Osteosarcopenia: A case of geroscience

Abstract

Global aging, attributed to advancements in health care and socioeconomic factors, represents one of the great achievements of the 21st century. However, older age associates with chronic diseases, which could share similar pathophysiology and risk factors; understanding and elucidation of those common mechanisms have enabled the development of geroscience. Musculoskeletal diseases, in particular, represent a significant burden in older persons and a major cost to health systems worldwide. Of those, osteopenia/osteoporosis (characterized by low bone mass) increases with age alongside the number of osteoporotic fractures, 1 while sarcopenia (low muscle mass and function) confers a high risk of falls and disability in older persons. 2 Together, these diseases form a geriatric syndrome known as "osteosarcopenia," 3 which associates with an increased risk of falls, fractures, and hospitalizations in older persons. 4,5 Not only does osteosarcopenia induce billions in health-care expenditure but it also greatly impairs an older person's quality of life. 3,6

Osteosarcopenia: epidemiology, diagnosis, and treatment—facts and numbers

“…A myriad of factors may explain the pathology of osteosarcopenia. First, polymorphisms of the genes glycine‐ N ‐acyltransferase (GLYAT), methyltransferase like 21C (METTL21C), peroxisome proliferator‐activated receptor gamma coactivator 1‐alpha (PGC‐1α), and myocyte enhancer factor‐2 (MEF2C) associate with muscle atrophy and bone loss . In addition, genetic traits determine peak muscle and bone volume in early life, which may be a mechanism for delaying sarcopenia and osteoporosis in late life.…”

“…First, polymorphisms of the genes glycine‐ N ‐acyltransferase (GLYAT), methyltransferase like 21C (METTL21C), peroxisome proliferator‐activated receptor gamma coactivator 1‐alpha (PGC‐1α), and myocyte enhancer factor‐2 (MEF2C) associate with muscle atrophy and bone loss . In addition, genetic traits determine peak muscle and bone volume in early life, which may be a mechanism for delaying sarcopenia and osteoporosis in late life. Second, gravitational loading (via external ground forces or internal muscle contractions) is transferred from muscle to the skeleton, providing the mechanical stimuli to maintain bone density .…”

“…The World Health Organization defines osteopenia and osteoporosis as a T score equal to or less than −1 and −2.5 standard deviations, respectively, below the peak bone mass of a young healthy cohort or in the presence of a minimal‐trauma fracture . This skeletal disease reduces bone microarchitecture and impedes bone strength .…”

“…The World Health Organization defines osteopenia and osteoporosis as a T score equal to or less than −1 and −2.5 standard deviations, respectively, below the peak bone mass of a young healthy cohort or in the presence of a minimal‐trauma fracture . This skeletal disease reduces bone microarchitecture and impedes bone strength . On the other hand, sarcopenia is characterized by cut‐off values for low muscle mass, strength, and/or functional capacity and associates with a range of metabolic conditions .…”

“…Osteosarcopenia was first coined by Duque and colleagues to describe a subset of older persons affected by osteoporosis and sarcopenia. It is important to note that osteosarcopenia is a unique syndrome, defined by the combination of low bone density (osteopenia/osteoporosis) and muscle mass, strength, and/or functional capacity (sarcopenia) . As a consequence of an aging population, which will see an increase in older persons (≥60 years) from ~841 million in 2013 to ~2 billion by 2050 (proportional increase of 9%), the prevalence of osteosarcopenia will inevitably increase, resulting in a greater number of falls, fractures, and hospitalizations.…”