title: Correlation of salivary cortisol level with obstructive sleep apnea syndrome in pediatric subjects.
abstract: OBJECTIVE
  Obstructive sleep apnea syndrome (OSAS) is associated with stress system activation involving the hypothalamic-pituitary-adrenocortical (HPA) axis. The relationships among salivary cortisol, a measure of the HPA axis, and objective parameters of polysomnography (PSG) and subjective sleep symptoms were examined.
  
  
  METHODS
  Our prospective study enrolled 80 children who had a physical examination, underwent overnight PSG, and completed the Korean version of the modified pediatric Epworth sleepiness scale (KMPESS) and OSA-18 (KOSA-18) questionnaires. Saliva was collected at night before PSG and in the early morning after PSG.
  
  
  RESULTS
  Subjects (N=80) were divided into control (n=32, apnea-hypopnea index [AHI]<1) and OSAS (n=48, AHI > or =1) groups; the OSAS group was subdivided into mild (1< or = AHI < 5) and moderate to severe (AHI > or =5) groups. Although salivary cortisol before PSG (n-sCor) did not show a significant change with OSAS severity, salivary cortisol after PSG (m-sCor) significantly decreased with OSAS severity. This decrease resulted in a salivary cortisol ratio (r-sCor) that was significantly different between the control group and the two OSAS subgroups. The m-sCor and sub-sCor of the total group as well as the m-sCor, sub-sCor, and r-sCor of the OSAS group were negatively related to the oxygen desaturation index (ODI). The m-sCor and r-sCor in the OSAS group also were related to subjective sleep symptoms (quality of life [QOL] by KOSA-18).
  
  
  CONCLUSIONS
  Among the four salivary cortisol parameters, r-sCor was negatively associated with OSAS severity, ODI, and QOL (KOSA-18), which may indicate a chronically stressed HPA axis. These results demonstrate that salivary cortisol may be a useful biomarker of OSAS.
authors.affiliation: Department of Otolaryngology-Head and Neck Surgery, St. Vincent's Hospital, The Catholic University of Korea, College of Medicine, Suwon, Republic of Korea.
authors.forename: Chan-Soon
authors.initials: CS
authors.lastname: Park
authors.forename: Christian
authors.initials: C
authors.lastname: Guilleminault
authors.forename: Se-Hwan
authors.initials: SH
authors.lastname: Hwang
authors.forename: Jong-Hyun
authors.initials: JH
authors.lastname: Jeong
authors.forename: Dong-Sun
authors.initials: DS
authors.lastname: Park
authors.forename: Jae-Hwan
authors.initials: JH
authors.lastname: Maeng
mesh_terms: D000293:Adolescent; D002648:Child; D002675:Child, Preschool; D005260:Female; D006801:Humans; D006854:Hydrocortisone / Q000032:analysis / Q000378:metabolism*; D007030:Hypothalamo-Hypophyseal System / Q000502:physiology; D008297:Male; D010913:Pituitary-Adrenal System / Q000502:physiology; D017286:Polysomnography; D011446:Prospective Studies; D056910:Republic of Korea; D012463:Saliva / Q000737:chemistry / Q000378:metabolism; D020181:Sleep Apnea, Obstructive / Q000378:metabolism* / Q000503:physiopathology*; D013312:Stress, Physiological / Q000502:physiology*; D011795:Surveys and Questionnaires
chemical_list: D006854:Hydrocortisone
keywords: Child; Cortisol; Polysomnography; Saliva; Sleep-disordered breathing; Stress