Factors Associated with Poor Muscle Mass and Strength in A Community-Dwelling Elderly Population: A Cross-Sectional Study

Abstract

IntroductionA progressive loss of muscle mass occurs from approximately 40 years of age. This loss has been estimated at about 8% per decade until the age of 70 years, after which the loss increases to 15% per decade [1]. Loss of muscle mass accompanied by loss of muscle strength or function is known as sarcopenia [2], a devastating geriatric syndrome leading to frailty, functional decline, disability, falls and even death [3,4]. Muscle mass and function, the main components of the frailty phenotype proposed by Fried [5], are a main determinant of physical performance and quality of life. The pathophysiology of muscle wasting in the older population is multifactorial and not completely understood [6]. Poor physical exercise and poor nutritional status are considered to be the main risk factors for sarcopenia. Other factors such as an imbalance between anabolic and catabolic hormones [7], metabolic disorders and insulin resistance [8] and chronic proinflammatory states have been associated with muscle wasting [9]. However, the specific role of each of these factors in the development of sarcopenia is not well known. Moreover, gender differences exist not only in body composition, muscle mass and strength but also in the prevalence of frailty and disability [10]. Older women are more prone to experiencing accelerated functional decline, and although they live longer than men they usually have a poorer quality of life [11]. These data would suggest that the pathophysiology of sarcopenia and frailty and the role of the above-mentioned risk factors may differ in men and women. A profound knowledge of the mechanisms involved in muscle wasting and sarcopenia is essential to the design of effective preventive measures to reduce both incidence and consequences. We hypothesize that low physical activity, obesity, inflammation and hormonal misbalances are associated with low muscle mass and strength. The aim of this study was to assess the main factors associated with poor muscle mass and strength in a community-dwelling elderly population and to assess differences by sex. Methods Study design and populationAn observational cross-sectional study was performed of community-dwelling adults aged 75 years and older. A sample was randomly selected from the database of 3 primary care centres in the municipalities of Mataró and Argentona (Barcelona, Spain). Individuals were excluded if they had active malignancy, dementia or serious mental illness, had a life expectancy of less than 6 months, were in a palliative care programme or were institutionalized. Persons who fulfilled all selection criteria and who signed the informed consent form were recruited from January to July 2014. The local ethics committee approved the study protocol (code 64/13). Details of the study design have been previously published [12]. AbstractBackground: The pathophysiology of muscle wasting in the elderly is multifactorial and not fully understood.