National Study Shows Dog and Cat Allergens are Universally Present in United States of America Homes

Scientists at the National Institute of Environmental Health Sciences (NIEHS), one of the National Institutes of Health, and the United States of America Department of Housing and Urban Development have found that detectable levels of dog and cat allergens are universally present in United States of America homes. Although allergen levels were considerably higher in homes with an indoor dog or cat, levels previously associated with an increased risk of allergic sensitization were common even in homes without the pets.

This report by Arbes et al., which will appear in the July 2004 issue of the Journal of Allergy and Clinical Immunology, is one of a series of allergen reports from the National analysis of Lead and Allergens in Housing. In that nationally representative analysis of 831 homes, researchers collected dust samples, asked questions, and examined homes.

Interestingly, the researchers found that dog and cat allergen levels were higher among households belonging to demographic groups in which dog or cat ownership was more prevalent, regardless of whether or not the household had the indoor pet. Because dog and cat allergens can be transported on clothing, the researchers speculated that the community, mainly communities in which dog or cat ownership is high, may be an important source of these pet allergens. For pet-allergic patients in such communities, allergen avoidance may be a difficult challenge.

The analysis was conducted using established sampling techniques to ensure that the survayed homes were representative of United States of America homes. The homes were sampled from seventy-five randomly selected areas (usually counties or groups of counties) across the entire country. The 831 homes included all regions of the country (northeast, southeast, midwest, southwest, northwest), all housing types, and all settings (urban, suburban, rural). For statistics derived from the 831 homes, the contribution from each home was weighted as necessary to ensure that the statistics were representative of the United States of America population. Until now, exposure to these allergens had not previously been studied in residential environments on a national scale.

Some air filters have been shown to help allergies from cats dogs and pollen.