title: Sex- and age-related differences in mid-thigh composition and muscle quality determined by computed tomography in middle-aged and elderly Japanese.
abstract: OBJECTIVE
  Sex- and age-related differences in mid-thigh composition and muscle quality remain unclear. The present study aimed to clarify these differences using computed tomography in middle-aged and elderly Japanese.
  
  
  METHODS
  A total of 2310 participants (age 40-89 years), who were randomly selected from the local residents, underwent computed tomography examination of the right mid-thigh. Thigh circumference and cross-sectional areas of the thigh, muscle, quadriceps, non-quadriceps, fat, and bone were measured. Knee extension strength and muscle quality index (knee extension strength/quadriceps cross-sectional area) were also assessed. Sex- and age-related differences in these indices were analyzed.
  
  
  RESULTS
  The thigh cross-sectional area in men and women decreased by 0.6% and 0.5%/year, respectively, because of a decrease in muscle cross-sectional area (men 75.2%, women 40.6%), fat cross-sectional area (men 24.4%, women 59.6%) and bone cross-sectional area (men 0.5%, women -0.2%). Muscle cross-sectional area in men and women decreased by 0.6% and 0.4%/year, respectively, because of a decrease in quadriceps cross-sectional area (men 65.6%, women 81.6%) and non-quadriceps cross-sectional area (men 34.4%, women 18.4%). Muscle quality in men and women decreased by 0.4% and 0.3%/year, respectively.
  
  
  CONCLUSIONS
  Thigh cross-sectional area decreased with age mainly because of a decrease in muscle cross-sectional area in men and fat cross-sectional area in women. The rate of decrease in muscle cross-sectional area was 1.5-fold higher in men than in women. Muscle cross-sectional area decreased with age mainly because of a decrease in quadriceps cross-sectional area, especially in women. Decrease in muscle quality with age was similar in both sexes.
authors.affiliation: Department of Orthopedic Surgery, Nagoya University Graduate School of Medicine, Nagoya, Japan.|Department of Orthopedic Surgery, National Center for Geriatrics and Gerontology, Obu, Japan.
authors.forename: Takehiro
authors.initials: T
authors.lastname: Kasai
authors.affiliation: Department of Orthopedic Surgery, Nagoya University Graduate School of Medicine, Nagoya, Japan.
authors.forename: Naoki
authors.initials: N
authors.lastname: Ishiguro
authors.affiliation: Department of Orthopedic Surgery, National Center for Geriatrics and Gerontology, Obu, Japan.
authors.forename: Yasumoto
authors.initials: Y
authors.lastname: Matsui
authors.affiliation: Department of Orthopedic Surgery, National Center for Geriatrics and Gerontology, Obu, Japan.
authors.forename: Atsushi
authors.initials: A
authors.lastname: Harada
authors.affiliation: Department of Orthopedic Surgery, National Center for Geriatrics and Gerontology, Obu, Japan.
authors.forename: Marie
authors.initials: M
authors.lastname: Takemura
authors.affiliation: Faculty of Education, Kochi University, Kochi, Japan.
authors.forename: Atsumu
authors.initials: A
authors.lastname: Yuki
authors.affiliation: Section of NILS-LSA, Center for Gerontology and Social Science, National Center for Geriatrics and Gerontology, Obu, Japan.
authors.forename: Yuki
authors.initials: Y
authors.lastname: Kato
authors.affiliation: Section of NILS-LSA, Center for Gerontology and Social Science, National Center for Geriatrics and Gerontology, Obu, Japan.
authors.forename: Rei
authors.initials: R
authors.lastname: Otsuka
authors.affiliation: Faculty of Health and Medical Science, Aichi Shukutoku University, Nagakute, Japan.
authors.forename: Fujiko
authors.initials: F
authors.lastname: Ando
authors.affiliation: Graduate School of Nutritional Sciences, Nagoya University of Arts and Sciences, Nisshin, Japan.
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Shimokata
mesh_terms: D000328:Adult; D000367:Age Factors; D000368:Aged; D000369:Aged, 80 and over; D044466:Asian People; D005260:Female; D006801:Humans; D007564:Japan / Q000453:epidemiology; D008297:Male; D008875:Middle Aged; D018482:Muscle, Skeletal / Q000000981:diagnostic imaging; D055948:Sarcopenia / Q000453:epidemiology*; D012737:Sex Factors; D013848:Thigh / Q000033:anatomy & histology*; D014057:Tomography, X-Ray Computed
keywords: aging; computed tomography; mid-thigh composition; muscle mass; muscle quality