title: Quadriceps sarcopenia and visceral obesity are risk factors for postural instability in the middle-aged to elderly population.
abstract: OBJECTIVE
  Aging shifts body composition to comprising more fat and less muscle. Sarcopenia, particularly in the knee extensors, and obesity, particularly visceral obesity, either alone or in combination, may exacerbate age-related physical disability. We investigated the association between age-related quadriceps (Qc) sarcopenia and visceral obesity, as measured by cross-sectional area (CSA), on postural instability.
  
  
  METHODS
  Mid-thigh muscle CSA and abdominal visceral and subcutaneous fat area at the level of the umbilicus were assessed from computed tomography (CT) images in 410 apparently healthy independent middle-aged to elderly subjects attending the medical check-up program in Ehime University Hospital. Static postural instability using a posturograph and one-leg standing time with eyes open were assessed.
  
  
  RESULTS
  Both abdominal visceral fat area and Qc muscle CSA corrected by body weight (BW) were associated with static postural instability, in addition to age and sex, while BW-corrected Qc muscle CSA predicted a short one-leg standing time. The combination of Qc sarcopenia, defined as greater than 1 standard deviation below the mean of a young group (age <60 years), and visceral obesity, defined as a visceral fat area of more than 100 cm(2), were associated with static postural instability, while Qc sarcopenia was related to a higher prevalence of one-leg standing time of less than 30 s, irrespective of visceral obesity.
  
  
  CONCLUSIONS
  Thigh Qc sarcopenia and visceral obesity are associated with postural instability in middle-aged to elderly subjects. These findings suggest that age-related, site-specific fat and muscle mass alterations are associated with functional impairment.
authors.affiliation: Department of Geriatric Medicine, Ehime Proteo-Medicine Research Center, Ehime Graduate School of Medicine, Ehime, Japan.
authors.forename: Masayuki
authors.initials: M
authors.lastname: Ochi
authors.forename: Yasuharu
authors.initials: Y
authors.lastname: Tabara
authors.forename: Tomoko
authors.initials: T
authors.lastname: Kido
authors.forename: Eri
authors.initials: E
authors.lastname: Uetani
authors.forename: Namiko
authors.initials: N
authors.lastname: Ochi
authors.forename: Michiya
authors.initials: M
authors.lastname: Igase
authors.forename: Tetsuro
authors.initials: T
authors.lastname: Miki
authors.forename: Katsuhiko
authors.initials: K
authors.lastname: Kohara
mesh_terms: D000367:Age Factors; D000368:Aged; D000375:Aging / Q000502:physiology; D005260:Female; D006801:Humans; D050152:Intra-Abdominal Fat / Q000000981:diagnostic imaging; D008297:Male; D008875:Middle Aged; D009048:Motor Skills; D056128:Obesity, Abdominal / Q000150:complications* / Q000000981:diagnostic imaging; D004856:Postural Balance; D052097:Quadriceps Muscle / Q000000981:diagnostic imaging; D055948:Sarcopenia / Q000150:complications* / Q000000981:diagnostic imaging; D012678:Sensation Disorders / Q000209:etiology*; D014057:Tomography, X-Ray Computed