title: Hair-Normalized Cortisol Waking Response as a Novel Biomarker of Hypothalamic-Pituitary-Adrenal Axis Activity following Acute Trauma: A Proof-of-Concept Study with Pilot Results.
abstract: The mechanisms underlying the development of persistent posttraumatic pain and disability remain elusive. Recent evidence suggests that disordered stress-system pathway (hypothalamic-pituitary-adrenal axis) activity may be responsible for the genesis and maintenance of long-term sensory and emotional problems. However, confidence in current evidence is limited by the necessarily retrospective collection of data. Hair cortisol can serve as a calendar of HPA axis activity going back several months prior to injury. The purposes of this pilot study were to determine the feasibility of using hair cortisol and hair-normalized salivary cortisol as biomarkers of distress following traumatic injuries of whiplash or distal radius fracture. Ten subjects provided complete data within 3 weeks of injury. Hair cortisol, cortisol waking response (CWR), and mean daily cortisol (MDC) were captured at inception, as were self-report indicators of pain, disability, and pain catastrophizing. Pain and disability were also captured 3 months after injury. Results indicate that cortisol waking response may be a useful biomarker of current distress as measured using the pain catastrophizing scale, especially when normalized to 3-month hair cortisol (r = 0.77 raw, 0.93 normalized). Hair-normalized CWR may also have predictive capacity, correlating with 3-month self-reported disability at r = 0.70. While promising, the results must be viewed in light of the small sample.
authors.affiliation: School of Physical Therapy, Western University, London, ON, Canada N6G 1H1.
authors.forename: David M
authors.initials: DM
authors.lastname: Walton
authors.affiliation: School of Physical Therapy, McMaster University, Hamilton, ON, Canada L8S 1C7.
authors.forename: Joy C
authors.initials: JC
authors.lastname: Macdermid
authors.affiliation: Department of Physiology and Pharmacology, Western University, London, ON, Canada N6A 5C1.
authors.forename: Evan
authors.initials: E
authors.lastname: Russell
authors.affiliation: Department of Physiology and Pharmacology, Western University, London, ON, Canada N6A 5C1 ; Ivey Chair in Molecular Toxicology, Western University, London, ON, Canada N6A 5C1 ; Department of Pharmacology/Toxicology, Hospital for Sick Children, Toronto, ON, Canada M5G 1X8.
authors.forename: Gideon
authors.initials: G
authors.lastname: Koren
authors.affiliation: Department of Medicine, Schulich School of Medicine and Dentistry, Western University, London, ON, Canada N6A 5C1.
authors.forename: Stan
authors.initials: S
authors.lastname: Van Uum