Moderate to severe obstructive sleep apnea is associated with an increased risk of death from any cause in middle-aged adults, especially men, according to new results from a landmark study supported by the National Heart, Lung, and Blood Institute (NHLBI) of the National Institutes of Health (NIH).
The new findings provide the strongest evidence to date of a link between increased risk of death and sleep apnea, a common disorder in which the upper airway is intermittently narrowed during sleep, causing breathing to be difficult or completely blocked.
Overall, study participants with severe sleep apnea were at a 40 percent increased risk of death compared to those who did not have the breathing condition. The mortality risk was most apparent in men, who were more likely to die from any cause as well as from heart disease if they had severe sleep apnea. In particular, men between the ages of 40 and 70 with severe sleep apnea were twice as likely to die during the study compared to their peers who did not have the condition.
The study is published in the August 18 issue of the open-access journal PLoS Medicine.
Researchers from the Sleep Heart Health Study (SHHS) studied more than 6,000 men and women aged 40 years and older who had no sleep apnea or had mild, moderate, or severe sleep apnea as determined by a standard at-home sleep test at the beginning of the study. After an average of eight years, participants who had severe sleep apnea at enrollment were one and one-half times more likely to die from any cause, regardless of age, gender, race, or weight, or whether they were a current or former smoker or had other medical conditions such as high blood pressure, heart disease, or diabetes.
The results confirm findings from smaller, community-based studies which have suggested increased frequency of death among adults with sleep apnea. SHHS, which was conducted in seven medical centers across the United States, is the largest and most comprehensive prospective multi-center study to date on the risk of cardiovascular disease and other conditions related to sleep apnea. Earlier findings from SHHS have shown that untreated sleep apnea is associated with increased risk of high blood pressure, heart disease, heart failure, and stroke. Other studies have also linked untreated sleep apnea with overweight and obesity, and diabetes. In addition, untreated sleep apnea contributes to excessive daytime sleepiness, which lowers performance in the workplace and at school, and increases the risk of injuries and death from drowsy driving and other accidents.
More than 12 million adult Americans are believed to have sleep apnea, and most are not diagnosed or treated. Treatments to restore regular breathing during sleep include lifestyle changes, mouthpieces, surgery, and breathing devices, such as continuous positive airway pressure, or CPAP.
These treatments appear to help reduce the severity of symptoms such as loud snoring and excessive daytime sleepiness, thereby improving sleep-related quality of life and performance. Randomized clinical trials to test whether treating sleep apnea lowers the risk of death and cardiovascular disease are needed.
- Punjabi et al. Sleep-Disordered Breathing and Mortality: A Prospective Cohort Study. PLoS Medicine, 2009; 6 (8): e1000132 DOI: 10.1371/journal.pmed.1000132
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