Harvard Women's Health Watch

Severe sleep apnea is linked to cardiovascular death in women

Women with severe obstructive sleep apnea may be at increased risk of dying from a cardiovascular event such as a stroke or heart attack, and treatment with a therapy called continuous positive airway pressure, or CPAP, may reduce that risk. These are the findings of the first study to examine the relationship between obstructive sleep apnea and cardiovascular death exclusively in women. Obstructive sleep apnea causes pauses in breathing during sleep, with symptoms that include snoring and daytime sleepiness. Studies have shown that severe apnea raises the risk of fatal cardiovascular events in men, and that CPAP is protective, but until now, data on women have been lacking. Results were published in the Jan. 17, 2012, issue of Annals of Internal Medicine.

The study. The participants were 1,116 women (average age 57) referred to sleep clinics at two hospitals in Spain between 1998 and 2007. All of the women underwent sleep studies to determine whether they had obstructive sleep apnea. If they did, and if it was sufficiently severe (scoring 30 or higher on a measure called the apnea-hypopnea index, or AHI) or was moderate but accompanied by daytime sleepiness, the women were offered CPAP treatment. CPAP use was tracked by reading a time counter on the device. On the basis of the sleep study and CPAP recommendations, participants were divided into five groups: those without sleep apnea, those with mild to moderate sleep apnea treated with CPAP, those with severe sleep apnea treated with CPAP, those with mild to moderate sleep apnea not treated with CPAP, and those with severe sleep apnea not treated with CPAP. The women were monitored for six years.

The results. After adjusting for various factors, including age, body mass index, and previous cardiovascular events, the researchers found that severe obstructive sleep apnea was associated with an increased risk of death from cardiovascular causes (heart attack, stroke, heart failure, or arrhythmia), and that CPAP reduced this risk. Women with severe obstructive sleep apnea who used CPAP were no more likely to die of cardiovascular causes than women without obstructive sleep apnea. The women with mild to moderate sleep apnea did not have an increased risk of cardiovascular death, whether they were treated with CPAP or not.

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