PHILADELPHIA — Sleep apnea, a disorder that causes sleepers to stop breathing many times each night, tends to be more severe in men under 45 than in elderly sufferers, according to a new study.
The study challenged a long-held belief that sleep apnea is more serious in older people.
The finding came after five years of research at Penn State's College of Medicine in Hershey sponsored by the National Institutes of Health. The researchers interviewed 4,364 men by phone and later examined 741 who reported such apnea symptoms as snoring and daytime sleepiness.
They found that, among patients suffering from apnea, younger men had the lowest levels of saturated oxygen, meaning that they weren't getting enough oxygen while sleeping. Over time, the low levels of saturated oxygen can lead to high blood pressure and severe strain on the heart.
"It's very important to diagnose earlier and treat early," said professor Edward Bixler, author of the study, which appears in January's issue of the American Journal of Respiratory and Critical Care Medicine. It is considered the largest study of sleep apnea in men, he said.
"Even mild cases of sleep apnea need to be treated more aggressively in the young," he said. Physicians need to be more vigilant about asking younger men whether they snore at night, feel drowsy during the day, or have high blood pressure.
The most common treatment is called continuous positive air pressure. A sleeper wears a mask all night, hooked up to an air compressor, to ensure proper breathing. Many users, however, find it difficult to wear the mask on a regular basis.
About 7 million to 18 million Americans suffer from sleep apnea, which occurs when a person stops breathing for at least 10 seconds, 10 or more times for each hour of sleep. Often it happens when a person's soft palate obstructs the airway.
About 38,000 people die every year from heart complications of apnea, according to a 1994 report to Congress by the National Commission on Sleep Disorders Research. Older and obese people are especially at risk.
The Penn State study found that sleep apnea is more prevalent in older men but less likely in men older than 55.
Its prevalence increased from 0.4% in 20- to 29-year-old men to 1.5% in 30- to 39-year-old men to 2.8% in 40- to 49-year-old men to 5.4% in 50- to 59-year-olds. The likelihood declined to 4.2% among 60- to 69-year-old men and 2.5% in men older than 70.
"It probably follows the fairly typical pattern seen in other diseases," said Michelle Merker, assistant director of the Sleep Disorder Center at the Research Medical Center in Kansas City. Patients with severe apnea might die of stroke or cardiovascular disease in their 60s, reducing the number of elderly sufferers.
"Why you don't see more elderly who are very severely afflicted . . . is that you're dealing with a 'survivor' population," Bixler said.
He said the findings also support the belief that apnea in younger men is probably genetic, while older men have developed the ailment because of the aging process.
Apnea is more common in men than in women, but Bixler said he has begun a study on female sufferers.