An Emerging Risk Factor for Atherosclerosis

Obstructive sleep apnea (OSA) is independently associated with death from cardiovascular dis- eases, including myocardial infarction and stroke. Myocardial infarction and stroke are com- plications of atherosclerosis; therefore, over the last decade investigators have tried to unravel relationships between OSA and atherosclerosis. OSA may accelerate atherosclerosis by exacer- bating key atherogenic risk factors. For instance, OSA is a recognized secondary cause of hyper- tension and may contribute to insulin resistance, diabetes, and dyslipidemia. In addition, clinical data and experimental evidence in animal models suggest that OSA can have direct proatherogenic effects inducing systemic infl ammation, oxidative stress, vascular smooth cell activation, increased adhesion molecule expression, monocyte/lymphocyte activation, increased lipid loading in mac- rophages, lipid peroxidation, and endothelial dysfunction. Several cross-sectional studies have shown consistently that OSA is independently associated with surrogate markers of premature atherosclerosis, most of them in the carotid bed. Moreover, OSA treatment with continuous pos- itive airway pressure may attenuate carotid atherosclerosis, as has been shown in a randomized clinical trial. This review provides an update on the role of OSA in atherogenesis and highlights future perspectives in this important research area.