title: Body composition changes in stable-weight elderly subjects: the effect of sex.
abstract: OBJECTIVE
  Although cross-sectional and longitudinal studies have shown age-related changes in body composition and fat distribution, they may be related to body weight changes. The aim of this study was to evaluate yearly age-related changes in body composition and fat distribution, over a two-year period, in 101 women and 60 men (age range: 68 to 78 years at baseline).
  
  
  METHODS
  Body composition was evaluated by dual energy X-ray absorptiometry (DXA), and fat distribution by waist and hip circumferences and waist-to-hip circumference ratio. Baseline free testosterone, IGF-1 and serum albumin were evaluated in all subjects, as well as physical activity. Clinical evaluation was performed at baseline and yearly in order to exclude subjects with any condition inducing pathological changes in body composition or fat distribution. Subjects with a weight change > 5% of their baseline body weight during the study period, were excluded.
  
  
  RESULTS
  Significant increases occurred in Body Mass Index (BMI) (1.18% in women, 1.13% in men), waist (1.75% in women, 1.39% in men), and hip circumference (1.06% in women, 1.31% in men), whereas height decreased significantly in both men (0.42%) and women (0.55%). Significant increases in total body fat (1.31%) and percent body fat (1.27%) were observed in women but not in men. Lean body mass did not change significantly throughout the study in either sex. Significant losses in leg muscle mass and appendicular skeletal muscle mass (ASM), calculated as the sum of arm and leg fat-free soft tissue, were observed in men (respectively 3.56 and 2.77%) and women (respectively 2.41 and 1.59%). A significant decrease in ASM adjusted by stature (ASM/height2), a proposed proxy for sarcopenia, was found in men only (1.97%). The rates of loss in leg muscle mass and appendicular muscle mass were significantly higher in men than in women, even after adjusting for free testosterone, IGF-1, physical activity and serum albumin.
  
  
  CONCLUSIONS
  These data demonstrate significant changes in body composition and fat distribution in independently living, weight-stable elderly men and women. These changes are dependent on sex and independent of physical activity, hormones or serum albumin.
authors.affiliation: Chair of Geriatrics, University of Verona, Verona, Italy. mzamboni@univr.it
authors.forename: Mauro
authors.initials: M
authors.lastname: Zamboni
authors.forename: Elena
authors.initials: E
authors.lastname: Zoico
authors.forename: Tiziana
authors.initials: T
authors.lastname: Scartezzini
authors.forename: Gloria
authors.initials: G
authors.lastname: Mazzali
authors.forename: Paolo
authors.initials: P
authors.lastname: Tosoni
authors.forename: Alessandra
authors.initials: A
authors.lastname: Zivelonghi
authors.forename: Dympna
authors.initials: D
authors.lastname: Gallagher
authors.forename: Giovanni
authors.initials: G
authors.lastname: De Pergola
authors.forename: Vincenzo
authors.initials: V
authors.lastname: Di Francesco
authors.forename: Ottavio
authors.initials: O
authors.lastname: Bosello
mesh_terms: D015502:Absorptiometry, Photon; D000273:Adipose Tissue / Q000033:anatomy & histology; D000368:Aged / Q000502:physiology*; D001823:Body Composition / Q000502:physiology*; D015992:Body Mass Index; D001835:Body Weight; D005260:Female; D006304:Health Status; D006801:Humans; D007334:Insulin-Like Growth Factor I / Q000378:metabolism; D008297:Male; D018482:Muscle, Skeletal / Q000033:anatomy & histology; D009929:Organ Size; D012727:Sex Characteristics; D013739:Testosterone / Q000097:blood
chemical_list: D013739:Testosterone; D007334:Insulin-Like Growth Factor I