2019/07/05 by Carolyn R. Hodges‐Simeon, Soubhana Asif, Michael Gurven +2
Medicine · Neuroscience · Psychology · #Evolutionary Psychology and Human Behavior #Hormonal and reproductive studies #Stress Responses and Cortisol
paper · doi:10.1002/ajhb.23284
openalex publication_date 2019/07/05 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/25
Abstract Objectives A core assumption of life history theory and the immunocompetence handicap hypothesis (ICHH) is that testosterone (T) upregulates energetic investment in mating effort at the expense of immunity. This tenet, along with observed positive relationships between estrogens and immunity, may contribute to the higher observed morbidity and mortality of males. In the present study, we examine the association between sex steroid hormones and mucosal immunity as well as sex differences in immunity in a rural Amazonian population of immune‐challenged Bolivian adolescents. Methods Salivary steroid hormones (T [males only] and estradiol [E 2 , females only]), Tsimane‐specific age‐standardized BMI z‐scores, and salivary mucosal immunity (sIgA, secretory IgA) were measured in 89 adolescent males and females. Results Males had significantly higher sIgA levels than females, which may be due to the observed immune‐endocrine associations found in the present study. Controlling for age and phenotypic condition, higher T significantly predicted higher sIgA; whereas higher E 2 was associated with lower sIgA in females. Conclusions Results stood in contrast to common interpretations of the ICHH, that is, that T should be inversely associated with immunity. Findings from the present study support the notion that the endocrine system likely affects immunity in a regulatory fashion, upregulating certain aspects of immunity while downregulating others. An important remaining question is the adaptive reason(s) for sex differences in endocrine‐mediated immuno‐redistribution.