Researchers armed with vacuum cleaners collected samples of the dust in American bedding, and though they found no lions, tigers or bears, they found plenty of cause for concern in terms of dust mite and cockroach allergens at levels associated with asthma and allergies.
Called the First National Allergen Survey, the study was led by scientists at the National Institute of Environmental Health Sciences (NIEHS), a part of the National Institutes of Health, and done in collaboration with investigators at the U.S. Department of Housing and Urban Development; Harvard University, and Westat, Inc.
The study was done in light of mounting evidence that exposure to indoor allergens from dust mites and cockroaches is a risk factor for the development of allergic diseases and asthma. Indoor dust from five or six different states in each of 831 homes from 75 different areas across the U.S. was collected, along with demographic and health information of home occupants. The 75 areas were selected as representative of the U.S. with respect to region, ethnicity, socioeconomic status and housing characteristics.
Survey results suggest that over 45% of the U.S. housing stock, of approximately 44 million homes have bedding with dust mite allergen concentrations that exceed 2 micrograms per gram of dust, a level that has been associated with the development of allergies. Of these, over 23% of U.S. homes or about 22 million dwellings, are estimated to have bedding with dust mite allergen concentrations that exceed 10 micrograms per gram of dust, a level associated with the trigger of asthma symptoms in asthmatics who are allergic to these allergens.
Further, results indicate that 17% of household occupants reported problems with cockroach infestations in the year preceding the study. Cockroach allergen is estimated present at detectable levels in bedding in over 6% of all U.S. homes, representing almost 6 million households. The number of homes with detectable cockroach allergen is expected to be much higher since the kitchen is typically the most common site of cockroach activity. Data on kitchen levels of cockroach allergen will become available next year.
This study suggests that a large number of U.S. homes contain dust mite allergen levels which pose a significant risk for the development of allergies and asthma, Patrick Volta, Ph.D., of NIEHS, said. There are housekeeping practices as well as allergen proof bedding covers that can be used to reduce exposures to high levels of allergens. For people who are not allergic to these allergens, steps to reduce exposure may reduce the chance of developing allergies and asthma. For those who are already allergic and/or asthmatic, steps to reduce exposure may decrease the frequency and severity of the symptoms of these diseases.
For more information go to www.niehs.nih.gov
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