Elevated content of cortisol in hair of patients with severe chronic pain: A novel biomarker for stress

• Published in: Stress (Amsterdam, Netherlands) Vol. 11; no. 6; pp. 483 - 488
• Main Authors: Van Uum, S. H. M., Sauvé, B., Fraser, L. A., Morley-Forster, P., Paul, T. L., Koren, G.
• Format: Journal Article
• Language: English
• Published: England Informa UK Ltd 01.01.2008
• Subjects: Adult; Analgesics, Opioid - therapeutic use; Biomarkers - analysis; Chronic Disease; Female; Hair - chemistry; Humans; Hydrocortisone - analysis; Male; Middle Aged; Pain - diagnosis; Pain - drug therapy; Stress, Psychological - metabolism
• ISSN: 1025-3890; 1607-8888
• DOI: 10.1080/10253890801887388

Hair analysis has been used to reflect long-term systemic exposure to exogenous drugs and toxins. Several studies have demonstrated the feasibility of measuring endogenous steroid hormones, e.g. cortisol, in hair. Recently, a study in macaques showed a significant increase in hair cortisol levels induced by stress. We explored whether hair cortisol levels may be used as a biomarker for long-term stress in humans. Patients with severe chronic pain, aged 18 years or older, receiving opioid treatment for at least one year were recruited. Controls were non-obese (body mass index, BMI < 30 mg/kg2) adults. The Perceived Stress Scale (PSS) questionnaire was used to assess perceived stress over the last 4 weeks. A hair sample was obtained from the vertex posterior. Cortisol was measured using an enzyme-linked immunosorbent assay. We included fifteen patients (nine females and six males) and 39 non-obese control subjects (20 females, 19 males). PSS scores (median and range) were significantly higher in chronic pain patients (24: 12-28) than in controls (12: 3-31)(P < 0.001). Hair cortisol contents (median and range) were significantly greater in chronic pain patients (83.1: 33.0-205 g/mg) than in controls (46.1: 27.2-200 pg/mg) (P < 0.01). We conclude that hair cortisol contents are increased in patients with major chronic stress. Measurement of cortisol levels in hair constitutes a novel biomarker of prolonged stress.