OSAS is equally common among the middle-aged male Caucasian and Hong Kong (HK) Chinese populations with prevalence rates of at least 4%. The prevalence and severity of OSAS tend to increase through adult life, peaking in the late fifties to mid sixties, after which it fails to increase or decrease. Another group of investigators reported high prevalence rates of SDB in a group aged 65-95 years of 70% for men and 56% for women, at least double those reported for middle-aged cohorts.