title: Similar reference intervals for total testosterone in healthy young and elderly men: results from the Odense Androgen Study.
abstract: BACKGROUND
  Ageing in men is associated with changes in levels of sex hormones.
  
  
  OBJECTIVE
  To evaluate differences in sex hormones in young and elderly men and the significance of comorbidity and fat mass on sex hormones in elderly men.
  
  
  METHODS
  Cross-sectional.
  
  
  METHODS
  Seven hundred and eighty-three men aged 20-29 years and 600 men aged 60-74 years randomly recruited from the background population.
  
  
  METHODS
  Sex hormones and sex hormone-binding globulin (SHBG) were measured, and reference intervals were determined in healthy individuals in both groups and in elderly men stratified according to whether they were obese or lean (waist circumference ≥102 cm).
  
  
  RESULTS
  Sex hormones were lower and SHBG higher in elderly men compared with the young cohort. Lower cut-offs for total testosterone (TT) in healthy, young and elderly men were similar [Lower cut-off (95% CI): Young: 11·7 (11·2-12·1) vs elderly: 11·2 (10·3-12·1) nmol/l], but lower and higher cut-offs of bioavailable testosterone (BT) and free testosterone (FT) were higher in young men. Higher levels of androgens were found in healthy elderly men compared with those with a chronic disease or obesity. Androgens were inversely associated with central fat mass (CFM), whereas SHBG was inversely and directly associated with CFM and lower extremity fat mass, respectively, in both young and elderly men.
  
  
  CONCLUSIONS
  Reference intervals for TT were comparable in healthy young and elderly men, but reference intervals for FT and BT were lower in elderly men due to higher levels of SHBG. Androgens and SHBG were lower in elderly men with chronic disease and inversely associated with CFM.
authors.affiliation: Department of Endocrinology, Odense University Hospital, Odense, Denmark. frostnielsen@yahoo.com
authors.forename: M
authors.initials: M
authors.lastname: Frost
authors.forename: K
authors.initials: K
authors.lastname: Wraae
authors.forename: T L
authors.initials: TL
authors.lastname: Nielsen
authors.forename: D M
authors.initials: DM
authors.lastname: Hougaard
authors.forename: K
authors.initials: K
authors.lastname: Brixen
authors.forename: C
authors.initials: C
authors.lastname: Hagen
authors.forename: M
authors.initials: M
authors.lastname: Andersen
mesh_terms: D000328:Adult; D000367:Age Factors; D000368:Aged; D015992:Body Mass Index; D006801:Humans; D008875:Middle Aged; D012738:Sex Hormone-Binding Globulin / Q000378:metabolism; D013739:Testosterone / Q000097:blood*; D055815:Young Adult
chemical_list: D012738:Sex Hormone-Binding Globulin; D013739:Testosterone