PURPOSE OF THE STUDY.
To examine the relationship between house dust mite, cockroach exposures and sensitization, and asthma morbidity in children in an inner-city environment.
The subjects were patients from an allergy clinic (n = 86, mostly black, aged 4–17 years) with physician-diagnosed asthma and positive skin-test results to an indoor allergen and living in urban New Orleans, Louisiana. Most of the children were taking daily asthma medications, more than half had had an emergency department visit, almost 75% had had an urgent physician visit, and nearly 25% had had a hospitalization in the previous 4 months.
This was a cross-sectional study. Sociodemographic factors and home characteristics were queried by using a structured questionnaire and by visual observation of the home at study entry. A revised Childhood Respiratory Health Questionnaire was used to measure frequency of health care utilization, asthma symptoms, activity limitation, and medication use during the previous 4 months. Indoor dust samples were collected and analyzed for the presence of dust mite and cockroach content. In vitro–specific immunoglobulin E to dust mites, cat, dog, and cockroach was measured.
Both dust mite and cockroach exposure were associated with sensitivity, but only cockroach showed a strong linear relationship between degree of exposure and sensitization (even low levels of exposure to dust mite were associated with sensitization). Multivariable regression analyses controlling for exposure, sensitization, oral steroid use, and ICU admission revealed that the only variable associated with multiple exposure variables was hospital admission. The odds of reporting a hospitalization in the previous 4 months, using 2 different statistical models, were 4.2- to 5.4-fold higher for children exposed to >2.0 U/g than for those exposed to <2.0 U/g Blag1. There was no increase in odds for hospitalization related to dust mite exposure.
Exposure to cockroach allergens is strongly associated with hospital admissions for asthmatic children living in the inner city regardless of sensitization.
This study's results reaffirm the association between cockroach exposure and severe asthma morbidity and that this association is, to some degree, independent of sensitivity. The failure to show the same relationship for house dust mite might be a result of sample size and the lack of a relationship between exposure and sensitization in this group. It remains to be shown that remediation efforts directed toward cockroach infestation are helpful in decreasing this morbidity.
- Copyright © 2011 by the American Academy of Pediatrics