Sleep-disordered breathing and stroke

Does sleep-disordered breathing cause stroke, or does stroke cause sleep-disordered breathing? Is sleep-disordered breathing an independent risk factor for the development of stroke in the setting of confounding overlapping risk factors, or is the association with stroke mediated by higher levels of cardiovascular risk factors in patients with sleep-disordered breathing? Does the presence of sleep-disordered breathing influence the morbidity or mortality from stroke? Does treatment of sleep-disordered breathing influence this risk? This article explores these questions by critically reviewing the current literature. Epidemiologic studies about the relationship between sleep-disordered breathing and stroke are analyzed regarding the strength of the association, temporal relationship, dose-response relationship, and consistency of the association using different study designs and different populations. The biologic plausibility of the relationship is explored by reviewing studies that examine the pathophysiology of sleep-disordered breathing and stroke focusing on cerebral hemodynamic and humoral mechanisms.