JCLL Lecture: S. Ayele

Use of Hair Cortisol Analysis as a Proxy Measure of HPA Axis Activation during High and Low Stress Periods: A Pilot Study among Female University Students

Presentation of First Thesis Results

Background: First studies in humans have already illustrated the valuable use of hair cortisol analysis for the determination of hypothalamus-pituitary-adrenal (HPA) axis activation over time. The current study aimed to investigate if hair cortisol levels were associated with varying levels of subjective stress during a three-months class and exam period (t1: high stress period) versus a three-months summer vacation (t2: low stress period) among 29 female university students (experimental group) compared to a control group composed of 6 PhD students with no varying stress levels across time.

Methods: A hair sample was collected from each study participant after the 6 months period and divided into two 3.3cm segments, reflecting cortisol accumulation in hair during the first versus second measurement period. Subjective stress during both time periods was retrospectively determined after the 6 months period using the Short Trier Inventory for Chronic Stress (STICS).

Results: As expected, no significant variation in subjective stress levels nor hair cortisol levels between t1 and t2 was found for the control group while the experimental group reported significantly higher subjective stress with regard to excessive demands (p<.001, η2=.61) and social conflicts (p=.046, η2=.12) during t1 compared to t2. However, as in the control group, hair cortisol concentrations did not differ between t1 and t2 in the experimental group. Also, subjective stress was unrelated to hair cortisol concentrations.

Conclusion: Although subjective stress was, as expected, higher during the class and examination period than during summer vacation in the experimental group, hair cortisol levels were not associated with varying levels of perceived stress. These preliminary results do not appear to support the idea of hair cortisol levels reflecting changes in subjective stress experience over time among female university students.

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