title: Obstructive Sleep Apnea and Lipid Abnormalities.
abstract: BACKGROUND
  There has been a great interest in the interaction between obstructive sleep apnea (OSA) and metabolic dysfunction, but there is no consistent data suggesting that OSA is a risk factor for dyslipidemia.
  
  
  OBJECTIVE
  The aim of this cross-sectional study was to evaluate the prevalence of lipid abnormalities in patients suspected of OSA, referred to our sleep laboratory for polysomnography.
  
  
  METHODS
  Two hundred patients referred to our hospital with suspected OSA, and all of them underwent for standard polysomnography. All patients with respiratory disturbance index (RDI) above 15 were diagnosed with OSA. In the morning after 12 hours fasting, the blood sample was collected from all patients. Blood levels of triglycerides, total cholesterol, high-density lipoprotein cholesterol (HDL) and low-density lipoprotein cholesterol (LDL), were determined in all study patients. In the study, both OSA positive and OSA negative patients were divided according to the body mass index (BMI) in two groups. The first group with BMI ≤ 30 kg/m^2 and the second group with BMI > 30 kg/m^2.
  
  
  RESULTS
  OSA positive patients with BMI ≤ 30 kg/m^2 had statistically significant higher levels of triglycerides and total cholesterol, and statistically significant lower level of HDL compared to OSA negative patients with BMI ≤ 30. There were no statistically significant differences in age and LDL levels between these groups. OSA positive patients with BMI > 30 kg/m^2 had higher levels of triglycerides, total cholesterol and LDL and lower levels of HDL versus OSA negative patients with BMI > 30 kg/m^2, but without statistically significant differences.
  
  
  CONCLUSIONS
  OSA and obesity are potent risk factors for dyslipidemias. OSA could play a significant role in worsening of lipid metabolism in non-obese patients. But in obese patients, the extra weight makes the metabolic changes of lipid metabolism, and the role of OSA is not that very important like in non-obese patients.
authors.affiliation: University Clinic of Pulmonology and Allergology, Faculty of Medicine, Ss Cyril and Methodius University of Skopje, Skopje, Republic of Macedonia.
authors.forename: Dimitar
authors.initials: D
authors.lastname: Karkinski
authors.affiliation: Clinical Biochemistry, Faculty of Medicine, Ss Cyril and Methodius University of Skopje, Skopje, Republic of Macedonia.
authors.forename: Oliver
authors.initials: O
authors.lastname: Georgievski
authors.affiliation: University Clinic of Nephrology, Faculty of Medicine, Ss Cyril and Methodius University of Skopje, Skopje, Republic of Macedonia.
authors.forename: Pavlina
authors.initials: P
authors.lastname: Dzekova-Vidimliski
authors.affiliation: Univesity Clinic of Endocrinology, Faculty of Medicine, Ss Cyril and Methodius University of Skopje, Skopje, Republic of Macedonia.
authors.forename: Tatjana
authors.initials: T
authors.lastname: Milenkovic
authors.affiliation: University Clinic of Pulmonology and Allergology, Faculty of Medicine, Ss Cyril and Methodius University of Skopje, Skopje, Republic of Macedonia.
authors.forename: Dejan
authors.initials: D
authors.lastname: Dokic
keywords: body mass index (BMI); obstructive sleep apnea (OSA); plasma lipids