And now a new study finds that blacks are more prone to this potentially dangerous condition than whites. They're also less likely to seek treatment for the disorder.
Almost 80 percent of blacks have common signs of obstructive sleep apnea, while only 55 percent of whites do, according to a study presented at the American Academy of Otolaryngology Head and Neck Surgery annual meeting, which began Sunday in Los Angeles.
"Here you have a population that's at far greater risk to have the problem, and that's more likely to be adversely affects by sequelae of the disease, like hypertension and obesity," said Dr. Michael Friedman, chairman of head and neck surgery at Rush-Presbyterian-St. Luke's Medical Center in Chicago. On top of that, "they're less likely to get the treatment they need," he said.
Friedman said that it's important to identify sleep apnea early on, because there are more treatment options available at that stage.
Obstructive sleep apnea, or OSA, affects as many as 12 million Americans, according to the American Sleep Apnea Association. The most common symptom is loud snoring. Sometimes, the muscles in the back of the throat relax so deeply, that the airway is cut off, and breathing can stop for as long as 10 seconds. This lack of air and oxygen can startle sleepers awake, though they may not realize it.
"Most people are oblivious," said Friedman. "They are completely unaware of the problem, or they're in denial that they snore."
But, he said, sleep apnea can be serious if left untreated. Some problems associated with sleep apnea include daytime sleepiness, an inability to pay attention or focus, morning headaches and weight gain, according to the National Library of Medicine. Sleep apnea has also been linked to obesity, hypertension and heart disease, Friedman said.
To obtain a random sample from the general population, Friedman and his colleagues set up a sleep apnea screening booth at a large Chicago health fair attended by more than 80,000 people.
A total of 523 participants were interviewed, including 287 blacks (55 percent) and 236 whites (45 percent). The average age of the study participants was 44. Blacks included in the study tended to have a higher body mass index (BMI) compared to the whites: 32 versus 28 (for reference, statistical overweight begins with a BMI of 25, obesity at 30).
The researchers looked for signs of obstructive sleep apnea, such as tongue position and tonsil and neck size. By combining these signs, and assigning them a numeric value, the researchers were able to assess the risks for sleep apnea.
The resulting OSA score was higher for blacks vs. whites, at 7 vs. 5.9, respectively. Blacks were also more likely to report daytime sleepiness, a major symptom of sleep apnea.
The researchers don't know for sure why blacks might be at higher risk for sleep apnea than whites, but Friedman said the study found that blacks had a higher average BMI, larger tonsil size and larger neck size -- all of which are risk factors for sleep apnea.
In addition to the physical findings, the researchers also questioned the attitudes of study participants' spouses when it came to their partner's snoring.
Only 18 percent of blacks said they had ever left the bedroom due to spousal snoring, while 30 percent of white spouses said they had done so. When asked if snoring was "normal," 32 percent of blacks said it was compared to just 19 percent of whites.
"Obviously, there is less of a sensation that [sleep apnea] needs to be addressed or treated" among blacks, said Friedman.
"One of the main reasons people come in for treatment is because of the snoring, and their partner complaining about the snoring," noted Dr. Kelvin Lee, director of the division of general otolaryngology and sleep surgery at the New York University Medical Center.
"From this study, it appears that in the black community there isn't a perception of snoring being a problem. That's a big opportunity for outreach and education," he said.
Lee said his only real issue with this study was that people were diagnosed with sleep apnea using the OSA score, rather than traditionally recognized sleep studies.
Another study presented at the meeting found that in young, healthy U.S. Air Force personnel, mild sleep apnea doesn't appear to affect aerobic fitness. However, those with moderate to severe obstructive sleep apnea were less aerobically fit than their counterparts who didn't have sleep apnea.
Both Friedman and Lee said it's important for people to realize that sleep apnea can be a serious problem, and the sooner it's treated, the better.
"This is not something where you're going to die tomorrow, but it puts such a strain on the system, it can give you high blood pressure and heart trouble because your body has to compensate. It's dangerous to have sleep apnea long-term. You're probably more likely to die earlier if you don't treat it," said Lee.
Friedman said that, along with getting a sleep study to diagnose sleep apnea, it's a good idea to also see an otolaryngologist for a full range of treatment options.
More information
The American Sleep Apnea Association offers more information on sleep apnea.
Why are some people drawn to risky behaviors while others remain more cautious? New research with mice suggests a single gene may be key.
Scientists at the Fred Hutchinson Cancer Research Center in Seattle found that a neurodevelopmental gene called neuroD2 is related to the development of the amygdala, the brain's emotional center. They also found that this gene directs the formation of both emotional memory and the fear response.
"Most of us are familiar with the fact that we can remember things better if those memories are formed at a time when there is a strong emotional impact -- times when we are frightened, angry or falling in love. That's called emotional-memory formation. The amygdala is the part of the brain that is responsible for formation of emotional memory," research leader Dr. James Olson, associate member of Hutchinson's Clinical Research Division, said in a prepared statement.
His team studied mice with a single copy of neuroD2, and found that these mice had a reduced ability to form emotional memories and conditioned fear, compared to normal mice with two copies of the gene. The researchers also found that mice with a single copy of neuroD2 had fewer nerve cells in the amygdala than normal mice.
The study appears in this week's online issue of the Proceedings of the National Academy of Sciences.
"The contribution we have made is showing that neuroD2 is related to the development of the amygdala. This is the first time that a specific neurodevelopment gene has been related to these emotional activities in the brain," Olson said.
Further research is needed to better understand how this gene may affect human behaviors such as risk-taking and the fear response.
"The question is, are there differences in the neuroD2 gene-coding sequence or differences downstream of the neuroD2 pathway during brain development that could affect either psychiatric or emotional functions in humans? It's a completely unexplored question," Olson said. And he said it's "the immediate next question you would go to if you want to understand how this gene impacts human behavior."
More information
The American Academy of Family Physicians offers advice on emotional health.
