Arbes SJ Jr, Cohn RD, Yin M, Muilenberg ML, Friedman W, Zeldin DC. J Allergy Clin Immunol. 2004;114:111–117
Purpose of the Study.
To estimate the levels of dog and cat allergens in US homes and provide the characteristics of households associated with these allergens.
A total of 2456 individuals from 831 permanently occupied, noninstitutional housing units in 75 US locations that permit resident children.
Data for this study were obtained from the National Survey of Lead and Allergens in Housing conducted by the National Institute of Environmental Health Sciences and the US Department of Housing and Urban Development from 1998 to 1999. Vacuum-collected dust samples from a bedroom floor, bed, living room floor, living room sofa, or equivalent piece of upholstered living room furniture were analyzed for concentrations of primary dog allergen (Can f1) and primary cat allergen (Fel d1) in micrograms of allergen per gram of dust by using monoclonal antibody enzyme-linked immunosorbent assays. Housing and household characteristics were determined by questionnaire or observation. Bivariate associations between housing characteristics and the presence of an indoor dog and cat were examined.
At the time of the survey, 55% had no cat or dog in the home for the past 6 months, 10% had both a cat and a dog, 21% had at least 1 dog and no cat, and 13% had at least 1 cat and no dog. The percentage of homes with an indoor dog was higher if they were outside of the Northeast US, were a single family, owned versus rented, had >1 occupant, had an income greater than $20 000.00 per year, and were white. The percentage of homes with an indoor cat was higher if they were in the Northeast or West or were white. A greater concentration of Can f1 was associated with single-family homes with >1 occupant, higher income levels, white race, and forced-air heating and air conditioning and presence of an indoor cat or dog. For Fel d1, a higher geometric mean concentration was associated with living in the West, being white, having an education above the high school level, and presence of an indoor dog or cat. The presence or absence of a cat had the greatest influence. Respectively, Can f1 and Fel d1 were detectable in 93.8% and 96.6% of beds, 95.6% and 96.9% of bedroom floors, 94.9% and 96.1% of living room floors, and 98% and 97.9% of sofas. Of the 97.7% of homes with detectable antigen, 99.9% had detectable Can f1 in at least 1 sample location. Of the 99% of homes with detectable antigen, 100% had detectable Fel d1 in at least 1 sample location. For Can f1 and Fel d1, 55.7% and 66% of US homes exceeded previously published sensitization threshold levels of >2 and >1 μg/g, respectively. Additionally, 34.9% and 34.7% of US homes exceeded the asthma-symptoms threshold for Can f1 and Fel d1.
Can f1 and Fel d1 are ubiquitous allergens in US homes. Levels associated with both sensitization and exacerbation of asthma are found even in homes without cats or dogs. Demographic groups associated with greater likelihood of pet ownership implicate the role of the community as a source of the allergens.
This study demonstrates the need for greater consideration of the role of dog and cat allergens in both the sensitization and symptom exacerbation of allergic diseases in all patients. More importantly, it presents a challenge to identify unique interventions when the source may be outside of the patient’s home.