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This Article Full Text Full Text (PDF) All Versions of this Article: 295/2/E380    most recent 00780.2007v1 Alert me when this article is cited Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in ISI Web of Science Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Google Scholar Articles by Carneiro, G. Articles by Zanella, M. T. PubMed PubMed Citation Articles by Carneiro, G. Articles by Zanella, M. T.

Effect of continuous positive airway pressure therapy on hypothalamic-pituitary-adrenal axis function and 24-h blood pressure profile in obese men with obstructive sleep apnea syndrome

¹Department of Medicine, Division of Endocrinology; ²Department of Psychobiology, Sleep Disorders Center, Universidade Federal de Sao Paulo; and ³Hospital do Rim e Hipertensão, Fundação Oswaldo Ramos, Sao Paulo, Brazil

Submitted 15 December 2007 ; accepted in final form 30 May 2008

Obstructive sleep apnea syndrome (OSAS) increases the risk of cardiovascular events. Sympathetic nervous system and hypothalamic-pituitary-adrenal (HPA) axis activation may be the mechanism of this relationship. The aim of this study was to evaluate HPA axis and ambulatory blood pressure monitoring in obese men with and without OSAS and to determine whether nasal continuous positive airway pressure therapy (nCPAP) influenced responses. Twenty-four-hour ambulatory blood pressure monitoring and overnight cortisol suppression test with 0.25 mg of dexamethasone were performed in 16 obese men with OSAS and 13 obese men controls. Nine men with severe apnea were reevaluated 3 mo after nCPAP therapy. Body mass index and blood pressure of OSAS patients and obese controls were similar. In OSAS patients, the percentage of fall in systolic blood pressure at night (P = 0.027) and salivary cortisol suppression postdexamethasone (P = 0.038) were lower, whereas heart rate (P = 0.022) was higher compared with obese controls. After nCPAP therapy, patients showed a reduction in heart rate (P = 0.036) and a greater cortisol suppression after dexamethasone (P = 0.001). No difference in arterial blood pressure (P = 0.183) was observed after 3 mo of nCPAP therapy. Improvement in cortisol suppression was positively correlated with an improvement in apnea-hypopnea index during nCPAP therapy (r = 0.799, P = 0.010). In conclusion, men with OSAS present increased postdexamethasone cortisol levels and heart rate, which were recovered by nCPAP.

sleep disorders; low-dose dexamethasone test; ambulatory blood pressure monitoring