Assessment of Chronic Stress: Comparison of Hair Biomarkers and Allostatic Load Indices

Abstract

The measurement of long-term stress is challenging and depends on the population under study. New methods, such as hair markers or ALIs (allostatic load indices), hold promise as a means of assessing personal stress levels. These methods are relatively new and there is still a lack of knowledge concerning their validity and reliability. Objective: This preliminary study aims to determine the test-retest reliability of hair hormone levels (progesterone, cortisol, dehydroepiandrosteron) and two different ALIs as well as the comparability of these biomarker sets among themselves and with different psychometric measures. Methods: Psychometric and physiological data were collected from 13 participants (10 f, 3 m; age = 28.2 ± 2.1 yr.) on two consecutive days with an interval of 24 hours. An 18-biomarker ALI included: HbA1c (glycosylated hemoglobin), fasting glucose, insulin resistance, triglycerides, HDL (high-density lipoprotein), LDL (low-density lipoprotein) waist-hip ratio, BMI (body mass index), BPSYS (systolic blood pressure), BPDIA (diastolic blood pressure), resting pulse, DHEA-S (dehydroepiandrosteron-serum), cortisol, epinephrine, norepinephrine (12 h urine), CRP (C-reactive protein), sICAM-1 (soluble intracellular adhesion molecule-1) and e-Selectin. ALI-HPA included only cortisol and DHEA-S. Hair samples (3 cm) were analyzed using high-performance LC-MS/MS (liquid chromatography-mass spectrometry). Subjective stress was documented using TICS (the Trier Inventory of Chronic Stress). Descriptive statistics were quantified as means ± SD and correlations with Pearson’s correlation coefficient. For reliability, ICC (inter-class correlation) 2.1 and Bland-Altman analysis (LoA (limits of agreement) 2.00*SD) were calculated. Results: HCC (Hair cortisol concentrations) and ALIs showed high test-retest reliabilities while other hair hormones (i.e., DHEA, progesterone) were only moderate or good in this respect. ALI and HCC correlated moderately, as did hair DHEA and serum DHEA. Neither HCC and ALI-HPA, nor HCC and 12h-urine cortisol showed significant correlations. Conclusion: HCC and ALIs are reliable techniques for the assessment of chronic stress. Regarding the comparability of the measurement techniques, further studies and larger samples are needed to better understand their cut-off points and predictive power for health risks.