Purpose of the Study. Indoor allergen exposure in early childhood is a known risk factor for allergic sensitization and the development of asthma. This study specifically seeks to determine the concentration of various indoor allergens in day care centers in a humid environment and compare them with their reported normal household levels.
Study Population. A total of 20 day care centers in Tampa, Florida, were surveyed for mite, cat, and cockroach allergens by collecting 1 dust and 2 air samples (1 during the day and 1 during the night).
Methods. Day care center selection was achieved by asking managers for permission to participate in the study and allow collection of dust and air samples. Questionnaires regarding building age, floor covering, and use of insecticide were obtained. Dust samples were collected from a 1-square meter area for 2 minutes by a 1.7-peak horsepower vacuum cleaner. The filters were subsequently removed and transported to the laboratory in a sterile manner. Dust samples were extracted and specifically analyzed for mite (Der p 1 and Der f 1), cat (Fel d 1), and cockroach (Per a 1) allergens. Airborne mite concentrations were analyzed by radioallergosorbent test inhibition.
Results. Four day care centers were noted to have linoleum floors. The rest of the buildings had wall-to-wall carpeting. Mites were identified in dust samples 15 day care centers with allergen levels >2 μg/g of dust, the suggested threshold level for sensitization to group 1 mite allergens, in 40% of the centers. Cat allergen levels were detected in all centers, but were consistently below the suggested threshold sensitization level of 8 μg of Fel d 1 per gram of dust. Cockroach allergen was also found in all the day care centers in variable quantity. Threshold levels for sensitization to Per a 1 have not been established, but the levels detected were similar to typical levels in homes in Tampa.
Conclusions. Dust mite, cat, and cockroach allergens were present in all day care centers in this humid environment. Mite allergen levels in dust exceeded levels associated with sensitization in 40% of the centers. Levels of cat allergen were noted to be lower than levels in homes with cats and were consistently less than known concentrations for sensitization and symptoms. Cockroach allergen was detected in all day care centers in varying levels, similar to levels in local homes.
Reviewers’ Comments. As the authors note, the prevalence of asthma and sensitization to indoor allergens in children attending day care centers in the United States is unknown. Also unknown is the correlation between indoor air quality and respiratory symptoms in the preschool child. Asthma and allergic disease prevalence in the children attending the day care centers were not reported in this study. Allergen exposure in early childhood is a known risk factor for the development of asthma. And it has been documented that symptoms in children with allergic disease improve after removal from an environment with a large allergen burden. This study furthers our knowledge regarding allergen exposure in day care centers. The relationship between allergen burden and development of allergic disease was not looked at in this study.
- Copyright © 2002 by the American Academy of Pediatrics