title: Correspondence between hair cortisol concentrations and 30-day integrated daily salivary and weekly urinary cortisol measures.
abstract: Characterization of cortisol production, regulation and function is of considerable interest and relevance given its ubiquitous role in virtually all aspects of physiology, health and disease risk. The quantification of cortisol concentration in hair has been proposed as a promising approach for the retrospective assessment of integrated, long-term cortisol production. However, human research is still needed to directly test and validate current assumptions about which aspects of cortisol production and regulation are reflected in hair cortisol concentrations (HCC). Here, we report findings from a validation study in a sample of 17 healthy adults (mean±SD age: 34±8.6 yrs). To determine the extent to which HCC captures cumulative cortisol production, we examined the correspondence of HCC, obtained from the first 1cm scalp-near hair segment, assumed to retrospectively reflect 1-month integrated cortisol secretion, with 30-day average salivary cortisol area-under-the curve (AUC) based on 3 samples collected per day (on awakening, +30min, at bedtime) and the average of 4 weekly 24-h urinary free cortisol (UFC) assessments. To further address which aspects of cortisol production and regulation are best reflected in the HCC measure, we also examined components of the salivary measures that represent: (1) production in response to the challenge of awakening (using the cortisol awakening response [CAR]), and (2) chronobiological regulation of cortisol production (using diurnal slope). Finally, we evaluated the test-retest stability of each cortisol measure. Results indicate that HCC was most strongly associated with the prior 30-day integrated cortisol production measure (average salivary cortisol AUC) (r=0.61, p=0.01). There were no significant associations between HCC and the 30-day summary measures using CAR or diurnal slope. The relationship between 1-month integrated 24-h UFC and HCC did not reach statistical significance (r=0.30, p=0.28). Lastly, of all cortisol measures, test-retest correlations of serial measures were highest for HCC (month-to-month: r=0.84, p<0.001), followed by 24-h UFC (week-to-week: r's between 0.59 and 0.68, ps<0.05) and then integrated salivary cortisol concentrations (week-to-week: r's between 0.38 and 0.61, p's between 0.13 and 0.01). These findings support the contention that HCC provides a reliable estimate of long-term integrated free cortisol production that is aligned with integrated salivary cortisol production measured over a corresponding one-month period.
authors.affiliation: Department of Psychiatry, University of North Carolina at Chapel Hill, NC 27599, USA.
authors.forename: Sarah J
authors.initials: SJ
authors.lastname: Short
authors.affiliation: Department of Psychology, Technische Universität Dresden, 01069, Dresden, Germany.
authors.forename: Tobias
authors.initials: T
authors.lastname: Stalder
authors.affiliation: Brown University, Providence, RI 02912, USA.
authors.forename: Kristine
authors.initials: K
authors.lastname: Marceau
authors.affiliation: Institute for Medical Psychology, Charité Universitätsmedizin Berlin, 10117 Berlin, Germany; Department of Pediatrics, University of California Irvine, Orange, CA 92868, USA.
authors.forename: Sonja
authors.initials: S
authors.lastname: Entringer
authors.affiliation: Institute for Medical Psychology, Charité Universitätsmedizin Berlin, 10117 Berlin, Germany.
authors.forename: Nora K
authors.initials: NK
authors.lastname: Moog
authors.affiliation: Department of Human Development and Family Studies, Iowa State University, Ames, IA 50011, USA.
authors.forename: Elizabeth A
authors.initials: EA
authors.lastname: Shirtcliff
authors.affiliation: Department of Pediatrics, University of California Irvine, Orange, CA 92868, USA; Departments of Psychiatry and Human Behavior, Obstetrics & Gynecology, and Epidemiology, University of California, Irvine, CA 92697, USA.
authors.forename: Pathik D
authors.initials: PD
authors.lastname: Wadhwa
authors.affiliation: Institute for Medical Psychology, Charité Universitätsmedizin Berlin, 10117 Berlin, Germany; Department of Pediatrics, University of California Irvine, Orange, CA 92868, USA. Electronic address: claudia.buss@charite.de.
authors.forename: Claudia
authors.initials: C
authors.lastname: Buss
mesh_terms: D000328:Adult; D001288:Attention; D002940:Circadian Rhythm / Q000502:physiology; D005260:Female; D006197:Hair / Q000737:chemistry; D006801:Humans; D006854:Hydrocortisone / Q000032:analysis* / Q000737:chemistry / Q000652:urine; D008297:Male; D008875:Middle Aged; D012189:Retrospective Studies; D012463:Saliva / Q000737:chemistry
chemical_list: D006854:Hydrocortisone
keywords: Hair cortisol; Methods comparison; Salivary cortisol; Stress; Urinary free cortisol