title: Sex differences of continuous positive airway pressure treatment on flow-mediated dilation in patients with obstructive sleep apnea syndrome.
abstract: BACKGROUND
  There is growing research evidence suggesting the presence of endothelial dysfunction and systemic inflammation in patients with obstructive sleep apnea syndrome (OSAS). Continuous positive airway pressure (CPAP) is the most effective method for treating OSAS; nonetheless, the effects of CPAP on the aforementioned pathophysiologic pathways as well as on the systemic disease that result or coexist with the OSAS remain elusive.
  
  
  OBJECTIVE
  To assess the effect of 3-month CPAP therapy on endothelial-dependent dilation, plasma levels of inflammatory markers, blood pressure (BP), and glucose control on male and female patients with OSAS.
  
  
  METHODS
  Our study group consisted of 40 (24 males and 16 females) patients with no prior history of cardiovascular disease, with an apnea-hypopnea index ≥15, who were assigned to receive CPAP treatment. Measurements of flow-mediated dilation (FMD), 24-hour ambulatory BP, and blood analysis were performed at baseline and 3 months after CPAP therapy.
  
  
  RESULTS
  Baseline FMD values were negatively correlated with the apnea-hypopnea index (r=-0.55, P=0.001). After 3 months of CPAP, there was an increase in the FMD values (5.40%±2.91% vs 3.13%±3.15%, P<0.05) and a significant reduction in the patients' 24-hour systolic BP (122.82±11.88 mmHg vs 130.24±16.75 mmHg, P<0.05), diastolic BP (75.44±9.14 mmHg vs 79.68±11.09 mmHg, P<0.05), and pulse pressure (47.38±9.77 mmHg vs 52.72±11.38 mmHg, P<0.05); daytime systolic BP (125.76±12.69 mmHg vs 132.55±17.00 mmHg, P<0.05) and diastolic BP (77.88±10.39 mmHg vs 82.25±11.01 mmHg, P<0.05); nighttime systolic BP (118.17±13.16 mmHg vs 126.22±17.42 mmHg, P<0.05) and pulse pressure (46.61±10.76 mmHg vs 52.66±11.86 mmHg, P<0.05); and C-reactive protein and HbA1c levels (0.40 [0.40-0.70] mg/L vs 0.60 [0.40-0.84] mg/L and 5.45%±0.70% vs 5.95%±1.08%, respectively; P<0.05). When divided by sex, only male patients produced similar statistically significant results, while female patients failed to show such associations.
  
  
  CONCLUSIONS
  Our results suggest that CPAP therapy improves the endothelial function, the BP, and the glucose control in male patients with OSAS. Further research is warranted in order to verify these results and to further elucidate the impact of CPAP on the cardiovascular risk of male and female patients with OSAS.
authors: Sleep Disorders Unit, Department of Clinical Therapeutics, "Alexandra" General Hospital, Athens School of Medicine, Athens, Greece.
authors: Anastasios
authors: A
authors: Kallianos
authors: Sleep Disorders Unit, Department of Clinical Therapeutics, "Alexandra" General Hospital, Athens School of Medicine, Athens, Greece.
authors: Athanasios
authors: A
authors: Panoutsopoulos
authors: Sleep Disorders Unit, Pulmonary Department, 401 General Army Hospital, Athens, Greece.
authors: Christoforos
authors: C
authors: Mermigkis
authors: Sleep Disorders Unit, Department of Clinical Therapeutics, "Alexandra" General Hospital, Athens School of Medicine, Athens, Greece.
authors: Konstantinos
authors: K
authors: Kostopoulos
authors: Sleep Disorders Unit, Department of Clinical Therapeutics, "Alexandra" General Hospital, Athens School of Medicine, Athens, Greece.
authors: Chrysanthi
authors: C
authors: Papamichail
authors: Pulmonary Department, 251 Hellenic Air Force General Hospital, Athens, Greece.
authors: Ioannis
authors: I
authors: Kokkonouzis
authors: Sleep Disorders Unit, Department of Clinical Therapeutics, "Alexandra" General Hospital, Athens School of Medicine, Athens, Greece.
authors: Christoforos
authors: C
authors: Kostopoulos
authors: Sleep Disorders Unit, "Sotiria" Regional Chest Diseases Hospital of Athens, Athens, Greece.
authors: Ioannis
authors: I
authors: Nikolopoulos
authors: Pulmonary Department - Oncology Unit, George Papanikolaou General Hospital of Thessaloniki, Aristotle University of Thessaloniki, Thessaloniki, Greece.
authors: Antonis
authors: A
authors: Papaiwannou
authors: Pulmonary Department - Oncology Unit, George Papanikolaou General Hospital of Thessaloniki, Aristotle University of Thessaloniki, Thessaloniki, Greece.
authors: Sofia
authors: S
authors: Lampaki
authors: Pulmonary Department - Oncology Unit, George Papanikolaou General Hospital of Thessaloniki, Aristotle University of Thessaloniki, Thessaloniki, Greece.
authors: John
authors: J
authors: Organtzis
authors: Pulmonary Department - Oncology Unit, George Papanikolaou General Hospital of Thessaloniki, Aristotle University of Thessaloniki, Thessaloniki, Greece.
authors: Georgia
authors: G
authors: Pitsiou
authors: Pulmonary Department - Oncology Unit, George Papanikolaou General Hospital of Thessaloniki, Aristotle University of Thessaloniki, Thessaloniki, Greece.
authors: Paul
authors: P
authors: Zarogoulidis
authors: Sleep Disorders Unit, Department of Clinical Therapeutics, "Alexandra" General Hospital, Athens School of Medicine, Athens, Greece.
authors: Georgia
authors: G
authors: Trakada
mesh_terms: D000328:Adult; D000368:Aged; D001794:Blood Pressure; D002097:C-Reactive Protein; D045422:Continuous Positive Airway Pressure / Q000379:methods*; D004730:Endothelium, Vascular / Q000503:physiopathology*; D005260:Female; D006442:Glycated Hemoglobin; D006801:Humans; D007249:Inflammation / Q000503:physiopathology; D018836:Inflammation Mediators / Q000378:metabolism*; D008297:Male; D008875:Middle Aged; D012307:Risk Factors; D012727:Sex Characteristics; D020181:Sleep Apnea, Obstructive / Q000503:physiopathology* / Q000628:therapy*
chemical_list: D002097:C-Reactive Protein; D006442:Glycated Hemoglobin; D018836:Inflammation Mediators
keywords: CPAP; CRP; blood pressure; glucose control; obstructive sleep apnea syndrome