Aug. 1, 2008 -- Suffering from sleep apnea may do more than just spoil a good night's sleep. A new study shows that people with severe sleep apnea may be up to three times more likely to die prematurely, and that risk increases if the sleep disorder is left untreated.
Sleep apnea is a common sleeping disorder that causes frequent pauses in breathing during sleep and is often accompanied by snoring. About 6% of adults in the U.S. suffer from moderate to severe forms of the condition, and 17% have less severe forms.
In the study, researchers followed more than 1,500 adults for 18 years who had been screened for sleep apnea at the start of the study. The results showed that about 19% of those with severe sleep apnea died during the follow-up period compared with only 4% of those without sleep apnea.
Researchers found the risk of premature death increased as the severity of sleep apnea increased, but findings suggested protection from risk of death with proper treatment of sleep apnea, such as the use of continuous positive airway pressure (CPAP) to keep airways open during sleep and prevent pauses in breathing.
When those who used CPAP regularly to treat their sleep apnea were excluded from the analysis, the risk of death was 3.8 times greater for those with for untreated sleep apnea.
"I was surprised by how much the risks increased when we excluded people who reported treatment with CPAP," researcher Terry Young, PhD, professor of epidemiology at the University of Wisconsin-Madison, says in a news release. "Our findings suggest -- but cannot prove -- that people diagnosed with sleep apnea should be treated, and if CPAP is the prescribed treatment, regular use may prevent premature death."
Sleep Apnea Death Risk
In the study, published in Sleep, researchers followed a random sample of 1,522 men and women between the ages of 30 and 60 who participated in the Wisconsin Sleep Cohort Study.
The participants spent one night at a sleep laboratory under observation and were screened for sleep apnea. Those diagnosed with sleep apnea were divided into groups according to the severity of their condition, as defined by the average number of breathing pauses and sleep disruptions during sleep.
During 18 years of follow-up, 80 people died. The overall risk of death during the study period was 3.2 times higher among those with severe sleep apnea compared with those without sleep apnea at baseline, after adjusting for other risk factors such as age, sex, and body mass index.
The link between sleep apnea and heart-related death was especially strong. About 42% of the deaths in people with severe sleep apnea were due to heart disease, and the risk of heart-related death was more than five times higher among those with untreated severe sleep apnea compared with those without sleep apnea.