title: Association of androgen with skeletal muscle mass and muscle function among men and women aged 50 years and older in Taiwan: results from the I-Lan longitudinal aging study.
abstract: OBJECTIVE
  The main aim of this study was to explore the association between skeletal muscle mass and muscle function by three different measures of bioactive testosterone, as well as dehydroepiandrosterone sulfate (DHEA-S) among men and women aged 50 years and older in Taiwan to facilitate further investigations of sarcopenia and androgen profile.
  
  
  METHODS
  The data of 532 participants (mean age 64.6±9.5 years; male, 53.0%) recruited from the I-Lan Longitudinal Aging Study was retrieved for analysis. Appendicular muscle mass, grip strength, and walking speed were stratified into quartiles in both genders to explore their associations with different hormones measures.
  
  
  RESULTS
  Among three different bioactive testosterone measures, the free androgen index had significant positive association with muscle mass (p both <0.001) and muscle strength in both genders (p<0.001 in men and p=0.03 in women), whereas free testosterone and bioavailable testosterone displayed similar correlations only in the skeletal muscle mass of woman (p both <0.001) and muscle strength of men (p=0.007, p=0.002, respectively). Serum levels of DHEA-S were correlated positively with skeletal muscle mass in men (p=0.013) and women aged 65 years and older (p=0.004) and handgrip strength in both genders (p<0.001 in men and p=0.009 in women). None of the bioactive testosterone measurements was associated with walking speed, whereas DHEA-S was significantly positively correlated with gait speed in both genders (p both=0.001).
  
  
  CONCLUSIONS
  In conclusion, the free androgen index increased remarkably along with muscle mass and muscle strength among men and women aged 50 years and older. Moreover, DHEA-S was positively associated with muscle mass in men and older women and muscle strength in both sexes, and was also associated with aging and gait speed in both genders.
authors.affiliation: 1 Aging and Health Research Center, National Yang Ming University , Taipei, Taiwan .
authors.forename: An-Chun
authors.initials: AC
authors.lastname: Hwang
authors.forename: Li-Kuo
authors.initials: LK
authors.lastname: Liu
authors.forename: Wei-Ju
authors.initials: WJ
authors.lastname: Lee
authors.forename: Liang-Yu
authors.initials: LY
authors.lastname: Chen
authors.forename: Ming-Hsien
authors.initials: MH
authors.lastname: Lin
authors.forename: Li-Ning
authors.initials: LN
authors.lastname: Peng
authors.forename: Chang Won
authors.initials: CW
authors.lastname: Won
authors.forename: Liang-Kung
authors.initials: LK
authors.lastname: Chen
mesh_terms: D000368:Aged; D000728:Androgens / Q000502:physiology*; D015331:Cohort Studies; D005260:Female; D006801:Humans; D008137:Longitudinal Studies; D008297:Male; D008875:Middle Aged; D018482:Muscle, Skeletal / Q000502:physiology*; D009929:Organ Size / Q000502:physiology*; D013624:Taiwan
chemical_list: D000728:Androgens