Sarcopenia is an aging-associated condition, which is currently characterized by the loss of muscle mass and muscle strength. However, there is no consensus regarding its characterization hitherto. As the world older adult population is on the rise, the impact of sarcopenia becomes greater. Due to the lack of effective treatments, sarcopenia is still a persisting problem among the global older adults and should not be overlooked. As a result, it is vital to investigate deeper into the mechanism underlying the pathogenesis of sarcopenia in order to develop more effective therapeutic interventions and to inscribe a more uniform characterization. The etiology of sarcopenia is currently found to be multifactorial, and most of the pharmacological researches are focused on the muscular factors in aging. Although the complete mechanism underlying the development of sarcopenia is still waiting to be elucidated, we propose in this article that the primary trigger of sarcopenia may be neurogenic in origin based on the intimate relationship between the nervous and muscular system, namely, the motor neuron and its underlying muscle fibers. Both of them are affected by the cellular environment and their physiological activity. 1. Introduction Sarcopenia (Greek: sarx means “flesh,” penia means “loss”) is an age-related geriatric syndrome first described on a meeting in 1988 by Dr. Rosenberg as a phenomenon whereby the age-related decline in lean body mass affects ambulation, mobility, energy intake, overall nutrient intake and status, independence, and breathing [1]. More recently, sarcopenia is characterized by the gradual loss of muscle mass, muscle strength, and muscle function/quality in aging [2, 3]. However, there are studies indicating that sarcopenia should be referred only as the age-related loss in muscle mass whilst the age-related loss in muscle strength should be isolated as a new condition called “dynapenia” based on the evidences indicating that the loss of muscle mass and strength are two distinct processes with different pathophysiology [4]. Hitherto, there is no consistent data among a variety of prevalence studies probably due to the difference in study sample, definition of sarcopenia, and the assessment tool used [3]. For example, for the population of over 80 years old, American study of New Mexico Elder Health Survey has found that there were >40% of women and 50% of men who were sarcopenic whilst the NHANES III database study reveals that 11% of women and 7% of men were sarcopenic. Also, the Italian study of InCHIANTI cohort reveals that 15%
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