title: Morning-to-afternoon increases in cortisol concentrations for infants and toddlers at child care: age differences and behavioral correlates.
abstract: This study examined salivary cortisol, a stress-sensitive hypothalamic-pituitary-adrenocortical (HPA) axis hormone in 20 infants (12 females; M age = 10.8 months) and 35 toddlers (20 females; M age = 29.7 months) in full-day, center-based child care. Samples were taken at approximately 10:00 a.m. and 4:00 p.m. at child care and at home. At child care, 35% of infants and 71% of toddlers showed a rise in cortisol across the day; at home, 71% of infants and 64% of toddlers showed decreases. Toddlers who played more with peers exhibited lower cortisol. Controlling age, teacher-reported social fearfulness predicted higher afternoon cortisol and larger cortisol increases across the day at child care. This phenomenon may indicate context-specific activation of the HPA axis early in life.
authors.affiliation: Institute of Child Development, University of Minnesota, 55455, USA.
authors.forename: Sarah E
authors.initials: SE
authors.lastname: Watamura
authors.forename: Bonny
authors.initials: B
authors.lastname: Donzella
authors.forename: Jan
authors.initials: J
authors.lastname: Alwin
authors.forename: Megan R
authors.initials: MR
authors.lastname: Gunnar
mesh_terms: D002652:Child Behavior / Q000502:physiology*; D002656:Child Day Care Centers; D002675:Child, Preschool; D002940:Circadian Rhythm; D005260:Female; D006801:Humans; D006854:Hydrocortisone / Q000032:analysis*; D007030:Hypothalamo-Hypophyseal System / Q000502:physiology; D007223:Infant; D018730:Infant Behavior / Q000502:physiology*; D008297:Male; D010913:Pituitary-Adrenal System / Q000502:physiology; D012463:Saliva / Q000737:chemistry; D013315:Stress, Psychological / Q000378:metabolism; D013694:Temperament
chemical_list: D006854:Hydrocortisone