Over the past two decades, many international groups have formulated definitions for sarcopenia, including reduced muscle function alongside low muscle mass. These definitions have proven successful in advancing the field an introducing the term into the revised version of the International Classification of Diseases, Clinical Modification.

However, the absence of consensus among widely used definitions is currently impeding progress in the field, affecting both research and the integration of sarcopenia into routine clinical practice. It is crucial to establish a universally accepted definition of sarcopenia that can be applied worldwide. This step is necessary to further propel advancements in the field and ultimately enhance the care of patients with sarcopenia and to prevent its consequences.

GLIS

GLIS stands for Global Leadership Initiative in Sarcopenia, a project aimed at creating an all-encompassing definition of sarcopenia with widespread acceptance and adoption by existing consensus groups that have proposed definitions that are currently used. All these groups are part of GLIS: the Australian and New Zealand Society for Sarcopenia and Frailty Research (ANZSSFR), Asian Working Group for Sarcopenia (AWGS), European Working Group on Sarcopenia in Older People (EWGSOP), Sarcopenia Definitions and Outcomes Consortium (SDOC) and the sarcopenic obesity consensus group.

The following societies and organizations have agreed to nominate experts to participate in the GLIS steering committee:

• Aging in Motion (AIM) coalition / Alliance for Aging Research (AAR)
• American Geriatrics Society (AGS) 
• American Society for Bone and Mineral Research (ASBMR) 
• Asian Association for Frailty and Sarcopenia (AAFS)
• Australian and New Zealand Society for Sarcopenia and Frailty Research (ANZSSFR)
• European Association for the Study of Obesity (EASO)
• European Geriatric Medicine Society (EuGMS)
• European Society for Clinical and Economic Aspects of Osteoporosis, Osteoarthritis and Musculoskeletal Diseases (ESCEO)
• European Society for Clinical Nutrition and Metabolism (ESPEN)
• Gerontological Society of America (GSA)
• International Association of Gerontology and Geriatrics (IAGG)
• International Conference on Frailty and Sarcopenia Research (ICFSR)
• International Osteoporosis Foundation (IOF)
• Society on Sarcopenia, Cachexia and Wasting Disorders (SCWD)

STEERING COMMITTEE

This initiative commenced in August 2021 through a working group assembled by select members from the aforementioned consensus groups. Extensive discussion centred on the necessity for a consensus and the approaches to achieve it. Over time, various societies and organizations consented to join the initiative, designating a representative to contribute to the committee. Eventually, the steering committee comprised the following members:

GLIS GROUP

In line with GLIS's dedication to inclusivity, all members from participating working groups were invited to join the initiative. Furthermore, each participating organisation nominated additional members to contribute to GLIS. An effort was made to identify and invite experts from regions of the world usually excluded from such initiatives. All members were required to demonstrate expertise and a track record of publications in the field of sarcopenia. In order to participate in the initiative, all individuals had to disclose any potential conflicts of interest.

Finally, 107 participants (mean age 54 years, 36% women) from 29 countries across 7 continents/regions conformed the GLIS group. (Click here to open the list)

WHAT HAS GLIS ACCOMPLISHED SO FAR?

The initial step involved building a glossary that defines terms commonly related to sarcopenia, aimed at establishing uniformity in language. This glossary has been published and is available here

The subsequent stage focused on formulating a mutually agreed conceptual definition of the fundamental elements of sarcopenia, forming the basis for a future operational definition. To achieve this, the steering committee prepared a set of statements and used a modified Delphi method, engaging participation from both of the steering committee and the GLIS group. Statements were assessed using a standardised procedure of acceptance or rejection.      
The article proposing this conceptual definition is now complete and has been accepted by Age Ageing, where it will be published fast track.

WHAT'S ON THE HORIZON FOR GLIS?

Presently, the GLIS initiative has instituted three working groups. Led by select members of the steering committee, they will collaborate with the GLIS group to investigate the standardization of assessments for:

• Muscle mass           
• Muscle function           
• Outcomes of sarcopenia           
 

Further details will be provided upon the publication of the conceptual definition.

CAN I JOIN GLIS?

GLIS welcomes new members for its ongoing and forthcoming projects. However, to maintain diversity and inclusivity, not all applicants will be accepted. Specifically, we discourage multiple applications from individuals within the same institution.

If you wish to join GLIS, kindly submit your candidacy via email to Katrin Werner, with a brief CV showcasing your expertise and publications in the field. All CVs will undergo review by the steering committee, following which a decision will be made.