A community study of sleep-disordered breathing in middle-aged Chinese men in Hong Kong

Abstract

Background: Sleep-disordered breathing (SDB) in Asian populations is being increasingly recognized. This study investigated the prevalence of SDB in Chinese middle-aged office-based male workers in Hong Kong. Methods: Sleep questionnaires were distributed to 1,542 men (age range, 30 to 60 years), and 784 questionnaires were returned. Subsequently, full polysomnographic (PSG) examinations were conducted in 153 questionnaire respondents. Subjects with an apnea-hypopnea index (AMI) ≥ 5 were recalled for clinical assessment. Results: Questionnaire respondents were similar in age and body mass index (BMI) to the general community in the target age range and gender. Habitual snoring was reported by 23% of this cohort and was associated with excessive daytime sleepiness (EDS), hypertension, witnessed abnormal breathing pattern, BMI, and leg movements during sleep. Allowing for subject bias in undergoing PSG, the estimated prevalence of SDB and obstructive sleep apnea syndrome (OSAS) (defined as SDB in the presence of EDS) at various AMI cutoff threshold values was 8.8% and 4.1% (AMI ≥ 5), 6.3% and 3.2% (AHI ≥ 10), and 5.3% and 3.1% (AHI ≥ 15). Multiple stepwise logistic regression analysis identified BMI, habitual snoring, time taken to fall asleep, and age as predictors of SDB at AMI ≥ 5. Analysis of anthropometric parameters indicated that the relative risk of OSAS attributable to obesity was less than in white subjects. Conclusion: This community-based study of sleep apnea among middle-aged men in Hong Kong using full PSG demonstrated an estimated prevalence of OSAS (AHI ≥ 5 and EDS) at 4.1%. Increasing BMI and age were associated with SDB, although factors other than adiposity may also have an important pathogenic role in OSA in Chinese subjects.