Alarmingly, the risk exists whether or not the person feels drowsy, said Terry Young, author of the study and a professor at the university's school of preventive medicine.
Young said previous studies have shown that about 17 million Americans - 4 percent of women and 9 percent of men - have moderate to severe apnea, in which breathing is briefly and repeatedly cut off during sleep, often causing a person to wake up. Habitual snoring can be a symptom of sleep apnea.
However, only 10 percent to 15 percent of those with the disorder have been diagnosed, Young said.
``Sleep apnea causes two insults - one is a decrease in oxygenation and another is sleep fragmentation,'' she said.
``That may impact on attention, vigilance and decision-making.''
Thalidomide seen as
treatment for AIDS
Thalidomide, the sedative banned since the 1960s for causing birth defects, has re-emerged as the only effective treatment for AIDS-related mouth ulcers.
A study found that a month of treatment dramatically relieves this painful condition and clears it up entirely in about half who take it.
The drug has also proved useful against leprosy and may also help control some cancers.
Thalidomide, once sold in 48 countries as a sleeping pill and morning sickness cure, was banned worldwide in 1962 after some 12,000 babies were born with missing or malformed limbs, serious facial deformities and defective organs.
It was never sold in the United States.
Cell phones could disrupt
pacemakers, study says
Digital cellular telephones kept in a pocket can disrupt heart pacemakers, according to new tests of nearly 1,000 people whose hearts are kept beating regularly by the devices.
But when the phones are held over the ear, the ``interference does not pose a health risk,'' say the authors of the study, published in today's New England Journal of Medicine.
The study comes at the same time that the Cellular Telecommunications Industry Association, an industry group, has declared Wireless Safety Week, which runs through May 26.
A team led by Dr. David Hayes of the Mayo Clinic in Rochester, Minnesota, explored the pacemaker interference problem by monitoring the hearts of 980 volunteers as five types of hand-held cellular phones were activated at their ear and at portions of the chest or abdomen where the pacemaker's pulse generator was implanted.
The phones caused detectable interference in 20 percent of the cases and produced symptoms - usually heart palpitations, light-headedness or dizziness - 7 percent of the time.