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

Abstract

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 ϭ 0.027) and salivary cortisol suppression postdexamethasone (P ϭ 0.038) were lower, whereas heart rate (P ϭ 0.022) was higher compared with obese controls. After nCPAP therapy, patients showed a reduction in heart rate (P ϭ 0.036) and a greater cortisol suppression after dexamethasone (P ϭ 0.001). No difference in arterial blood pressure (P ϭ 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 ϭ 0.799, P ϭ 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 OBSTRUCTIVE SLEEP APNEA SYNDROME (OSAS) is receiving increased attention because it seems to be associated with a variety of long-term consequences, such as high rates of morbidity and mortality, mostly due to cardiovascular disease (23). Although obesity is the main risk factor for OSAS (39), it has been demonstrated that OSAS may increase the risk for hypertension, myocardial infarction, congestive heart failure, and stroke independently of obesity. Continuous positive airway pressure (CPAP) therapy is the treatment of choice for patients with moderate-to-severe OSAS, since it is highly effective in improving nocturnal hypoxia and sleep fragmentation, enhancing the quality of life and reducing many cardiovascular complications related to OSAS. However, the lack of acceptance and inadequate adherence to CPAP therapy remain the major causes of sleep apnea treatment failure (10,20,21,31,32).The mechanisms proposed to explain the increased cardiovascular disease in obstructive sleep apnea are under assessment. It is speculated that recurrent episodes of upper airway constriction, progressive hypoxemia, and sleep fragmentation may result in neural and metabolic changes, including activation of peripheral sympathetic activity, inflammatory pathways, and hypothalamic-pituitary-adrenal (HPA) axis, impairment of insulin sensitivity, and generation of reactive oxygen species, which could predispose to vascular damage (16,26,27,34).Sympathetic nervous system has been well demonstrated to be activated in sleep ap...

Obstructive sleep apnea syndrome causes a pseudo-Cushing’s state in Japanese obese patients with type 2 diabetes mellitus

“…In agreement with our results, Carneiro, et al showed that a blunted response of cortisol suppression after 0.25 mg DST in obese men with OSAS compared with obese male controls, which were recovered by CPAP therapy [21]. The previous reports including Carneiro's study were that the effect of CPAP therapy for the HPA axis in OSAS patients was examined three months after CPAP therapy [11,[21][22][23].…”

“…The previous reports including Carneiro's study were that the effect of CPAP therapy for the HPA axis in OSAS patients was examined three months after CPAP therapy [11,[21][22][23]. On the other hand we performed 0.5 mg DST for them within a few but not with AHI (p=0.784), BMI (p=0.984), waist circumference (p=0.967), HbA1c (p=0.261), fasting plasma glucose (p=0.420) or HOMA-IR (p=0.500).…”

Effects of obstructive sleep apnea on serum brain-derived neurotrophic factor protein, cortisol, and lipid levels

“…Cortisol is another hormone synthesized in response to conditions such as those in OSA patients [57]. However, serum cortisol concentrations in OSA patients were not statistically different from those in control group.…”

Sleep apnoea and the hypothalamic–pituitary–adrenal axis in men and women: effects of continuous positive airway pressure

“…Given the above limitations, it is no surprise that studies on the effects of continuous positive airway pressure (CPAP) treatment on HPA axis activity have yielded inconsistent findings [8,10,11,[13][14][15][16][17]. In addition, most of the CPAP studies have been confounded by methodological limitations such as lack of a control group at baseline, or a placebo control group, as well as a small sample size.…”