RALEIGH, N.C. (AP) â€” Droppings left on pillows and bedding by dust mites and cockroaches may be triggering more asthma and allergy attacks than previously realized.
Researchers at the National Institute of Environmental Health Sciences in North Carolina's Research Triangle Park surveyed a sample of homes around the country and vacuumed dust from their beds.
They found that certain proteins from dust mites â€” microscopic arachnids that thrive in humid places and feed on human skin flakes â€” are present in large enough quantities to cause allergies in more than 45 percent of U.S. households.
In an estimated 23 percent of American homes, the level of dust mite allergens is high enough to trigger asthma attacks, the researchers said. That number, which represents about 22 million homes, shocked environmental health researchers.
Dr. Darryl Zeldin, head of clinical studies at NIEHS, said he had thought the number would be closer to 10 percent.
``Twenty-three percent. Nobody would have guessed that,'' Zeldin said. ``Our beds are teeming with dust mite allergens.''
The allergenic droppings of cockroaches were detected in 6 percent of bedding.
Dust allergies can cause congestion, headaches and sore throats, and asthma has left an estimated 17 million Americans wheezing.
The researchers' findings, to be presented Wednesday to the American Lung Association/American Thoracic Society conference in Toronto, were part of the First National Allergen Survey, a three-year, government-funded $1 million effort based on a sample of 831 homes across the nation.
From July 1998 to December 1999, technicians went to each home with a hand-held vacuum cleaner equipped with a special dust-collecting filter. They vacuumed the main sleeping pillow and all layers of bedding, down to the top surface of the mattress, said Patrick Vojta, an NIEHS clinical studies coordinator.
On the Net:
National Institute of Environmental Health Sciences: http://www.niehs.nih.gov