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Pubertal Timing, Hormones and Body Composition among Adolescent Turkana Males

Citation

Campbell, Benjamin C.; Leslie, Paul W.; Little, Michael A.; & Campbell, Kenneth L. (2005). Pubertal Timing, Hormones and Body Composition among Adolescent Turkana Males. American Journal of Physical Anthropology, 128(4), 896-905.

Abstract

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.

URL

http://dx.doi.org/10.1002/ajpa.20204

Reference Type

Journal Article

Year Published

2005

Journal Title

American Journal of Physical Anthropology

Author(s)

Campbell, Benjamin C.
Leslie, Paul W.
Little, Michael A.
Campbell, Kenneth L.