title: Healthier lifestyle predicts higher circulating testosterone in older men: the Health In Men Study.
abstract: OBJECTIVE
  Circulating testosterone declines during male ageing, and low testosterone may predispose to ill health. We sought to determine whether greater participation in healthy behaviours predicted reduced risk of subsequent lower circulating testosterone in older men.
  
  
  METHODS
  Cross-sectional analysis of a population-based follow-up study.
  
  
  METHODS
  A total of 3453 men aged 65-83 years.
  
  
  METHODS
  Lifestyle score, a tally of eight prudent health-related behaviours, was determined during 1996-99. Early morning sera collected in 2001-04 were assayed for total testosterone, SHBG and LH. Free testosterone was calculated using mass action equations.
  
  
  RESULTS
  Mean (+/- SD) time between collection of lifestyle data and blood sampling was 5.7 +/- 0.9 years. Lifestyle score correlated with subsequent total testosterone (r = 0.06, P < 0.001) and SHBG (r = 0.07, P < 0.001), but not free testosterone (r = 0.03, P = 0.08) or LH (r = -0.03, P = 0.12). In multivariate analyses, higher lifestyle scores (4 and above) predicted reduced risk of total testosterone and SHBG in the lowest quartile of values. For the highest category (>or= 7), odds ratio (95% CI) for total testosterone and SHBG in the lowest quartile were 0.37 (0.18-0.77) and 0.26 (0.13-0.54), respectively. Lower lifestyle scores including and excluding body mass index predicted higher risk of total testosterone and SHBG in the lowest quartiles.
  
  
  CONCLUSIONS
  In men > 65 years old, higher lifestyle score reflecting greater engagement in healthy behaviours predicts higher subsequent total testosterone and SHBG levels. This relationship appears cumulative and may reflect interaction between lifestyle and insulin sensitivity. Successfully promoting healthy behaviours in older men could ameliorate the age-related decline in circulating testosterone.
authors.affiliation: School of Medicine and Pharmacology, University of Western Australia, Fremantle Hospital, Fremantle, Australia. byeap@cyllene.uwa.edu.au
authors.forename: Bu B
authors.initials: BB
authors.lastname: Yeap
authors.forename: Osvaldo P
authors.initials: OP
authors.lastname: Almeida
authors.forename: Zoë
authors.initials: Z
authors.lastname: Hyde
authors.forename: Paul E
authors.initials: PE
authors.lastname: Norman
authors.forename: S A Paul
authors.initials: SA
authors.lastname: Chubb
authors.forename: Konrad
authors.initials: K
authors.lastname: Jamrozik
authors.forename: Graeme J
authors.initials: GJ
authors.lastname: Hankey
authors.forename: Leon
authors.initials: L
authors.lastname: Flicker
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D000375:Aging / Q000097:blood*; D015992:Body Mass Index; D003430:Cross-Sectional Studies; D005500:Follow-Up Studies; D006801:Humans; D008019:Life Style; D016015:Logistic Models; D007986:Luteinizing Hormone / Q000097:blood; D008297:Male; D015999:Multivariate Analysis; D012738:Sex Hormone-Binding Globulin / Q000378:metabolism; D013739:Testosterone / Q000097:blood*
chemical_list: D012738:Sex Hormone-Binding Globulin; D013739:Testosterone; D007986:Luteinizing Hormone