Association of obstructive sleep apnea and glucose metabolism in subjects with or without obesity

Objective-The purpose of this study was to investigate whether the impact of obstructive sleep apnea (OSA) on glucose metabolism was different according to the presence or absence of obesity. Research design and methods-A total of 1,344 subjects >40 years old from the Korean Genome and Epidemiology Study were included. OSA was detected by home portable sleep monitoring. Plasma glucose, HbA_1c, and insulin resistance were compared according to OSA and obesity status. The associations between OSA and impaired fasting glucose (IFG), impaired glucose tolerance (IGT), IFG + IGT, and diabetes were evaluated in subjects with and without obesity after adjusting for several confounding variables. The effect of visceral obesity on this association was evaluated in 820 subjects who underwent abdominal computed tomography scanning. Results-In subjects without obesity, fasting glucose, 2-h glucose after 75-g glucose loading, and HbA_1c were higher in those with OSA than in those without after controlling for age, sex, and BMI. In addition, the presence of OSA in nonobese subjects was associated with a higher prevalence of IFG + IGT and diabetes after adjusting for several confounding variables (odds ratio 3.15 [95% CI 1.44-6.90] and 2.24 [1.43-3.50] for IFG + IGT and diabetes, respectively). Further adjustment for visceral fat area did notmodify this association. In contrast, in those with obesity, none of the abnormal glucose tolerance categories were associated with OSA. Conclusions-The presence of OSA in nonobese individuals is significantly associated with impaired glucose metabolism, which can be responsible for future risk for diabetes and cardiovascular disease.