title: The influence of obesity and obstructive sleep apnea on metabolic hormones.
abstract: BACKGROUND
  Obstructive sleep apnea syndrome (OSAS) is a common disorder characterized by excessive daytime sleepiness and repetitive upper airway obstruction episodes during sleep. Clinically, obesity is a major risk factor for developing OSAS. However, OSAS has been associated with hormonal and metabolic alterations that could predispose patients to obesity. The aim of this study was to investigate the independent role of apneas and obesity on plasma levels of metabolic hormones (adiponectin, ghrelin, and leptin) in patients with OSAS.
  
  
  METHODS
  We have studied patients with OSAS and controls with and without obesity. All patients were male, had an apnea-hypopnea index of 20/h or greater, and were eligible for nasal continuous positive airway pressure (nCPAP) treatment. Patients were considered obese (n = 28) when their BMI was higher than 30 kg/m(2) and non-obese (n = 21) when it was lower than 27 kg/m(2). Non-obese control subjects (n = 20) were non-snorers with a normal cardiorespiratory sleep study, while obese control subjects (n = 10) were recruited from those obese subjects who were visited in our sleep unit and for whom OSAS was excluded by full polysomnography. A single blood sample was obtained from an antecubital vein in all participants after the completion of the nocturnal sleep laboratory recording. Plasma leptin, adiponectin, and ghrelin levels were determined by radioimmunoassay.
  
  
  RESULTS
  The adiponectin, ghrelin, and leptin plasma levels were similar in both patients and controls. There were differences in leptin and adiponectin plasma levels between the obese and non-obese in both patient and control groups. In the case of ghrelin, differences between obese and non-obese subjects were only seen in patients. There were no significant differences in hormone levels between the obese controls and obese patients or between non-obese controls and non-obese patients. After 3 months of nCPAP treatment, adiponectin levels decreased significantly both in obese and non-obese patients, and leptin levels decreased in obese patients. Finally, nCPAP did not reduce ghrelin in either obese or non-obese patients.
  
  
  CONCLUSIONS
  The basal levels of leptin, adiponectin, and ghrelin were mostly associated with obesity. We found that sleep apnea was not a determinant factor in leptin, adiponectin, and ghrelin hormonal levels. Interestingly, nCPAP treatment diminishes leptin in obese OSA patients and adiponectin levels in obese and non-obese patients with OSAS.
authors.affiliation: Respiratory Diseases Research Unit, Hospital Universitari Arnau de Vilanova, IRB Lleida, Lleida, Spain.
authors.forename: Manuel
authors.initials: M
authors.lastname: Sánchez-de-la-Torre
authors.forename: Olga
authors.initials: O
authors.lastname: Mediano
authors.forename: Antonia
authors.initials: A
authors.lastname: Barceló
authors.forename: Javier
authors.initials: J
authors.lastname: Piérola
authors.forename: Monica
authors.initials: M
authors.lastname: de la Peña
authors.forename: Cristina
authors.initials: C
authors.lastname: Esquinas
authors.forename: Angelina
authors.initials: A
authors.lastname: Miro
authors.forename: Joaquin
authors.initials: J
authors.lastname: Durán-Cantolla
authors.forename: Alvar G
authors.initials: AG
authors.lastname: Agustí
authors.forename: Francisco
authors.initials: F
authors.lastname: Capote
authors.forename: Jose Maria
authors.initials: JM
authors.lastname: Marin
authors.forename: Josep Maria
authors.initials: JM
authors.lastname: Montserrat
authors.forename: Francisco
authors.initials: F
authors.lastname: García-Río
authors.forename: Ferran
authors.initials: F
authors.lastname: Barbé
mesh_terms: D052242:Adiponectin / Q000097:blood*; D000328:Adult; D001786:Blood Glucose / Q000378:metabolism; D015992:Body Mass Index; D002784:Cholesterol / Q000097:blood; D008076:Cholesterol, HDL / Q000097:blood; D045422:Continuous Positive Airway Pressure; D054439:Ghrelin / Q000097:blood*; D006801:Humans; D020738:Leptin / Q000097:blood*; D008297:Male; D008875:Middle Aged; D009765:Obesity / Q000097:blood*; D017286:Polysomnography; D011446:Prospective Studies; D012016:Reference Values; D020181:Sleep Apnea, Obstructive / Q000097:blood* / Q000175:diagnosis / Q000628:therapy; D013030:Spain; D013223:Statistics as Topic; D014280:Triglycerides / Q000097:blood
chemical_list: D052242:Adiponectin; D001786:Blood Glucose; D008076:Cholesterol, HDL; D054439:Ghrelin; D020738:Leptin; D014280:Triglycerides; D002784:Cholesterol