Objective: To investigate the relationship between obstructive sleep apnea (OSA) and the metabolic syndrome, an established cardiovascular risk factor, in middle-aged Chinese subjects.
Design: A prospective cross-sectional study from community-dwelling volunteers.
Subjects: Subjects of either sex between 30 and 60 years old were recruited from the staff in public institutions or visitors to community centers in Hong Kong.
Methods: Demographic and anthropomentric indices, blood pressure and metabolic profile (fasting blood glucose, total cholesterol, low-density lipoprotein-cholesterol, high-density lipoprotein-cholesterol and triglycerides) were measured. Overnight polysomnographic studies were conducted. Presence of obstructive sleep apnea (OSA) was defined as apnea-hypopnea index (AHI)5. Metabolic syndrome was defined by the criteria of the National Cholesterol Education Panel, but using Asian cut-off values for abdominal obesity.
Results: A total of 255 subjects (150 men, 105 women) were studied. Subjects with OSA had five-fold risk of having metabolic syndrome. OSA was associated with the metabolic syndrome or its components, including waist circumference, diastolic blood pressure and fasting glucose, after adjusting for confounding variables. The independent determinants of OSA were age, gender, body mass index (BMI) and the metabolic syndrome.
Conclusion: Among community-based middle-aged Chinese subjects, the metabolic syndrome was independent predictor of OSA.