Researchers say people with a severe form of sleep apnea are several times more likely to die from any cause than people without it.

The findings come from an 18-year study published in the journal Sleep. They confirm smaller studies that indicated an increased risk of death for people with what's known as sleep-disordered breathing.

For people with apnea, their upper airway narrows or becomes blocked periodically as they sleep. In some cases, breathing can stop for seconds or even a minute. The pauses in breathing prevents adequate amounts of oxygen from entering the bloodstream and disrupts sleep. While people with apnea are often not woken up by it, it moves them from deep to light sleep and can happen hundreds of times a night.

The director of the National Center on Sleep Disorders Research says the condition erodes a person's health over time.