The present study assessed the modulating effect of education level on cortisol reactivity to the Trier Social Stress Test (TSST) in a sample of 101 middle-aged adults (22 males, 79 females) between the ages of 50 and 65. The TSST involves a public speech and mental arithmetic task in front of an audience. No previous studies have assessed whether education level can have an impact on cortisol reactivity to this psychosocial stressor. It is plausible that greater exposure to academia may impact how one perceives and responds to the demands of the speech and arithmetic task. Should education have an impact on cortisol reactivity to the TSST, future studies will be required to control for this factor in order to reduce both statistical error and false interpretations. In addition to completing the TSST, participants were administered a battery of neurocognitive tests and personality questionnaires, including a report on education level (i.e. number of years total and degree: High School, Junior College, Technical, University). Results showed that adults with post-secondary education above Junior College tended to secrete higher cortisol levels overall, as measured by total area under the curve. However, it was the group with lower educational attainment who showed a greater stress response specific to the TSST, as measured by percentage increase in cortisol from pre- to post-TSST. Analyses also found that higher educated adults performed better than their less educated peers on verbal fluency. Considering that the TSST is an oral task, it is suggested that middle-aged individuals with a lower level of education may find the TSST more stressful due to lower verbal capacity, which may lead to an increased cortisol response to the TSST when compared to individuals with a higher level of education.
It is well known that psychological stress plays an important role in the development of various psychopathologies, including post-traumatic stress disorder, depression, and anxiety (Blake, 2001; McFarlane et al., 2005; Seidler and Wagner, 2006; Shields, 2006). For over a decade now, research has employed challenge tests in order to assess reactive endogenous activity of the hypothalamic–pituitary–adrenal (HPA) axis in order to delineate reactivity to stress in humans.
The Trier Social Stress Test (TSST) is a standardized experimental protocol that allows for the induction of moderate psychological stress in a laboratory setting while recording physiological responses to the stressor (Kirschbaum et al., 1993a). The TSST provides an estimate for the potential of the HPA axis to respond to a given stressor (Kirschbaum et al., 1993a). The protocol consists of an anticipation period and a test period in which participants must deliver a free speech on a given topic and perform a mental arithmetic task in front of an audience (Kirschbaum et al., 1993a). This task has been found to induce a two- to four-fold increase in salivary cortisol levels, a major stress hormone that reflects HPA reactivity (Kirschbaum et al., 1992a and Kirschbaum et al., 1995). This procedure further allows one to compare participants’ stress-reactivity levels, allowing for the assessment of individuals differences (Kirschbaum and Hellhammer, 1994).
To date, a plethora of research has found inter-individual variations in the cortisol response to the TSST. Indeed, factors such as age, gender, nicotine consumption, glucose intake, contraceptive use and menstrual phase induce differences in cortisol reactivity to the TSST (Gonzalez-Bono et al., 2002; Kirschbaum et al., 1992a, Kirschbaum et al., 1992b and Kirschbaum et al., 1993b; Kudielka et al., 2004a).
The role and importance of education level has not been acknowledged in the stress-reactivity literature that utilized the TSST. This may largely be due to the fact that many studies that employ the TSST have done so in a relatively homogenous sample of individuals, such as university students.
Social economic status (SES), which often includes education in its measurement, has been reported as an important factor in health status (Marmot and Shipley, 1996). In terms of stress-reactivity studies, only one study has reported lower stress-reactivity in low SES men, using a stress paradigm that included anger recall, arithmetic, and a cold pressor test (Kristenson et al., 1998). However, not only did this study include a stress paradigm that involved both a psychological and physical stress component, the protocol was carried out in two separate cities, and the samples from each city were compared to one another (i.e. Lituanians compared to Swedish). This type of protocol may call for a number of confounders that are not reported in the study results. Other studies, however, have found no such effect of SES on stress-reactivity in either men or women using various stress paradigms (Adler et al., 2000; Kapuku et al., 2002; Steptoe et al., 2005).
Thus, to this end, it was the goal of the present study to evaluate the influence of education level on stress reactivity to the TSST in a sample of male and female middle-aged adults. Adults between the ages of 50 and 65 are a good sample cohort to investigate the influence of education as variability in education will be higher than that normally tested in the TSST literature (i.e. university students).
