title: Increased serum levels of advanced glycation end-products is associated with severity of sleep disordered breathing but not insulin sensitivity in non-diabetic men with obstructive sleep apnoea.
abstract: BACKGROUND
  Patients with diabetes mellitus are known to have increased serum levels of advanced glycation end-products (AGEs), and this is also associated with insulin resistance. This study aimed to investigate the relationship between serum AGEs and insulin sensitivity in non-diabetic subjects with obstructive sleep apnoea (OSA).
  
  
  METHODS
  Adult males with no known comorbidities were recruited from the sleep clinic of a university teaching hospital. They underwent overnight in-laboratory polysomnography. Fasting blood was taken to measure serum AGE and plasma glucose levels. Insulin sensitivity was estimated using the short insulin tolerance test.
  
  
  RESULTS
  In total, 105 subjects with a mean age of 43.5 (standard deviation [SD] 9.2)years, mean body mass index of 27.1 (SD 4.0)kg/m(2), and median apnoea-hypopnoea index (AHI) of 17 (interquartile range 5-46) were analysed. Serum AGE levels were significantly higher in subjects with OSA (AHI ≥5), compared with those without OSA (AHI <5) (3.9 [SD 1.2] vs. 3.2 [SD 0.8]μg/ml, respectively; P=0.037) after adjusting for confounders. AGE levels were positively correlated with AHI (r=0.318, P=0.001), but not with insulin sensitivity. AGE levels decreased in subjects with moderate-to-severe OSA who received continuous positive airway pressure (CPAP) treatment for three months (n=18, P=0.017).
  
  
  CONCLUSIONS
  Serum AGE levels correlate with AHI in non-diabetic adult males. This relationship cannot be explained by insulin sensitivity. Supporting the hypothesis of a direct relationship between AHI and AGEs, AGE levels were found to decline with CPAP therapy.
authors.affiliation: University Department of Medicine, Queen Mary Hospital, The University of Hong Kong, Hong Kong, SAR, China.
authors.forename: Jamie C M
authors.initials: JC
authors.lastname: Lam
authors.forename: Kathryn C B
authors.initials: KC
authors.lastname: Tan
authors.forename: Agnes Y K
authors.initials: AY
authors.lastname: Lai
authors.forename: David C L
authors.initials: DC
authors.lastname: Lam
authors.forename: Mary S M
authors.initials: MS
authors.lastname: Ip
mesh_terms: D000328:Adult; D000368:Aged; D001786:Blood Glucose / Q000032:analysis; D045422:Continuous Positive Airway Pressure; D017127:Glycation End Products, Advanced / Q000097:blood*; D006801:Humans; D007333:Insulin Resistance / Q000502:physiology; D008297:Male; D008875:Middle Aged; D017286:Polysomnography; D012720:Severity of Illness Index; D012891:Sleep Apnea Syndromes / Q000097:blood* / Q000503:physiopathology; D020181:Sleep Apnea, Obstructive / Q000097:blood* / Q000503:physiopathology / Q000628:therapy; D055815:Young Adult
chemical_list: D001786:Blood Glucose; D017127:Glycation End Products, Advanced