Asthma diagnosis and treatment
Inner City Asthma Study: Relationships among sensitivity, allergen exposure, and asthma morbidity

https://doi.org/10.1016/j.jaci.2004.12.006Get rights and content

Background

Asthma-associated morbidity is rising, especially in inner city children.

Objective

We evaluated the allergen sensitivities, allergen exposures, and associated morbidity for participants in the Inner City Asthma Study. We also determined geographic variations of indoor allergen levels.

Methods

Nine hundred thirty-seven inner city children 5 to 11 years old with moderate to severe asthma underwent allergen skin testing. Bedroom dust samples were evaluated for Der p 1, Der f 1, Bla g 1, Fel d 1, and Can f 1.

Results

Skin test sensitivities to cockroach (69%), dust mites (62%), and molds (50%) predominated, with marked study site–specific differences. Cockroach sensitivity was highest in the Bronx, New York, and Dallas (81.2%, 78.7%, and 78.5%, respectively), and dust mite sensitivity was highest in Dallas and Seattle (83.7% and 78.0%, respectively). A majority of homes in Chicago, New York, and the Bronx had cockroach allergen levels greater than 2 U/g, and a majority of those in Dallas and Seattle had dust mite allergen levels greater than 2 μg/g. Levels of both of these allergens were influenced by housing type. Cockroach allergen levels were highest in high-rise apartments, whereas dust mite allergen levels were highest in detached homes. Children who were both sensitive and exposed to cockroach allergen had significantly more asthma symptom days, more caretaker interrupted sleep, and more school days missed than children who were not sensitive or exposed.

Conclusion

Geographic differences in allergen exposure and sensitivity exist among inner city children. Cockroach exposure and sensitivity predominate in the Northeast, whereas dust mite exposure and sensitivity are highest in the South and Northwest. Cockroach allergen appears to have a greater effect on asthma morbidity than dust mite or pet allergen in these children.

Section snippets

Methods

The ICAS enrolled 937 children (of 1059 children screened) age 5 to 11 years and their caretakers from 7 metropolitan inner city areas in the United States. In a fully crossed factorial design, study participants were randomized to receive an environmental allergen reduction intervention, an intervention providing bimonthly feedback regarding the child's clinical status to the children's primary care physician, both interventions, or neither intervention. The sample size was chosen on the basis

Results

Of 1059 children skin tested, 994 (93.9%) had a positive skin test result to 1 or more of the allergens used in the testing. Of these 994 children, 937 (94.3%) successfully completed the baseline home evaluation and were enrolled. Table I describes the characteristics of all of the participants and their homes. As shown, the children in the control group, the only group examined in the morbidity analysis, had characteristics that were not appreciably different from the entire population

Discussion

Results from the ICAS demonstrate that skin test reactivity and allergen levels vary widely depending on location in the country. The majority of enrolled children were allergic to dust mite and/or cockroach allergens, and positive skin test responses were related to the levels of these allergens in the child's bedroom. In addition, we found that children who were allergic to cockroach and exposed to cockroach allergen had more asthma symptoms, more school days missed because of asthma, and

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    Supported by grants AI-39769, AI-39900, AI-39902, AI-39789, AI-39901, AI-39761, AI-39785, and AI-39776 from the National Institute of Allergy and Infectious Diseases, National Institutes of Health, Department of Health and Human Services, and the National Institute of Environmental Health Sciences, National Institutes of Health, Department of Health and Human Services, and by grant M01 RR00533 from the National Center for Research Resources.

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