Dust Mites Trump Asthma Prevention Guidelines

WEDNESDAY April 16, 2008 -- Trying to alleviate your asthma by eliminating household dust? Forget about it, a new study suggests.

A comprehensive review of 54 dust-control strategy studies found that none was effective enough in reducing exposure to dust mites that it would improve one's asthma. The methods looked at included using chemicals to kill the little buggers, encasing mattresses and pillows in mite-proof covers, frequently washing linens in hot water or bleach, and even tossing toys, plants and furniture out of a home.

"We can conclude with confidence that there is no need to buy expensive vacuum cleaners or mattress covers or to use chemical methods against house dust mites, because these treatments do not work," study author Peter Gotzsche, director of The Nordic Cochrane Centre in Copenhagen, Denmark, said in a prepared statement.

The review was just published in The Cochrane Library.

Dust mites are microscopic arthropods that carry allergens that irritate bronchial passages and trigger asthma attacks. For years, people have tried to defeat dust mites, but they apparently outnumber and outmaneuver human ingenuity.

"If you are wondering why it is that mattress covers and the other strategies are not effective, the likely answer is that all these treatments do not have a large enough effect on the occurrence of allergens from house dust mites," Gotzsche said. "The level of allergens is so high in most homes that what remains after the treatment is still high enough to cause asthma attacks."

Asthma attacks can be brought on in mite-sensitive people even when allergen levels are very low. For example, while some of the anti-dust methods reviewed cut allergen levels in half, even 90 percent elimination proved inadequate to help many asthma sufferers, Gotzsche said.

The review, Gotzsche said, shows people are being mislead by the 2007 U.S. guidelines from the National Asthma Education and Prevention program. The program recommends actions such as putting mattresses and pillows in dust-proof encasings, and weekly hot water washings of sheets, blankets and stuffed toys.

"Reviews and guidelines should reflect the facts," he said. "It is difficult, perhaps, to realize that we cannot really do anything, but there is no evidence to support these guidelines, and they are misleading. It is about time specialists start becoming honest with patients."

More information

The National Heart, Lung, and Blood Institute has more about the causes of asthma.

Posted: April 2008


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