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Pubertal timing, hormones, and body composition among adolescent Turkana males
Author(s) -
Campbell Benjamin C.,
Leslie Paul W.,
Little Michael A.,
Campbell Kenneth L.
Publication year - 2005
Publication title -
american journal of physical anthropology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.146
H-Index - 119
eISSN - 1096-8644
pISSN - 0002-9483
DOI - 10.1002/ajpa.20204
Subject(s) - sex hormone binding globulin , testosterone (patch) , hormone , endocrinology , medicine , population , biology , dehydroepiandrosterone , physiology , androgen , environmental health
The Turkana, like other East African pastoral groups, are known for their tall adult stature, achieved despite a blunted growth spurt during adolescence and continued growth into the early 20s. To investigate the hormonal mechanisms associated with the pattern of slow and continued adolescent growth, we collected data on hormonal status, height, weight, and trunk skinfolds and ethnographic self‐reports of testicular maturation in a cross‐sectional sample of 35 nomadic and 37 settled Turkana males aged 14–24. Hormonal determinations included testosterone (T), sex hormone‐binding globulin (SHBG), and dehydroepiandrosterone (DHEA) in blood, in addition to urinary DHEA. Self‐reports of testicular maturation showed no difference between settled and nomadic subpopulations. However, nomadic boys exhibited significantly higher levels of T, DHEA, and SHBG. Of all the hormones, only SHBG showed a significant relationship with age. Multiple regression models show blood T and SHBG to be significant independent predictors of achieved height as well as weight, controlling for age. Our results suggest that onset of puberty is substantially delayed among Turkana males, and that bioavailable T is related to growth in stature during adolescence. We suggest that SHBG acts to mediate the effects of energy availability on adolescent growth in this energetically limited population. Our findings may also have implications for understanding adolescent growth among Homo erectus . Am J Phys Anthropol 2005., © 2005 Wiley‐Liss, Inc.