title: Low free testosterone predicts frailty in older men: the health in men study.
abstract: BACKGROUND
  The prevalence of frailty increases, whereas testosterone decreases, as men age. Low testosterone may be a risk factor for development of this syndrome.
  
  
  OBJECTIVE
  Our objective was to determine whether testosterone levels are associated with frailty.
  
  
  METHODS
  We conducted a prospective cohort study.
  
  
  METHODS
  Between 2001 and 2004, frailty was assessed in 3616 community-dwelling men aged 70-88 yr. Frailty was reassessed in 1586 men aged 76-93 yr in 2008-2009.
  
  
  METHODS
  Frailty was assessed with the FRAIL scale, comprising five domains: fatigue, difficulty climbing a flight of stairs, difficulty walking more than 100 m, more than five illnesses present, or weight loss greater than 5%. Testosterone, SHBG, and LH were assayed at baseline. Free testosterone was calculated using mass action equations.
  
  
  RESULTS
  At baseline, 15.2% of men (n = 548) were frail (at least three deficits), increasing to 23.0% (n = 364) at follow-up. At baseline, each 1 sd decrease in total or free testosterone level was associated with increased odds of frailty [odds ratio (OR) = 1.23; 95% confidence interval (CI) = 1.11-1.38, and OR = 1.29; 95% CI = 1.15-1.44 for total and free testosterone, respectively]. Lower LH was associated with reduced odds of frailty (OR = 0.88; 95% CI = 0.81-0.95). Adjustments were made for age, body mass index, smoking, diabetes, social support, and other covariates. At follow-up, only lower free testosterone levels (OR = 1.22; 95% CI = 1.05-1.42) predicted frailty.
  
  
  CONCLUSIONS
  Lower free testosterone was independently associated with frailty at baseline and follow-up. Randomized trials should explore whether testosterone therapy can prevent the development of frailty.
authors.affiliation: Western Australian Centre for Health and Ageing (M570), University of Western Australia, 35 Stirling Highway, Crawley, Western Australia 6009, Australia. zoe@sexologyresearch.org
authors.forename: Zoë
authors.initials: Z
authors.lastname: Hyde
authors.forename: Leon
authors.initials: L
authors.lastname: Flicker
authors.forename: Osvaldo P
authors.initials: OP
authors.lastname: Almeida
authors.forename: Graeme J
authors.initials: GJ
authors.lastname: Hankey
authors.forename: Kieran A
authors.initials: KA
authors.lastname: McCaul
authors.forename: S A Paul
authors.initials: SA
authors.lastname: Chubb
authors.forename: Bu B
authors.initials: BB
authors.lastname: Yeap
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D000375:Aging / Q000502:physiology; D015992:Body Mass Index; D016330:Frail Elderly; D015577:Geriatric Assessment; D006801:Humans; D008297:Male; D053580:Muscle Strength / Q000502:physiology; D004856:Postural Balance / Q000502:physiology; D011446:Prospective Studies; D012044:Regression Analysis; D011795:Surveys and Questionnaires; D013739:Testosterone / Q000097:blood*; D016138:Walking / Q000502:physiology
chemical_list: D013739:Testosterone