[Epidemiology of sleep apnea syndrome]

Recent epidemiological studies found an extraordinarily high prevalence of sleep-disordered breathing(SDB) in an apparently healthy population in the USA, Australia and Italy. Estimated prevalence for apnea-hypopnea index > or = 5 and > or = 10 were 24-78% and 15-35% for men and 9-55% and 5-20% for women in middle-aged populations. Obesity and craniofacial dysmorphism are two major risk factors to SDB. Apparent racial differences in the prevalence of SDB were found in the USA population and the differences could be explained with racial characteristics in craniofacial features. The lower limit of the prevalence of SDB was estimated with 0.5-2.9% in child populations in North Europe. Clinical significance of SDB in children should be carefully evaluated near future.