Metabolic aspects of the obstructive sleep apnea syndrome (OSAS) and cardiovascular risk

The obstructive sleep apnea syndrome (OSAS) is characterized by collapse of the upper airway during sleep, recurringapneas, intermittent hypoxemia and daytime somnolence. OSAS is often associated with obesity, and its prevalence isexpected to rise due to the obesity epidemics worldwide. OSAS is associated with increased cardiovascular risk which appearsto be normalized by treatment with nasal continuous positive airway pressure (nCPAP) during sleep, suggesting anindependent role of OSAS in accelerating atherosclerosis. Insulin resistance (IR) and the metabolic syndrome (MetS) areoften found in OSAS patients, but the relative role played by OSAS and obesity is still unclear. Both OSAS and MetS mayexert negative synergistic effects on the cardiovascular system through multiple mechanisms (hypoxemia, sleep disruption,activation of the sympathetic nervous system, inflammatory activation). Besides nCPAP treatment, pharmacologicinterventions to treat obesity and the MetS could improve cardiovascular prevention in OSAS.