title: Effects of nasal CPAP treatment on insulin resistance, lipid profile, and plasma leptin in sleep apnea.
abstract: BACKGROUND
  Obstructive sleep apnea has been linked with metabolic syndrome characterized by dyslipidemia, dyscoagulation, hypertension, and diabetes mellitus type 2 and their cardiovascular consequences. This study was designed to determine the effects of 8 weeks of therapy with continuous positive airway pressure (CPAP) on insulin resistance, glucose, and lipid profile, and the relationship between leptin and insulin-resistance parameters in patients with moderate-to-severe obstructive sleep apnea.
  
  
  METHODS
  In 44 patients, serum cholesterol, triglycerides, high-density lipoprotein, low-density lipoprotein, very low-density lipoprotein, leptin, and insulin parameters were measured at baseline and after 8 weeks of CPAP. Insulin resistance index was based on the homeostasis model assessment (HOMA-IR) method. Insulin sensitivity (HOMA-S) and insulin secretion capacity (HOMA-beta) also were calculated. Thirteen patients were excluded from statistical analyses due to noncompliant CPAP usage (<4 h night(-1)).
  
  
  RESULTS
  In 31 patients who used CPAP for > or =4 h night(-1), CPAP therapy reduced total cholesterol (P < 0.05), low-density lipoprotein (P < 0.05), and leptin (P < 0.05). Circulating leptin levels showed significant correlation with both HOMA-S and HOMA-IR at baseline and follow-up (P = 0.03 for all). In addition, there was no correlation between HOMA-IR and the severity of sleep apnea, which was shown by apnea-hypopnea index.
  
  
  CONCLUSIONS
  In patients with moderate-to-severe obstructive sleep apnea, compliant CPAP usage may improve insulin secretion capacity, reduce leptin, total cholesterol, and low-density lipoprotein levels. Leptin showed significant relationship with insulin resistance, and this relationship remained after 8 weeks of CPAP therapy.
authors.affiliation: Department of Chest Diseases, Istanbul Faculty of Medicine, Istanbul University, Göğüs Hastaliklari Anabilim Dali, Istanbul, Turkey. cuhad@turk.net
authors.forename: Cağlar
authors.initials: C
authors.lastname: Cuhadaroğlu
authors.forename: Ayfer
authors.initials: A
authors.lastname: Utkusavaş
authors.forename: Levent
authors.initials: L
authors.lastname: Oztürk
authors.forename: Serpil
authors.initials: S
authors.lastname: Salman
authors.forename: Turhan
authors.initials: T
authors.lastname: Ece
mesh_terms: D000328:Adult; D000368:Aged; D015415:Biomarkers / Q000097:blood; D001786:Blood Glucose / Q000378:metabolism; D045422:Continuous Positive Airway Pressure; D005260:Female; D006801:Humans; D007328:Insulin / Q000097:blood; D007333:Insulin Resistance; D020738:Leptin / Q000097:blood*; D008055:Lipids / Q000097:blood*; D008297:Male; D024821:Metabolic Syndrome / Q000097:blood / Q000209:etiology / Q000503:physiopathology / Q000517:prevention & control; D008875:Middle Aged; D010349:Patient Compliance; D012720:Severity of Illness Index; D012891:Sleep Apnea Syndromes / Q000097:blood / Q000150:complications / Q000503:physiopathology / Q000628:therapy*; D013997:Time Factors; D016896:Treatment Outcome
chemical_list: D015415:Biomarkers; D001786:Blood Glucose; D007328:Insulin; D020738:Leptin; D008055:Lipids