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]  n  = 48, AHI ⩾ 1) groups; the OSAS group was subdivided into mild (1 ⩽ AHI  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.