title: Insomnia symptoms, objective sleep duration and hypothalamic-pituitary-adrenal activity in children.
abstract: BACKGROUND
  Insomnia symptoms are the most common parent-reported sleep complaints in children; however, little is known about the pathophysiology of childhood insomnia symptoms, including their association with hypothalamic-pituitary-adrenal (HPA) axis activation. The objective of this study is to examine the association between parent-reported insomnia symptoms, objective short sleep duration and cortisol levels in a population-based sample of school-aged children.
  
  
  METHODS
  A sample of 327 children from the Penn State Child Cohort (5-12 years old) underwent 9-h overnight polysomnography and provided evening and morning saliva samples to assay for cortisol. Objective short sleep duration was defined based on the median total sleep time (i.e., <7·7 h). Parent-reported insomnia symptoms of difficulty initiating and/or maintaining sleep were ascertained with the Pediatric Behavior Scale.
  
  
  RESULTS
  Children with parent-reported insomnia symptoms and objective short sleep duration showed significantly increased evening (0·33±0·03 μg/dL) and morning (1·38±0·08 μg/dL) cortisol levels. In contrast, children with parent-reported insomnia symptoms and 'normal' sleep duration showed similar evening and morning cortisol levels (0·23±0·03 μg/dL and 1·13±0·08 μg/dL) compared with controls with 'normal' (0·28±0·02 μg/dL and 1·10±0·04 μg/dL) or short (0·28±0·02 μg/dL and 1·13±0·04 μg/dL) sleep duration.
  
  
  CONCLUSIONS
  Our findings suggest that insomnia symptoms with short sleep duration in children may be related to 24-h basal or responsive physiological hyperarousal. Future studies should explore the association of insomnia symptoms with short sleep duration with physical and mental health morbidity.
authors.affiliation: Sleep Research and Treatment Center, Department of Psychiatry, Pennsylvania State University College of Medicine, Hershey, PA, USA.
authors.forename: Julio
authors.initials: J
authors.lastname: Fernandez-Mendoza
authors.forename: Alexandros N
authors.initials: AN
authors.lastname: Vgontzas
authors.forename: Susan L
authors.initials: SL
authors.lastname: Calhoun
authors.forename: Angeliki
authors.initials: A
authors.lastname: Vgontzas
authors.forename: Marina
authors.initials: M
authors.lastname: Tsaoussoglou
authors.forename: Jordan
authors.initials: J
authors.lastname: Gaines
authors.forename: Duanping
authors.initials: D
authors.lastname: Liao
authors.forename: George P
authors.initials: GP
authors.lastname: Chrousos
authors.forename: Edward O
authors.initials: EO
authors.lastname: Bixler
mesh_terms: D002648:Child; D002675:Child, Preschool; D015331:Cohort Studies; D005260:Female; D006801:Humans; D006854:Hydrocortisone / Q000378:metabolism; D007030:Hypothalamo-Hypophyseal System / Q000502:physiology*; D008297:Male; D010913:Pituitary-Adrenal System / Q000502:physiology*; D017286:Polysomnography; D012463:Saliva / Q000737:chemistry; D007319:Sleep Initiation and Maintenance Disorders / Q000503:physiopathology*
chemical_list: D006854:Hydrocortisone
keywords: Children; cortisol; insomnia symptoms; objective sleep duration