title: Effects of Testosterone Supplementation for 3 Years on Muscle Performance and Physical Function in Older Men.
abstract: Findings of studies of testosterone's effects on muscle strength and physical function in older men have been inconsistent; its effects on muscle power and fatigability have not been studied.
  
  
  
  To determine the effects of testosterone administration for 3 years in older men on muscle strength, power, fatigability, and physical function.
  
  
  
  This was a double-blind, placebo-controlled, randomized trial of healthy men ≥60 years old with total testosterone levels of 100 to 400 ng/dL or free testosterone levels <50 pg/mL.
  
  
  
  Random assignment to 7.5 g of 1% testosterone or placebo gel daily for 3 years.
  
  
  
  Loaded and unloaded stair-climbing power, muscle strength, power, and fatigability in leg press and chest press exercises, and lean mass at baseline, 6, 18, and 36 months.
  
  
  
  The groups were similar at baseline. Testosterone administration for 3 years was associated with significantly greater performance in unloaded and loaded stair-climbing power than placebo (mean estimated between-group difference, 10.7 W [95% confidence interval (CI), -4.0 to 25.5], P = 0.026; and 22.4 W [95% CI, 4.6 to 40.3], P = 0.027), respectively. Changes in chest-press strength (estimated mean difference, 16.3 N; 95% CI, 5.5 to 27.1; P < 0.001) and power (mean difference 22.5 W; 95% CI, 7.5 to 37.5; P < 0.001), and leg-press power were significantly greater in men randomized to testosterone than in those randomized to placebo. Lean body mass significantly increased more in the testosterone group.
  
  
  
  Compared with placebo, testosterone replacement in older men for 3 years was associated with modest but significantly greater improvements in stair-climbing power, muscle mass, and power. Clinical meaningfulness of these treatment effects and their impact on disability in older adults with functional limitations remains to be studied.
authors.affiliation: Research Program in Men's Health: Aging and Metabolism, Boston Claude D. Pepper Older Americans Independence Center, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts 02115.
authors.forename: Thomas W
authors.initials: TW
authors.lastname: Storer
authors.affiliation: Research Program in Men's Health: Aging and Metabolism, Boston Claude D. Pepper Older Americans Independence Center, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts 02115.
authors.forename: Shehzad
authors.initials: S
authors.lastname: Basaria
authors.affiliation: Kronos Longevity Research Institute, Phoenix, Arizona 85016.|Northern Arizona University, Flagstaff, Arizona 86011.
authors.forename: Tinna
authors.initials: T
authors.lastname: Traustadottir
authors.affiliation: Kronos Longevity Research Institute, Phoenix, Arizona 85016.|Phoenix VA Health Care System, Phoenix, Arizona 85012.
authors.forename: S Mitchell
authors.initials: SM
authors.lastname: Harman
authors.affiliation: Research Program in Men's Health: Aging and Metabolism, Boston Claude D. Pepper Older Americans Independence Center, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts 02115.
authors.forename: Karol
authors.initials: K
authors.lastname: Pencina
authors.affiliation: Research Program in Men's Health: Aging and Metabolism, Boston Claude D. Pepper Older Americans Independence Center, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts 02115.
authors.forename: Zhuoying
authors.initials: Z
authors.lastname: Li
authors.affiliation: Research Program in Men's Health: Aging and Metabolism, Boston Claude D. Pepper Older Americans Independence Center, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts 02115.|Institute for Aging Research, Hebrew Senior Life, Boston, Massachusetts 02131.
authors.forename: Thomas G
authors.initials: TG
authors.lastname: Travison
authors.affiliation: Division of Endocrinology, Boston University School of Medicine, Boston, Massachusetts 02118.|Harvard T.H. Chan School of Public Health, Boston, Massachusetts 02115.
authors.forename: Renee
authors.initials: R
authors.lastname: Miciek
authors.affiliation: Kronos Longevity Research Institute, Phoenix, Arizona 85016.|DWR Department of Geriatric Medicine, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma 73104; and.
authors.forename: Panayiotis
authors.initials: P
authors.lastname: Tsitouras
authors.affiliation: Research Program in Men's Health: Aging and Metabolism, Boston Claude D. Pepper Older Americans Independence Center, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts 02115.
authors.forename: Kathleen
authors.initials: K
authors.lastname: Hally
authors.affiliation: Research Program in Men's Health: Aging and Metabolism, Boston Claude D. Pepper Older Americans Independence Center, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts 02115.
authors.forename: Grace
authors.initials: G
authors.lastname: Huang
authors.affiliation: Research Program in Men's Health: Aging and Metabolism, Boston Claude D. Pepper Older Americans Independence Center, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts 02115.
authors.forename: Shalender
authors.initials: S
authors.lastname: Bhasin
mesh_terms: D000368:Aged; D000375:Aging / Q000097:blood / Q000187:drug effects / Q000502:physiology*; D001823:Body Composition / Q000187:drug effects / Q000502:physiology*; D015992:Body Mass Index; D004311:Double-Blind Method; D020249:Hormone Replacement Therapy / Q000379:methods*; D006801:Humans; D008297:Male; D008875:Middle Aged; D053580:Muscle Strength / Q000187:drug effects / Q000502:physiology*; D018482:Muscle, Skeletal / Q000187:drug effects / Q000502:physiology*; D017063:Outcome Assessment, Health Care; D010809:Physical Fitness / Q000502:physiology*; D013739:Testosterone / Q000008:administration & dosage / Q000097:blood* / Q000494:pharmacology*
chemical_list: D013739:Testosterone