Epidemiology, pathophysiology, and clinical features of obstructive sleep apnea.

The normal cycle of respiration includes a unique balancing force between many upper airway structures that control its dilation and closure. Alteration of this delicate equilibrium, possibly by an increased airflow resistance, can cause various degrees of obstructive sleep apnea (OSA). OSA is now recognized as a major illness, an important cause of medical morbidity and mortality affecting millions of people worldwide, and a major predisposing factor for several systemic conditions, such as hypertension, cardiovascular disease, stroke, diabetes, and even sexual dysfunction. Initial evaluation for possible OSA may be done by dental professionals who can provide guidance for its comprehensive evaluation and management. Because of the complexity of the disease, factors contributing to its development must be identified. Some factors caused by the patient's anatomic structures are slightly easier to rectify, whereas others may relate to the patient's age, sex, habits, or associated illnesses, including obesity. In this article, various epidemiologic, pathophysiologic, and clinical features of OSA are discussed.