title: Muscle function and fat content in relation to sarcopenia, obesity and frailty of old age--An overview.
abstract: OBJECTIVE
  In western countries, the proportion of people over age 60 is increasing faster than any other group. This is linked to higher rates of obesity. Older age, co-morbidities and obesity are all associated with frailty syndrome. In the core of both frailty and sarcopenia there are dysfunction and deterioration of the muscle and the fat tissues. This overview interlinks the phenotypes presented in older adults such as sarcopenia and frailty-alone and with relation to obesity, muscle function and fat tissue accumulation.
  
  
  RESULTS
  Observational studies have well described the loss of muscle mass and strength through the years of adult life, both components of frailty and sarcopenia. They have shown that these changes are associated with dysmetabolism and functional deterioration, independent of common explanatory variables. In the metabolic mechanism core of this link, insulin resistance and higher ectopic fat accumulation may play a role. Basic experiments have partially validated this hypothesis. Whether there is a synergistic effect of obesity and frailty phenotype on morbidity risk is still questionable and currently under investigation; however, few cohort studies have shown that the frail-obese or sarcopenic-obese group have higher probability for metabolic complications.
  
  
  CONCLUSIONS
  Muscle mass loss and fat accumulation in the muscle in the elderly, with or without the presence of obesity, may explain some of the functional and metabolic defects shown in the frail, sarcopenic population.
authors.affiliation: Institute of Endocrinology, Metabolism and Hypertension, Tel Aviv Sourasky Medical Center, Tel-Aviv, Israel; The Sackler Faculty of Medicine, Tel-Aviv University, Israel. Electronic address: buchasaf@gmail.com.
authors.forename: Assaf
authors.initials: A
authors.lastname: Buch
authors.affiliation: Institute of Endocrinology, Metabolism and Hypertension, Tel Aviv Sourasky Medical Center, Tel-Aviv, Israel; School of Public Health, Haifa University, Haifa, Israel.
authors.forename: Eli
authors.initials: E
authors.lastname: Carmeli
authors.affiliation: School of Public Health, Haifa University, Haifa, Israel.
authors.forename: Lital Keinan
authors.initials: LK
authors.lastname: Boker
authors.affiliation: Institute of Endocrinology, Metabolism and Hypertension, Tel Aviv Sourasky Medical Center, Tel-Aviv, Israel; The Sackler Faculty of Medicine, Tel-Aviv University, Israel.
authors.forename: Yonit
authors.initials: Y
authors.lastname: Marcus
authors.affiliation: Institute of Endocrinology, Metabolism and Hypertension, Tel Aviv Sourasky Medical Center, Tel-Aviv, Israel; The Sackler Faculty of Medicine, Tel-Aviv University, Israel.
authors.forename: Gabi
authors.initials: G
authors.lastname: Shefer
authors.affiliation: Institute of Endocrinology, Metabolism and Hypertension, Tel Aviv Sourasky Medical Center, Tel-Aviv, Israel.
authors.forename: Ofer
authors.initials: O
authors.lastname: Kis
authors.affiliation: The Sackler Faculty of Medicine, Tel-Aviv University, Israel; Meir Medical Center, Kfar Saba, Israel.
authors.forename: Yitshal
authors.initials: Y
authors.lastname: Berner
authors.affiliation: Institute of Endocrinology, Metabolism and Hypertension, Tel Aviv Sourasky Medical Center, Tel-Aviv, Israel; The Sackler Faculty of Medicine, Tel-Aviv University, Israel.
authors.forename: Naftali
authors.initials: N
authors.lastname: Stern
mesh_terms: D050154:Adiposity; D000367:Age Factors; D000368:Aged; D000375:Aging; D004734:Energy Metabolism; D016330:Frail Elderly; D015577:Geriatric Assessment; D006801:Humans; D007333:Insulin Resistance; D008875:Middle Aged; D053580:Muscle Strength; D018482:Muscle, Skeletal / Q000378:metabolism / Q000503:physiopathology*; D009765:Obesity / Q000150:complications* / Q000378:metabolism / Q000503:physiopathology; D010641:Phenotype; D012307:Risk Factors; D055948:Sarcopenia / Q000209:etiology* / Q000378:metabolism / Q000503:physiopathology
keywords: Fat mass; Frailty; Muscle function; Muscle mass; Obese frail; Sarcopenia; Sarcopenic obese