title: Cortisol awakening response in infants during the first six postnatal months and its relation to birth outcome.
abstract: BACKGROUND
  The rise of cortisol concentrations after awakening is well documented in adults and children and commonly used as easily accessible marker of hypothalamic-pituitary-adrenal (HPA) reactivity.
  
  
  OBJECTIVE
  The purpose of this study was to demonstrate the existence of a salivary cortisol awakening response (CAR) in infants, and to estimate its association with birth outcome.
  
  
  METHODS
  The study was conducted in the general community.
  
  
  METHODS
  Healthy infants up to six months age (N=64).
  
  
  METHODS
  Mothers were instructed to collect their infant's saliva immediately and 30 min after awakening on two days within 45 days, irrespective of awakening time. Information on birth outcome was collected from medical records and questionnaires.
  
  
  RESULTS
  Linear mixed models analysis revealed a significant rise of infant salivary cortisol concentrations within 30 min after awakening (b=0.128, SE=0.024, t61=5.31, p<0.001), which was quite stable across the two sampling days (r=0.40, p=0.002). The infant CAR was predicted by length of gestation (t58=2.44, p=0.018).
  
  
  CONCLUSIONS
  The current data demonstrate the existence of a CAR in infants as early as during the first six postnatal months; its relationship with length of gestation supports its usefulness for questions related to developmental neuroscience. Therefore, the infant CAR emerges as non-invasive biomarker of HPA axis dynamics at this early stage of life, with relevance for future research and potential clinical applications.
authors.affiliation: Division of Clinical Psychology and Psychiatry, Department of Psychology, University of Basel, Basel, Switzerland.
authors.forename: Marion
authors.initials: M
authors.lastname: Tegethoff
authors.forename: Nicole
authors.initials: N
authors.lastname: Knierzinger
authors.forename: Andrea H
authors.initials: AH
authors.lastname: Meyer
authors.forename: Gunther
authors.initials: G
authors.lastname: Meinlschmidt
mesh_terms: D000328:Adult; D000367:Age Factors; D001143:Arousal / Q000502:physiology*; D002657:Child Development / Q000502:physiology*; D006801:Humans; D006854:Hydrocortisone / Q000032:analysis / Q000378:metabolism*; D007030:Hypothalamo-Hypophyseal System / Q000378:metabolism / Q000502:physiology; D007223:Infant; D007231:Infant, Newborn; D009034:Mother-Child Relations; D036801:Parturition / Q000378:metabolism / Q000502:physiology* / Q000523:psychology; D010913:Pituitary-Adrenal System / Q000378:metabolism / Q000502:physiology; D012463:Saliva / Q000737:chemistry / Q000378:metabolism; D013315:Stress, Psychological / Q000378:metabolism / Q000503:physiopathology; D014851:Wakefulness / Q000502:physiology*; D055815:Young Adult
chemical_list: D006854:Hydrocortisone