title: Serum testosterone levels correlate with haemoglobin in middle-aged and older men.
abstract: BACKGROUND
  Lower testosterone levels are associated with anaemia in older men and women. The relation between testosterone and haemoglobin (Hb) in younger and middle-aged men is less well defined. The aim of the study was to examine the association between testosterone and Hb levels in men spanning middle to older ages.
  
  
  METHODS
  A cross-sectional analysis of 492 men aged 30.7-94.5 years from the Busselton Health Survey, Western Australia, was carried out. Haemoglobin (Hb), early-morning serum total testosterone and sex hormone-binding globulin (SHBG) were measured. Free testosterone was calculated using mass action equations.
  
  
  RESULTS
  Haemoglobin correlated to total and free testosterone concentrations (r= 0.13, P= 0.003 and r= 0.20, P < 0.001, respectively). Hb and SHBG were inversely correlated (r=-0.14, P= 0.001). Hb increased across lowest to highest quartiles of total testosterone (P= 0.02) and free testosterone (P < 0.001), but not SHBG. After adjusting for age, waist circumference, smoking status, alcohol consumption, renal function and ferritin, total testosterone was associated with Hb (beta= 0.037, P= 0.003) as was free testosterone (beta= 2.32, P < 0.001), whereas SHBG was not associated.
  
  
  CONCLUSIONS
  Testosterone concentration modulates Hb levels in community-dwelling men across a wide age range. Further studies are needed to clarify implications of this association between testosterone and Hb in men.
authors.affiliation: School of Medicine and Pharmacology, University of Western Australia, Perth, Australia.
authors.forename: B B
authors.initials: BB
authors.lastname: Yeap
authors.forename: J
authors.initials: J
authors.lastname: Beilin
authors.forename: Z
authors.initials: Z
authors.lastname: Shi
authors.forename: M W
authors.initials: MW
authors.lastname: Knuiman
authors.forename: J K
authors.initials: JK
authors.lastname: Olynyk
authors.forename: D G
authors.initials: DG
authors.lastname: Bruce
authors.forename: E A
authors.initials: EA
authors.lastname: Milward
mesh_terms: D000328:Adult; D000367:Age Factors; D000368:Aged; D000369:Aged, 80 and over; D000740:Anemia / Q000097:blood / Q000175:diagnosis; D003430:Cross-Sectional Studies; D006454:Hemoglobins / Q000378:metabolism*; D006801:Humans; D007006:Hypogonadism / Q000097:blood / Q000175:diagnosis; D008297:Male; D008875:Middle Aged; D012737:Sex Factors; D012738:Sex Hormone-Binding Globulin / Q000378:metabolism; D013739:Testosterone / Q000097:blood* / Q000502:physiology
chemical_list: D006454:Hemoglobins; D012738:Sex Hormone-Binding Globulin; D013739:Testosterone