To help clarify their relationship to each other and to age, testosterone (T), free testosterone concentration (FTC), androstenedione (A) and sex hormone binding globulin (SHBG) were assayed in healthy, active, community-dwelling male volunteers aged 20-88 years. Standard linear and median regressions revealed mildly significant differences with age in T, whereas FTC decreased markedly, in association with an increase in SHBG. A’s pattern of age differences contrasted with that of T and FTC, exhibiting a decline from ages 20-50, tending to level off thereafter, a pattern which may reflect selection of survivors. The results for T and FTC are compared with those of other researchers; variability within studies of androgen levels in aged males may result from factors associated with subject selection, i.e., health status, physical fitness, sexual activity or other behavioral characteristics.
Purifoy, Frances E.; Koopmans, Lambert H.; and Mayes, Darrel M.
"Age Differences in Serum Androgen Levels in Normal Adult Males,"
4, Article 4.
Available at: https://digitalcommons.wayne.edu/humbiol/vol53/iss4/4