Salivary testosterone and body composition among Ariaal males

Abstract

To determine if testosterone is negatively related to acute and/or chronic nutritional status among men in a subsistence society, saliva samples and anthropometric measures were compared among nomadic and settled Ariaal pastoralists of northern Kenya. Fifty-six nomadic men and 62 settled men facing drought conditions, estimated ages 22-96 years, were sampled. Measures included height, weight, four skinfolds, and %body fat by bioelectric impedance (BIA). Saliva samples were assayed for testosterone using radioimmunoassay. Overall, both body mass index (BMI) (avg. = 17.8 +/- 6.0 kg/m(2)) and salivary testosterone (T) levels (avg. am value = 176.8 +/- 74.8 pmol/l) were low compared to values from Western populations. Comparison of the two subpopulations revealed no significant difference in height, weight, BMI, or lean body mass. However, nomadic males exhibited significantly smaller skinfolds. Evening, but not morning, salivary T values differed between the subpopulations. Age-related changes in body composition included a significant decline in BMI with age, related to loss of body fat, but with little change in lean body mass. Age-related declines in BMI and %body fat were more pronounced among the nomadic males. am salivary T values declined with age; again, the decline was significantly greater among nomadic males. pm salivary T levels showed no significant decline with age. When controlled for residence and age, salivary T was positively related to %body fat and WHR ratio, but not lean body mass. These results provide evidence that salivary T is related to acute nutritional status among males in an energetically stressed subsistence population, in accordance with life history theories of somatic allocation.