Sleep Apnea May Boost Risk of Sudden Cardiac Death

Study findings bolster suspected link between sleep disorder and heart-related death

By Kathleen Doheny

HealthDay Reporter

TUESDAY, June 11 (HealthDay News) -- Sleep apnea raises the risk of sudden cardiac death, according to a long-term study that strengthens a link doctors have suspected.

"The presence and severity of sleep apnea are associated with a significantly increased risk of sudden cardiac death," said study leader Dr. Apoor Gami, a cardiac electrophysiologist at Midwest Heart Specialists-Advocate Medical Group in Elmhurst, Ill.

The new research is published online June 11 in the Journal of the American College of Cardiology.

Sleep apnea -- in which a person stops breathing frequently during sleep -- affects about 12 million American adults, although many are not diagnosed. The diagnosis is made after sleep tests determine that a person stops breathing for 10 seconds or more at least five times hourly while sleeping.

Some research suggests that sleep apnea is on the rise, in part because of the current obesity epidemic.

Sudden cardiac death kills 450,000 people a year in the United States, according to study background information. It occurs when the heart unexpectedly and suddenly stops beating due to problems with the heart's electrical system. Those problems cause irregular heartbeats. The condition must be treated within minutes if the person is to survive.

Electrophysiologists are cardiologists who treat these heart rhythm problems.

In earlier research, Gami and his team had found that patients with sleep apnea who suffered sudden cardiac death often did so at night, a completely opposite pattern than found in others without sleep apnea who had sudden cardiac death.

"That was the first direct link [found] between sudden cardiac death and sleep apnea," Gami said.

In the new study, the researchers tracked more than 10,000 men and women, average age 53, who were referred for sleep studies at the Mayo Clinic Sleep Disorders Center, mostly due to suspected sleep apnea, from 1987 through 2003. After sleep tests, 78 percent were found to have sleep apnea.

During the follow-up of up to 15 years, they found that 142 had sudden cardiac arrest, either fatal or resuscitated.

Three measures strongly predicted the risk of sudden cardiac death, Gami said. These include being 60 or older, having 20 apnea episodes an hour or having low blood levels of oxygen.

This "oxygen saturation" drops when air doesn't flow into the lungs. "If the lowest oxygen saturation was 78 percent, or less, their risk of [sudden cardiac death] increased by 80 percent," Gami said. In a healthy person, 95 percent to 100 percent is normal.

Having 20 events an hour would be termed moderate sleep apnea, Gami said.

Gami found a link, not a cause-and-effect relationship, between sleep apnea and sudden cardiac death. He can't explain the connection with certainty, but said there are several possible explanations. For example, sleep apnea is related to the type of heart rhythm problem that causes sudden cardiac death, he said.

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Treating Sleep Apnea Pays Off at Work, Study Finds

THURSDAY, April 11 (HealthDay News) -- Treating sleep apnea, a common sleep disorder, boosts people's productivity at work, according to a new study.

Sleep apnea interrupts breathing during sleep, causing people with the condition to wake up throughout the night. Previous research has shown that people with sleep apnea are less productive at work, usually because of excessive daytime sleepiness.

The new study looked at whether using continuous positive airway pressure (CPAP) during sleep improved the participants' productivity. With CPAP, a patient wears a mask connected to a machine that sends pressurized air into the throat to keep the airway open throughout the night.

The study included 45 people, aged 40 to 56, with sleep apnea who completed questionnaires before and after three months of CPAP treatment.

The 35 patients who closely followed the treatment program had significant improvements in their daytime sleepiness levels and in their work productivity, but this was not the case for the 10 patients who did not follow the treatment program, the investigators found.

The study was scheduled for presentation Thursday at a meeting of the European Respiratory Society and the European Sleep Research Society in Berlin, Germany.

"Continuous positive airway pressure is the gold standard treatment for moderate-to-severe obstructive sleep apnea," study lead author Dr. Evangelia Nena said in a European Lung Foundation news release. "Previous research has shown the potential benefits of CPAP to patients' health and quality of life, and our findings add to this body of evidence, demonstrating the advantages the treatment can have on productivity at work."

Data and conclusions of research presented at meetings typically are considered preliminary until published in a peer-reviewed medical journal.

-- Robert Preidt
Copyright © 2013 HealthDay. All rights reserved. SOURCE: European Lung Foundation, news release, April 10, 2013

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Obesity Crisis May Be Fueling Big Jump in Sleep Apnea Cases

Researcher calls troubled sleep an 'uncalculated cost' of America's weight epidemic

By Randy Dotinga

HealthDay Reporter

FRIDAY, May 10 (HealthDay News) -- The widening American waistline may be feeding an epidemic of sleep apnea, potentially robbing millions of people of a good night's rest, a new study suggests.

The research didn't definitively link the rise in obesity to sleep apnea, and it only looked at 1,520 people, almost all white, in Wisconsin. But study author Paul Peppard believes the findings show a big spike in sleep apnea cases over the past two decades -- as much as 55 percent -- and may translate to the entire United States.

"There are probably 4 million to 5 million people who are more likely to have sleep apnea due to the obesity epidemic," estimated Peppard, an assistant professor of population health sciences at the University of Wisconsin-Madison. "It's certainly an uncalculated cost of the obesity epidemic, an epidemic of its own."

The researchers looked at adults aged 30 to 70 who were monitored as they slept. About 600 to 700 underwent sleep tests between 1988 and 1994, with some continuing to take part along with hundreds of new participants from 2007 to 2010.

The study considered the participants to have moderate-to-severe breathing problems if they had trouble breathing 15 or more times an hour while sleeping.

Sleep apnea is the main cause of breathing problems during sleep. People with the condition often have trouble staying in deep sleep because their throats close, blocking their airways and requiring them to partially awaken to start breathing properly. They don't realize they're waking up and may become very sleepy during the day.

Besides sleepiness, sleep apnea can contribute to heart and other health problems if untreated and increase the risk of work- and driving-related accidents, according to the U.S. National Heart, Lung, and Blood Institute.

The researchers extrapolated their findings to the entire United States and estimated that 10 percent of men aged 30 to 49 currently have symptoms of sleep apnea. The study estimates the number is 17 percent of men aged 50 to 70. For women, the estimate is 3 percent among those aged 30 to 49 and 9 percent among women aged 50 to 70.

Among all groups, heavier people were much more likely than thinner people to suffer from the symptoms.

The study estimates that these numbers have gone up by 14 percent to 55 percent from 1988-1994 to 2007-2010. Peppard estimated that 80 percent to 90 percent of the increase in symptoms is due to the growth in obesity.

But it's hard to know for sure how much of a role that obesity plays in causing more symptoms. While obesity is "almost certainly the biggest factor" in causing sleep apnea, Peppard said, "there's long list of things that cause sleep apnea or are related to sleep apnea, like being older, being male, having a narrower upper airway, having a genetic predisposition to it..."

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