Publication Date

12-1-2015

Abstract

Testosterone is hypothesized to mediate life history trade-offs between reproduction and survival in men, promoting mating effort over other forms of investment, which entails energetic and mortality costs. Sexually dimorphic musculature represents one form of somatic investment in mating. Favorable energy availability is posited to promote preferential investment in mating effort through upregulated testosterone production and augmented musculature, whereas nutritional constraint is predicted to downregulate testosterone to facilitate a diminished, thriftier phenotype. Furthermore, life history trajectories influencing mens testosterone levels have important health implications for androgen-sensitive disease. Here, I examine broad features of men's life history and health, and their association with testosterone. Men's reproductive ecology is characterized by distinctive features\u2014sexual division of labor, decreased testosterone, and male provisioning\u2014that may render a fixed relationship between testosterone and muscularity maladaptive. I collected demographic, life history, and anthropometric data from rural Polish men (at the Mogielica Human Ecology Study Site) to examine how variability in men's testosterone levels interacts with marital and parental status, workload, and musculature. Fatherhood jointly predicted decreased testosterone but increased workload, and positively predicted muscle mass and strength measures. Next, longitudinal data were collected from the same community to examine seasonal fluctuation in men's testosterone, workload, and anthropometry. Men had intensified work demands and decreased testosterone during the summer harvest, but also showed concomitant increase in arm circumference, chest and grip strength. Taken together, these data suggest the importance of provisioning and subsistence activities in determining skeletal muscle phenotype. And lastly, androgenic hormones regulates growth and maintenance of the prostate gland, Although animal, clinical, and in vitro studies suggest that elevated testosterone increases prostate cancer risk, epidemiological investigations comparing testosterone levels of cancer cases with controls generally report an equivocal relationship. However, because testosterone levels are highest and most variable during early adulthood, I conducted a meta-analysis of studies reporting testosterone levels for population samples of younger men, in relation to prostate cancer incidence for the larger sampled populations. A positive association emerged between population differences in young men's testosterone levels and prostate cancer disparities among older men, suggesting that testosterone exposure influences prostate cancer risk.'

Keywords

Men's life history, parental investment, testosterone, prostate cancer

Document Type

Dissertation

Language

English

Degree Name

Anthropology

Level of Degree

Doctoral

Department Name

Anthropology

First Committee Member (Chair)

Jane Lancaster, Co- Chair

Second Committee Member

Martin Muller, Co-Chair

Third Committee Member

Martin Muller, Co-Chair

Fourth Committee Member

Grazyna Jasienska

Fifth Committee Member

Hillard Kaplan

Sixth Committee Member

Joe Alcock

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