title: Serum levels of gamma-glutamyl transferase are associated with cardiovascular disease in obstructive sleep apnea syndrome.
abstract: OBJECTIVE
  Obstructive sleep apnea syndrome (OSAS) significantly increases the risk of cardiovascular disease (CVD). Gamma-glutamyl transferase (GGT) is a new marker for predicting CVD. The aim of this study was to evaluate the relationship of serum GGT levels with cardiovascular event, severity of OSAS, and polysomnographic parameters in patients with OSAS.
  
  
  METHODS
  This was a retrospective, cross-sectional study conducted between January 2011 and March 2013 (Gaziosmanpasa University, Faculty of Medicine, Tokat, Turkey).
  
  
  METHODS
  We performed a retrospective study. Patients were divided according to their apnea-hypopnea index (AHI) scores into OSAS negative (AHI < 5, Group 1), mild OSAS (AHI: 5-15, Group 2), moderate OSAS (AHI=15.30, Group 3), and severe OSAS (AHI > 30, Group 4) groups. The presence of heart failure, coronary artery disease, or arrhythmia was defined as CVD.
  
  
  RESULTS
  A total of 320 patients, with a mean age of 50.2 (10.8) years, were included in this study. There were 47, 68, 58, and 147 patients in Groups 1, 2, 3, and 4, respectively. Serum GGT levels were significantly different between groups (Group 1: 25.24 [14.95]; Group 2: 28.03 [11.92]; Group 3: 32.82 [18.18], and Group 4: 40.41 [31.90] mg/dL , P < .001). Besides, serum GGT levels were significantly correlated with AHI, oxygen desaturation index, and average and minimum O2 saturation values (P < .05). Serum GGT levels were significantly higher in patients with CVD compared with those without (P < .05). Multiple regression analysis demonstrated that independent predictors of CVD were serum GGT and low-density lipoprotein-cholesterol levels, age, and body mass index in patients with OSAS.
  
  
  CONCLUSIONS
  GGT level is an important predictor for CVD in patients with OSAS. The effectiveness of continuous positive airway pressure therapy on CVD and GGT levels should be investigated.
authors.affiliation: Handan Inonu Koseoglu, Department of Pulmonary Medicine,, Gaziosmanpas University,, Tokat 60100, Turkey, T: +90 356 212 95 00, F: +90 356 213 31 79, handaninonu@gmail.com.
authors.forename: Handan Inonu
authors.initials: HI
authors.lastname: Koseoglu
authors.forename: Fatih
authors.initials: F
authors.lastname: Altunkas
authors.forename: Osman
authors.initials: O
authors.lastname: Demir
authors.forename: Sibel
authors.initials: S
authors.lastname: Doruk
authors.forename: Ilker
authors.initials: I
authors.lastname: Etikan
authors.forename: Ismail
authors.initials: I
authors.lastname: Benli
mesh_terms: D000328:Adult; D015415:Biomarkers / Q000097:blood; D002318:Cardiovascular Diseases / Q000097:blood / Q000209:etiology* / Q000503:physiopathology; D003430:Cross-Sectional Studies; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D010100:Oxygen / Q000378:metabolism; D017286:Polysomnography; D012189:Retrospective Studies; D012307:Risk Factors; D012720:Severity of Illness Index; D020181:Sleep Apnea, Obstructive / Q000097:blood / Q000150:complications* / Q000503:physiopathology; D014421:Turkey; D005723:gamma-Glutamyltransferase / Q000097:blood*
chemical_list: D015415:Biomarkers; D005723:gamma-Glutamyltransferase; D010100:Oxygen