Changes in salivary cortisol levels in pediatric patients with obstructive sleep apnea syndrome after adenotonsillectomy

Objective: Obstructive sleep apnea syndrome (OSAS) activates the stress response system, including the hypothalamic-pituitary-adrenocortical (HPA) axis. The salivary cortisol, as an index of free circulating cortisol levels, may be used as a measure of HPA axis activity. We examined the change in the salivary cortisol level in pediatric OSAS patients before and after adenotonsillectomy (AT). Methods: Forty-eight subjects from 80 subjects suspicious of having OSAS were diagnosed with OSAS by overnight PSG, 34 of 48 OSAS patients undergoing AT, and 13 of 34 OSAS patients were finally enrolled prospectively for this study. Before and three months after the AT, the saliva was collected at night before PSG (n-sCor) and in the early morning after PSG (m-sCor) for the measurements of the salivary cortisol level. Results: Children in the study population (n= 13) were divided into mild (1≤ AHI <5, n= 5), moderate (5≤ AHI <10, n= 3), and severe (AHI ≥10, n= 5) OSAS groups. The mean preoperative AHI in the children was 14.7, and the mean postoperative AHI was 0.33. The percentage of children with AHI <1 after AT was 92.3%. Postoperative m-sCor, the difference of cortisol level (sub-sCor: m-sCor minus n-sCor), and the ratio of cortisol level (r-sCor: m-sCor/n-sCor) showed significant difference postoperatively. Conclusions: AT was associated with improvements in PSG and subjective symptoms in pediatric OSAS patients. In addition, these improvements were significantly related to normalization of salivary cortisol level after AT. Although further study on salivary cortisol levels needs to be done, the measurement of salivary cortisol level before and after AT may predict the outcome of AT as a treatment of OSAS.