Understanding the development of sarcopenic obesity

ABSTRACT

Introduction

Sarcopenic obesity (SarcO) is defined as the confluence of reduced muscle mass and function and excess body fat. The scientific community is increasingly recognizing this syndrome, which affects a subgroup of persons across their lifespans and places them at synergistically higher risk of significant medical comorbidity and disability than either sarcopenia or obesity alone. Joint efforts in clinical and research settings are imperative to better understand this syndrome and drive the development of urgently needed future interventions.

Areas covered

Herein, we describe the ongoing challenges in defining sarcopenic obesity and the current state of the science regarding its epidemiology and relationship with adverse events. The field has demonstrated an emergence of data over the past decade which we will summarize in this article. While the etiology of sarcopenic obesity is complex, we present data on the underlying pathophysiological mechanisms that are hypothesized to promote its development, including age-related changes in body composition, hormonal changes, chronic inflammation, and genetic predisposition.

Expert opinion

We describe emerging areas of future research that will likely be needed to advance this nascent field, including changes in clinical infrastructure, an enhanced understanding of the lifecourse, and potential treatments.

KEYWORDS:

• Aging
• body composition
• epidemiology
• function
• inflammation
• mechanisms
• obesity
• sarcopenia

Article highlights

• Sarcopenic Obesity is currently defined as the loss of muscle mass and function in conjunction with excess body fat;

• Sarcopenic obesity exists across the lifecourse; however, it is increasingly prevalent with advancing age, and is strongly associated with multiple chronic conditions, higher risk of institutionalization and death, and poor quality of life;

• A complex, multifactorial interplay of factors likely predicts the development and onset of sarcopenic obesity, including changes in body composition, chronic underlying inflammatory burden, ectopic and visceral fat deposition particularly in the muscle (myosteatosis), hormonal changes, and multifaceted cytokine/myokine signaling;

• Longstanding dietary and exercise habits that begin early in life are believed to be at the root of its development;

• Future research is needed to overcome barriers to routine implementation of sarcopenic obesity screening and diagnosis in clinical practice, and additional clinical trials using emerging therapeutics are needed in this population.

Declaration of interest

J Batsis owns equity in SynchroHealth LLC. The authors have no other relevant affiliations or financial involvement with any organization or entity with a financial interest in or financial conflict with the subject matter or materials discussed in the manuscript apart from those disclosed.

The authors have no other relevant affiliations or financial involvement with any organization or entity with a financial interest in or financial conflict with the subject matter or materials discussed in the manuscript apart from those disclosed.

Reviewer disclosures

Peer reviewers on this manuscript have no relevant financial or other relationships to disclose.

Additional information

Funding

This research was supported in part by the National Institute on Aging under Award Number [K23AG051681 and R01AG077163-01A1] supported through the National Institute on Aging, The North Carolina Translational and Clinical Sciences (NC TraCS) Institute, which is supported by the National Center for Advancing Translational Sciences (NCATS) through Grant Award Number [UL1TR002489], the University of North Carolina Centers for Aging and Health, and the Nutrition Obesity Research Center supported from the National Institute of Diabetes and Digestive and Kidney Diseases [P30-DK056350].