Naresh Punjabi of Johns Hopkins University in Baltimore, and colleagues, conducted a study that found that people who are afflicted with severe breathing disorders during sleep have a greater likelihood of dying from various causes when compared with people who do not have sleep disorders. The risk is most apparent among men between the ages of 40 to 70 years. The study was recently published in the open access journal Public Library of Science Medicine.

Sleep apnea causes a person to stop breathing repeatedly during their sleep—often for as long as a minute or more, and up to hundreds of times during the night. Of the three types of apnea that include obstructive, central, and mixed, the most common type is obstructive. Obstructive sleep apnea (OSA) is caused by a blockage of the airway, such as occurs when the soft tissue located in the back of the throat collapses and closes during sleep. With central sleep apnea, the brain fails to signal muscles to breathe, and mixed apnea is a combination of the two problems. Although the brain will arouse a person who experiences an apnea event to get them to resume breathing, the sleep disruption causes poor sleep quality. The most common remedy for sleep apnea, Continuous Airway Pressure Therapy (CPAP), utilizes a mask is placed over the face and a person breathes through a tube that pushes air at a constant pressure, preventing patients from stopping breathing from their airway being restricted, allowing them a more peaceful night’s rest. (See image.)

According to the National Institutes of Health, sleep apnea is a very common condition that affects over 12 million Americans. It is estimated that about 24 percent of American men, as well as 9 percent of women, experience irregular breathing patterns during sleep, and most remain unaware of the problem. Common risk factors include being male, overweight, and over the age of forty. Sleep apnea can lead to memory problems, weight gain, impotency, and headaches, as well as may cause high blood pressure or other cardiovascular disease.

The study conducted by Punjabi’s team involved at total of 6,441 men and women between the ages of 40 and 70 who were participants in the Sleep Heart Health Study. During the 8 years of follow-up, the degree of sleep apnea among the participants ranged from none to mild to severe. Almost half of the men in the study (42.9 percent) did not encounter sleep-disordered breathing, while 33.2 percent suffered only a mild breathing disturbance, and 15.7 percent experienced moderate breathing difficulties. However, 8.2 percent had severe sleep apnea. About 25 percent of the women had mild breathing disturbances, while 8 percent had moderate occurrences of breathing difficulties, and 3 percent were severely afflicted by the disorder.

Findings revealed that experiencing as little as 11 minutes of severe, oxygen depriving, sleep apnea on a nightly basis nearly doubled the death rate among men, as severe sleep apnea episodes can cause the blood oxygen level to drop below 90 percent. The researchers used the apnea-hypopnea index (AHI) to measure sleep disruptions and monitor blood oxygen levels of the study participants. Breathing during sleep is severely disrupted when the AHI index is 30 or above, while hypopnea is abnormally shallow breathing.

A total of 587 men and 460 women participants have died since the study began, with the men having the higher mortality rate of 24.8 per 1,000 person years, compared to only 16.5 per 1,000 person years for the women. For then men having severe sleep-disordered breathing, the risk of death was doubled that of people with no sleep-disordered breathing (32.2 per 1,000 person–years versus16.8 per 1,000 person-years). Too few deaths occurred among the women who had severe sleep apnea for the researchers to draw conclusions at this point, however researchers believe that further research will reveal similar results. People having milder sleep-breathing disorders were not found to be more likely to die early.

According to Dr. David Rapoport of New York University, who worked on the study, “The best treatment for sleep apnea is weight loss. However, the most successful treatment can be a nasal CPAP (continuous positive airway pressure) mask that applies pressure to help keep the airways of a patient open while they sleep, allowing normal breathing.” Rapoport also added, “Another possible helpful treatment is surgery. That may include tonsil removal.” He further noted, “A mouth guard that pulls a patient's mouth forward is another option.”

The researchers hope to conduct clinical trials in the future to determine whether or not treatment of the condition can play a role in reducing premature deaths.