Prevalence of obstructive sleep apnea in Asian adults: a systematic review of the literature

Background: Obstructive sleep apnea (OSA) is a common disease, affecting approximately 2% of women and 4% of men residing in Western communities. No systematically reviewed data are available about the prevalence of this disease in Asia, the most heavily populated continent. Methods: PubMed/Medline, Scopus and Google Scholar were searched for articles published from 1993 to May 2012 that reported the prevalence of OSA diagnosed via sleep monitoring and the prevalence of patients at risk for OSA as assessed by symptomatology and/or sleep questionnaires. We have also searched abstract database of major pulmonary and sleep scientific societies for relevant abstracts presented from 2010 to 2012. The following inclusion criteria were used: articles published in English, age >= 18 years, >= 100 participants in studies using sleep monitoring for the diagnosis of OSA, >= 300 participants in studies using questionnaires to detect patients at high risk for OSA. Exclusion criteria: duplicate publications, studies reporting the prevalence of central sleep apnea only, hospital based studies as well as studies assessing OSA prevalence among patients with resistant arterial hypertension, chronic kidney disease, heart failure and in patients with concomitant neurological disease. Results: Twenty four articles were found to meet the inclusion criteria, covering 47,957 subjects (26,042 men and 21,915 women) and four relevant abstracts were noted. OSA prevalence ranged from 3.7% to 97.3%. Male gender, older age, a higher BMI and waist to hip ratio, greater neck circumference, arterial hypertension, smoking, snoring and daytime sleepiness were associated with OSA. Sample size, difference between the populations studied and the fact that some works included patients with a high pre test probability of OSA explain the difference in prevalence rates. Conclusion: This systematic review highlights the lack of data regarding the prevalence of OSA in Asians. Only a few studies provide an approximate estimate of the OSA burden in some Asian communities.