ROCHESTER, MINNESOTA. Obstructive sleep apnea (temporary cessation of breathing while sleeping) is increasingly being linked to an elevated risk for cardiovascular and cerebrovascular disease (heart disease and stroke). Researchers at the Mayo Clinic believe they have discovered the link between sleep apnea and heart disease. Their clinical trial involved 22 patients (18 males and 4 females) with newly diagnosed sleep apnea and 20 healthy controls. The patients experienced apnea (complete cessation of airflow for at least 10 seconds) an average of 60 times an hour; their lowest average oxygen saturation level recorded during sleep was 79 per cent as compared to 96 per cent during daytime. The researchers found that the patients' average (median) blood plasma CRP (C-reactive protein) levels were over three times higher than that of the controls (0.33 mg/dL versus 0.09 mg/dL). The association between the number of apnea events and CRP level was linear with a patient experiencing 100 events per hour having a CRP level of about 1.0 mg/dL. The researchers believe that interrupted sleep and low oxygen concentrations promote inflammation (high CRP levels) and that this inflammation in turn initiates atherosclerosis eventually leading to heart disease. They suggest that reducing CRP levels in sleep apnea patients by drug treatment may decrease their risk of cardiovascular and cerebrovascular disease.
Shamsuzzaman, Abu S.M., et al. Elevated C-reactive protein in patients with obstructive sleep apnea. Circulation, Vol. 105, May 28, 2002, pp. 246264