As it ages, the body weakens. This is due, in particular, to the loss of muscle mass as well as muscle quality. This phenomenon was only objectified (and named) in 1989, which led to scientific interest in the subject.  “The medical and scientific world are now more interested in sarcopenia but due to the fact that very few studies have been devoted to this geriatric syndrome and its consequences in the short, medium and long term, there is very little epidemiological data available on the subject”, laments Professor Olivier Bruyère, of the Public Health, Epidemiology and Health Economics service of the University of Liege. This is why the University of Liege has initiated the SarcoPhAge study (for Sarcopenia and Physical Impairments with Advancing Age) which has yielded its first results(1).

First observation: studies on the question do not seem to be talking about the same subject …”In fact, there is still no scientific consensus on the definition of sarcopenia”, continues Charlotte Beaudart, a researcher at the Public Health, Epidemiology and Health Economics service of the University of Liege, who devoted her doctoral thesis to this subject, in the context of the SarcoPhAge study, a longitudinal follow-up study which aims to improve knowledge about sarcopenia. “For this study, we chose to use the definition of the European Working Group on Sarcopenia in Older People as our basis, which establishes the fact that sarcopenia is characterized by reduced muscle mass and weakened muscle strength as well as limited physical performance. They also set threshold values which we followed in order to diagnose sarcopenia”.

In order to be able to compare the results obtained and obtain reliable prevalence statistics, there needed to be agreement on the thresholds of muscle loss, physical strength and physical abilities that accompany sarcopenia and on the most adequate methods to evaluate these thresholds.

The SarcoPhAge study

It was for this purpose that the SarcoPhAge study was set up by the University of Liege. Between June 2013 and June 2014, 534 people over the age of 65 volunteered to take part in the study. “The participants were recruited by means of the press and by consultation with the different departments in the University Hospital of Liege. We were surprised by the number of volunteers who were willing to take part in the study”, said a delighted Charlotte Beaudart. All the participants were given some questionnaires to complete on their sociodemographic and medical profile as well as their lifestyle. Several parameters were then listed. “Evidently, muscle mass was measured in the individuals concerned as well as muscle strength or physical performance, which are the traditional parameters used to evaluate sarcopenia. However, we used tools that are currently recommended for evaluating sarcopenia. So, in order to measure muscle mass we used Dual-energy X-ray absorptiometry or DXA, which makes it possible to distinguish “lean” mass (including that of the muscles) from fat mass and bone mineral density. From the appendicular lean mass obtained, we were able to determine a skeletal muscle mass index  for each individual studied, which, together with other tests, makes it possible to diagnose sarcopenia”, explains Professor Olivier Bruyère.

In order to evaluate muscle strength, two dynamometers were used one of which was hydraulic and the other pneumatic. But here too, the different tools used yielded surprising results: “The values provided by these tools varied by up to double according to the type of equipment used, which evidently gave very different readings with regard to prevalence!”, continues Charlotte Beaudart.
Physical performance was measured by subjecting the participants to a series of tests such as getting out of a chair five times, walking four meters and evaluating balance.

(1) Beaudart C., Reginster J-Y., Petermans J., Gillain S., Quabron A., Locquet M., Slomian J., Buckunx F., Bruyère O., Quality of life and physical  components linked to sarcopenia : The SarcoPhAge study, Experimental gerontology, 69, 103-110, 2015