of sarcopenia and to empower people to continue living a physically independent life.

Our research at the Birmingham BRC

Within the NIHR Birmingham BRC Sarcopenia and Multimorbidity theme, we are exploring the underlying causes of muscle loss, with a focus on three different inflammatory diseases: chronic liver disease, inflammatory bowel disease, and rheumatoid arthritis.

We are investigating key elements of muscle metabolism which (i) become deranged with advancing age and chronic inflammatory disease, (ii) are associated with inflammation (a driver of muscle loss), and (iii) we might be able to treat, delivering patient benefit.

At the same time, we are exploring different types of physical activity interventions and tailoring them to make them more acceptable to patients, and therefore more likely to succeed. We have already identified that people living with these inflammatory diseases are sedentary for around 70% of their waking day. Sarcopenia in the presence of inflammatory disease and inactivity is associated with substantial fatty infiltration into muscles – and interestingly, seems to be due to an acceleration of the normal ageing process. This is important, as there are existing drugs that can slow this down.

We are also working on a new area, looking at how the bacteria in the gut change in chronic inflammatory diseases and how this might influence sarcopenia.

Our hopes for the future of sarcopenia

With the support of the Birmingham BRC, our research on defining mechanisms and testing interventions, both lifestyle and pharmaceutical, to counteract sarcopenia, will help us to develop theory-informed, effective and sustainable interventions which can be translated into clinical practice to deliver benefit to patients and the NHS.

This will have direct effects, such as reducing falls and fatigue and improving quality of life by empowering people to maintain functional ability for as long as possible. It will also help to meet the government target of adding 5 more years of healthy, independent living for adults in the UK by 2035, as well as reducing healthcare costs.