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."