Research Paper Title
Levels of circulating cortisol and cytokines in members of the Canadian Armed Forces: Associations with age, sex and anthropometry.
To assess blood levels of cortisol and cytokines (inflammatory and non-inflammatory) in members of the regular Canadian Armed Forces (CAF), and examine the associations between sex, age and adiposity and circulating levels of cortisol as well as pro- and anti-inflammatory cytokines.
As part of a larger ranging project, 331 blood samples were collected from a representative population of the total CAF, which included officers and non-commissioned women and men from the Air Force, Navy and Army. The blood samples were analyzed for levels of cortisol, C-Reactive Protein, adiponectin and 20 cytokines (that included interleukins, interferons and Tumor Necrosis Factors).
Higher levels of adiponectin were found in women compared to men (median and IQR; 16.71 (7.68-25.32) vs 5.81 (3.52-13.19) µg/ml), and higher levels of IL-18 in men compared to women (89.25 (84.03-94.48) vs 75.91 (69.70-82.13) pg/ml). An association between age and levels of stress and inflammatory cytokines was observed, with CRP, IL-18, IL-2 and adiponectin all increasing with increasing age. However, contrary to trends seen in the general population, cortisol levels decreased with increasing age. Levels of CRP and IL-18 increased with an increase in adiposity, while adiponectin levels decreased. Most importantly, at the entire cohort level, a low detection rate for most of the cytokines was observed with 17 out of 22 cytokines having a detection below 10%.
In this CAF population, although an association between age and inflammatory cytokines was observed, both sex and adiposity had a small impact on levels of cortisol and cytokines.
Tingelstad, H.C., Filion, L.G., Martin, J., Spivock, M., Tang, V., Haman, F. (2017) Levels of circulating cortisol and cytokines in members of the Canadian Armed Forces: Associations with age, sex and anthropometry. Applied Physiology, Nutrition, and Metabolism. doi: 10.1139/apnm-2017-0551. [Epub ahead of print].