title: Testosterone and estradiol among older men.
abstract: BACKGROUND
  Testosterone and estradiol levels decline with age in men. This change may affect multiple clinical outcomes, but there have been few reports of the distribution and correlates of testosterone and estradiol concentrations in elderly men.
  
  
  OBJECTIVE
  The purpose of these studies was to assess sex steroid levels in a large cohort of older men.
  
  
  METHODS
  We conducted a cross-sectional cohort evaluation.
  
  
  METHODS
  Community-dwelling men were studied at six academic medical centers in the United States.
  
  
  METHODS
  The Osteoporotic Fractures in Men Study is a prospective cohort of men aged at least 65 yr. In these studies, a randomly selected stratified subsample of 2623 participants was analyzed.
  
  
  METHODS
  We assessed levels of total and free testosterone and estradiol and SHBG.
  
  
  RESULTS
  Age was inversely associated with free testosterone and free estradiol levels (P for trend = 0.001 for both). Notably, at any age, there was substantial variation in levels of each hormone. Free testosterone levels were lower in men with greater body mass index, lower SHBG, and poorer self-reported health status and in those of Asian race. Free estradiol concentrations were lower in men with lower body mass index and higher SHBG levels. Free estradiol and free testosterone were modestly correlated (r = 0.20; P < 0.001), but at any level of free testosterone, there was considerable variation in free estradiol levels.
  
  
  CONCLUSIONS
  This is the largest cohort of older men in which sex steroid levels are available, and it demonstrates that testosterone and estradiol, and their free fractions, tend to decline with age even among older men. However, substantial variation is also present. The relationships between sex steroid levels and their consequences in aging are likely to be complex.
authors.affiliation: CR113, Oregon Health & Science University, 3181 SW Sam Jackson Park, Portland, Oregon 97239, USA. orwoll@ohsu.edu
authors.forename: Eric
authors.initials: E
authors.lastname: Orwoll
authors.forename: Lori C
authors.initials: LC
authors.lastname: Lambert
authors.forename: Lynn M
authors.initials: LM
authors.lastname: Marshall
authors.forename: Kathy
authors.initials: K
authors.lastname: Phipps
authors.forename: Janet
authors.initials: J
authors.lastname: Blank
authors.forename: Elizabeth
authors.initials: E
authors.lastname: Barrett-Connor
authors.forename: Jane
authors.initials: J
authors.lastname: Cauley
authors.forename: Kris
authors.initials: K
authors.lastname: Ensrud
authors.forename: Steve
authors.initials: S
authors.lastname: Cummings
mesh_terms: D000368:Aged / Q000502:physiology*; D000369:Aged, 80 and over; D001835:Body Weight / Q000502:physiology; D015331:Cohort Studies; D004958:Estradiol / Q000097:blood*; D005006:Ethnicity; D006801:Humans; D008019:Life Style; D008297:Male; D012016:Reference Values; D012738:Sex Hormone-Binding Globulin / Q000378:metabolism; D013739:Testosterone / Q000097:blood*; D014481:United States / Q000453:epidemiology
chemical_list: D012738:Sex Hormone-Binding Globulin; D013739:Testosterone; D004958:Estradiol