title: The association between physiologic testosterone levels, lean mass, and fat mass in a nationally representative sample of men in the United States.
abstract: Testosterone deficiency leads to increased muscle loss with aging and increased fat mass. Supraphysiologic levels cause an increase in muscle mass and decrease in fat mass. The difference in lean and fat mass across physiologic levels of testosterone has been under examined in men.
  
  
  
  Examine the association between physiologic testosterone levels with lean and fat mass.
  
  
  
  Data from the 1999-2000 NHANES were used (n=252 men; 18-85yrs). Testosterone and SHBG values were obtained by a morning blood sample. Body composition was measured by DXA. Multivariable linear regression was used to compute unadjusted, minimally adjusted, and extended models of relative upper- and lower-body lean and fat mass.
  
  
  
  In the extended model, men with total testosterone levels in the highest 25% (4th quartile) had more lower-body lean mass (LBLM) (β=22.1(%), 95%CI: 9.0, 35.3, p=0.003) and upper-body lean mass (UBLM) (β=5.6(%), 95%CI: 0.1, 11.2, p=0.046), and less lower-body fat mass (LBFM) (β=-9.9(%), 95%CI: -17.7, -2.1, p=0.016) and upper-body fat mass (UBFM) (β=-6.1(%), 95%CI: -10.1, -2.1, p=0.005) than those in the 1st quartile. Men in the 3rd quartile had more LBLM (β=14.2, 95%CI: 5.3, 23.1, p=0.004), UBLM (β=5.6, 95%CI: 2.0, 9.2, p=0.004), and less LBFM (β=-9.7(%), 95%CI: -16.7, -2.7, p=0.010) and UBFM (β=-4.7(%), 95%CI: -8.3, -1.2, p=0.012) than those in the 1st quartile.
  
  
  
  These findings suggest that, at physiologic levels, an association exists between higher levels of testosterone and favorable lean and fat measures.
authors.affiliation: Department of Health, Exercise Science and Recreation Management, Kevser Ermin Applied Physiology Laboratory, The University of Mississippi, University, MS, United States.
authors.forename: J Grant
authors.initials: JG
authors.lastname: Mouser
authors.affiliation: Department of Health, Exercise Science and Recreation Management, Center for Health Behavior Research, The University of Mississippi, University, MS, United States.
authors.forename: Paul D
authors.initials: PD
authors.lastname: Loprinzi
authors.affiliation: Department of Health, Exercise Science and Recreation Management, Kevser Ermin Applied Physiology Laboratory, The University of Mississippi, University, MS, United States. Electronic address: jploenne@olemiss.edu.
authors.forename: Jeremy P
authors.initials: JP
authors.lastname: Loenneke
mesh_terms: D000273:Adipose Tissue / Q000378:metabolism; D000328:Adult; D001823:Body Composition / Q000502:physiology; D006801:Humans; D008297:Male; D008875:Middle Aged; D018482:Muscle, Skeletal / Q000378:metabolism; D013739:Testosterone / Q000378:metabolism*; D014481:United States
chemical_list: D013739:Testosterone
keywords: Body composition; Physiologic levels; Replacement therapy; Testosterone