title: Obstructive sleep apnea is associated with impaired glucose metabolism in Han Chinese subjects.
abstract: BACKGROUND
  Increasingly, evidence from population, clinic-based and laboratory studies supports an independent association between obstructive sleep apnea syndrome (OSAS) and an increased risk of type 2 diabetes; however, this observation has yet to be replicated in China and the potential mechanisms that link these two conditions are not clear.
  
  
  METHODS
  A total of 179 Han Chinese subjects were enrolled in this study. All subjects underwent polysomnography, the oral glucose tolerance-insulin releasing test (OGTT-IRT) and serum HbA(1)c measurement. Indexes including homeostasis model assessment-IR (HOMA-IR), Matsuda index, HOMA-β, early phase insulinogenic index (ΔI(30)/ΔG(30)), AUC-I(180) and oral disposition index (DIo) were calculated for the assessment of insulin resistance and pancreatic β-cell function.
  
  
  RESULTS
  Based on OGTT, 25.4%, 44.6% and 54.5% subjects were diagnosed having glucose metabolic disorders respectively in control, mild to moderate and severe OSAS groups (P < 0.05). Serum HbA(1)c levels were highest in subjects with severe OSAS (P < 0.05). In contrast, compared with normal subjects, HOMA-β, ΔI(30)/Δ(G30) and DIO were lower in severe OSAS group (P < 0.05). In stepwise multiple linear regressions, 0-min glucose and HbA(1)c were positively correlated with the percentage of total sleep time below an oxyhemoglobin saturation of 90% (T90) (Beta = 0.215 and 0.368, P < 0.05); 30-min and 60-min glucose was negatively correlated with the lowest SpOO(2) (LSpO(2)) (Beta = -0.214 and -0.241, P < 0.05). HOMA-β and DI(O) were negatively correlated with T90 (Beta = -0.153 and -0.169, P < 0.05) while body mass index (BMI) was the only determinant of HOMA-IR and Matsuda index.
  
  
  CONCLUSIONS
  OSAS is associated with impairment in glucose tolerance and pancreatic β-cell function in Han Chinese subjects while insulin sensitivity is mainly determined by obesity.
authors.affiliation: Department of Respiratory Medicine, Shanghai Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai 200025, China.
authors.forename: Chen-juan
authors.initials: CJ
authors.lastname: Gu
authors.forename: Min
authors.initials: M
authors.lastname: Li
authors.forename: Qing-yun
authors.initials: QY
authors.lastname: Li
authors.forename: Ning
authors.initials: N
authors.lastname: Li
authors.forename: Guo-chao
authors.initials: GC
authors.lastname: Shi
authors.forename: Huan-ying
authors.initials: HY
authors.lastname: Wan
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D005260:Female; D005947:Glucose / Q000378:metabolism*; D005951:Glucose Tolerance Test; D006442:Glycated Hemoglobin / Q000032:analysis; D006801:Humans; D007333:Insulin Resistance; D050417:Insulin-Secreting Cells / Q000502:physiology; D008297:Male; D008875:Middle Aged; D017286:Polysomnography; D020181:Sleep Apnea, Obstructive / Q000378:metabolism*
chemical_list: D005947:Glucose; D006442:Glycated Hemoglobin; C517652:hemoglobin A1c protein, human