Epidemiology and natural history of obstructive sleep apnea.

The currently available data suggest that sleep apnea occurs commonly. Prevalence, however, varies markedly according to definitions utilized to characterize the disorder and the population studied; and has been reported to range from 1% (in an industrial working Israeli population) to 42% (in an elderly nursing home population). The degree to which sleep apnea contributes to the pathogenesis of other diseases is not entirely clear. Data from a number of sources suggest that sleep apnea may increase vascular morbidity and that excess mortality may occur in untreated patients. However, the degree to which mortality and morbidity may be influenced by more aggressive treatment of subjects with sleep apnea is not known. In particular, there is a need to better distinguish "clinically" significant sleep apnea from levels of apnea that may have few acute or chronic effects, and to define which segments of the population are at greatest risk for such adverse outcomes.