title: Correlation of cortisol in 1-cm hair segment with salivary cortisol in human: hair cortisol as an endogenous biomarker.
abstract: BACKGROUND
  Cortisol level in human hair would be an endogenous biomarker for the retrospective assessment of long-term central hypothalamo-pituitary-adrenal activity. However, no direct evidence supports that blood-related diffusion is a biologically endogenous source of hair cortisol in humans. The present study aims to validate the direct correlation between cortisol in 1-cm hair segments and salivary cortisol in healthy humans.
  
  
  METHODS
  We collected three saliva samples from the same participant at Time 1, Time 2 (1 week later) and Time 3 (2 weeks later), and hair 4 weeks later. Cortisol levels in 1-cm hair segments and saliva were determined with high performance liquid chromatography tandem mass spectrometry.
  
  
  RESULTS
  Salivary cortisol at Time 1 was significantly associated with that at Time 2 (r=0.514, p=0.003), but not with that at Time 3 (r=0.187, p=0.305); and the one at Time 2 was significantly associated with that at Time 3 (r=0.380, p=0.032). Hair cortisol was significantly correlated with salivary cortisol at Time 2 (r=0.389, p<0.05) and average salivary cortisol (r=0.383, p<0.05) from three sampling.
  
  
  CONCLUSIONS
  Our results confirmed that blood-related diffusion mechanism is a biologically endogenous source of hair cortisol.
authors: Key Laboratory of Child Development and Learning Science (Southeast University), Ministry of Education, Research Center of Learning Science, Southeast University, Nanjing, PR China.
authors: Qiaozhen
authors: Q
authors: Xie
authors: Wei
authors: W
authors: Gao
authors: Jifeng
authors: J
authors: Li
authors: Ting
authors: T
authors: Qiao
authors: Jing
authors: J
authors: Jin
authors: Huihua
authors: H
authors: Deng
authors: Zuhong
authors: Z
authors: Lu
mesh_terms: D000328:Adult; D015415:Biomarkers / Q000032:analysis; D002851:Chromatography, High Pressure Liquid; D005260:Female; D006197:Hair / Q000737:chemistry*; D006801:Humans; D006854:Hydrocortisone / Q000032:analysis*; D008297:Male; D012189:Retrospective Studies; D012463:Saliva / Q000737:chemistry*; D053719:Tandem Mass Spectrometry; D055815:Young Adult
chemical_list: D015415:Biomarkers; D006854:Hydrocortisone