1Anthropology, Boston University, 2Psychology, Nipissing University
March 29, 2019 , CC Ballroom BC
Previous studies show a positive relationship between testosterone (T) and secretory immuno-globulin-A (sIgA) when saliva is sampled at a single time point, suggesting that men with relatively higher T levels have higher concentrations of one biomarker of mucosal immunity. The purpose of this investigation was to explore intra-individual associations between secretory sIgA, cortisol (CORT), and T within a single day (i.e. morning vs. evening) and across 2 sequential days. As part of a larger study on health and human mating, 119 young men provided saliva samples at three time points, upon waking and before sleep on the first day and upon waking the following day. Samples were assayed in duplicate for sIgA, T and CORT, and averaged for all analyses. To analyze within- and between-day relationships, we computed difference variables between the log transformed concentrations for all bio-markers for all sample provision times and compared them using Pearson correlations. Changes in T were significantly positively correlated with changes in sIgA. Fluctuation of sIgA and CORT from evening to the following morning were significantly negatively correlated. To analyze the interactive affect that T and CORT may have on sIgA, we multiplied T and CORT concentrations (T*CORT), and again computed difference variables. Changes in T*CORT were also significantly positively correlated with sIgA variation. This provides the first evidence that salivary T and sIgA concentrations are associated within a single day and across sequential days. These results have the potential to add to our understanding of the standard and stress-linked immunocompetence handicap hypotheses.