Obstructive sleep apnoea and cardiovascular morbidity.

Obstructive sleep apnoea (OSA) has been implicated through epidemiologic studies as a co-morbid factor in cardiovascular disease. There is a greater incidence of hypertension and atherosclerosis related diseases such as stroke, angina, and acute myocardial infarction in patients with OSA. However, obesity is a common problem in OSA as well as cardiovascular disease and is argued by some to be the etiologic factor for both OSA and cardiovascular morbidity. Clearly, there is shortened longevity in patients with untreated or inadequately treated OSA. Other factors which could account for this early mortality in OSA are sudden death during sleep (arrhythmia) or even fatalities from sleep related automobile accidents. The reason that the association between OSA and cardiovascular disease remains unclear is that the relationship thus far is demonstrated only by epidemiological association, not by mechanisms showing a cause-effect relationship. Some of these possible mechanisms are discussed below. Regardless of the mechanisms, the evidence is that OSA needs to be treated aggressively if patient morbidity and mortality from cardiovascular disease is to be reduced.