BACKGROUND: Age-related declines in free and bioavailable testosterone are frequently reported for Western populations, but interpopulation variation in this pattern has not previously been investigated. METHODS: Salivary testosterone was measured using a consistently applied protocol on morning samples collected from men in four populations (USA, Congo, Nepal, and Paraguay) representing different geographical, ecological, and cultural settings. RESULTS: Mean testosterone levels varied significantly between the four populations. The mean testosterone differences between populations were greatest for young men (aged 15-30 years) and insignificant for older men (aged 45-60 years). The slope of age-related decline in testosterone was significant in the USA and Congolese participants, but not in the Nepalese or Paraguayan participants. CONCLUSIONS: Age patterns of testosterone decline vary between populations primarily as a result of variation in the peak levels attained in young adulthood. The potential consequences of this variation for other aspects of male health deserve investigation.
BACKGROUND: Age-related declines in free and bioavailable testosterone are frequently reported for Western populations, but interpopulation variation in this pattern has not previously been investigated. METHODS: Salivary testosterone was measured using a consistently applied protocol on morning samples collected from men in four populations (USA, Congo, Nepal, and Paraguay) representing different geographical, ecological, and cultural settings. RESULTS: Mean testosterone levels varied significantly between the four populations. The mean testosterone differences between populations were greatest for young men (aged 15-30 years) and insignificant for older men (aged 45-60 years). The slope of age-related decline in testosterone was significant in the USA and Congolese participants, but not in the Nepalese or Paraguayan participants. CONCLUSIONS: Age patterns of testosterone decline vary between populations primarily as a result of variation in the peak levels attained in young adulthood. The potential consequences of this variation for other aspects of male health deserve investigation.
Authors: Heini Natri; Angela R Garcia; Kenneth H Buetow; Benjamin C Trumble; Melissa A Wilson Journal: Trends Genet Date: 2019-07 Impact factor: 11.639
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Authors: Benjamin C Trumble; Aaron D Blackwell; Jonathan Stieglitz; Melissa Emery Thompson; Ivan Maldonado Suarez; Hillard Kaplan; Michael Gurven Journal: Am J Phys Anthropol Date: 2016-07-28 Impact factor: 2.868
Authors: C M Schooling; C Q Jiang; T H Lam; B J Cowling; S L Au Yeung; W S Zhang; K K Cheng; G M Leung Journal: BMC Public Health Date: 2010-05-24 Impact factor: 3.295
Authors: Y Kobori; E Koh; K Sugimoto; K Izumi; K Narimoto; Y Maeda; H Konaka; A Mizokami; T Matsushita; T Iwamoto; M Namiki Journal: Int J Impot Res Date: 2009-05-07 Impact factor: 2.896