Academic examination stress: Effects on salivary cortisol, neuropeptide Y and interleukin-1β

Abstract

Saliva is one of the preferred non-invasive body fluids for biomarker studies. This study aimed to investigate the possible alteration of stress biomarkers of the students before and after the examinations via salivary cortisol, neuropeptide Y (NPY), and Interleukin-1β (IL-1β) levels. Forty-four adults were included in the study and divided into groups of pre-examination (Group I) and post-examination (Group II). Salivary samples were collected between 8 and 9 a.m. before and after the exam, which ended at 5 p.m. by SARSTEDT saliva collection tubes. Participants were asked to soak the swab with saliva and take it out after 1 min. Swabs were kept at room temperature for 15–30 min and centrifuged for 10–15 min at 1500 g. Salivary cortisol (ng/mL), NPY (ng/mL), and IL-1β (pg/mL) levels were analyzed by Enzyme-linked immunosorbent assay (ELISA). The salivary cortisol, NPY and IL-1 β levels were significantly increased in Group II compared to Group I (9.65 ± 4.53, 6.37 ± 4.14, p < 0.019; 32.12 ± 4.69, 27.10 ± 4.71 p < 0.001; 11.69 ± 3.61, 7.20 ± 3.49, p < 0.0003 respectively). The IL-1β levels were positively and significantly correlated with salivary cortisol and NPY levels in Group II (r = 0.642, p = 0.03; r = 0.589, p = 0.004, respectively). Also, IL-1β levels were positively and significantly correlated with salivary NPY levels in Group I (r = 0.430, p = 0.04). These data indicated that acute stress can alter the inflammatory response and increase NPY release, which is positively associated with cortisol.