Association of pediatric asthma severity with exposure to common household dust allergens

Abstract

Background: Reducing exposure to household dust inhalant allergens has been proposed as one strategy to reduce asthma.

Objective: To examine the dose-response relationships and health impact of five common household dust allergens on disease severity, quantified using both symptom frequency and medication use, in atopic and non-atopic asthmatic children.

Methods: Asthmatic children (N=300) aged 4-12 years were followed for 1 year. Household dust samples from two indoor locations were analyzed for allergens including dust mite (Der p 1, Der f 1), cat (Fel d 1), dog (Can f 1), cockroach (Bla g 1). Daily symptoms and medication use were collected in monthly telephone interviews. Annual disease severity was examined in models including allergens, specific IgE sensitivity and adjusted for age, gender, atopy, ethnicity, and mother's education.

Results: Der p 1 house dust mite allergen concentration of 2.0 microg/g or more from the main room and the child's bed was related to increased asthma severity independent of allergic status (respectively, OR 2.93, 95% CI 1.37, 6.30 for 2.0-10.0 microg/g and OR 2.55 95% CI 1.13, 5.73 for 10.0 microg/g). Higher pet allergen levels were associated with greater asthma severity, but only for those sensitized (cat OR 2.41 95% CI 1.19, 4.89; dog OR 2.06 95% CI 1.01, 4.22).

Conclusion: Higher levels of Der p 1 and pet allergens were associated with asthma severity, but Der p 1 remained an independent risk factor after accounting for pet allergens and regardless of Der p 1 specific IgE status.

Figure 1

Der p 1 (A), Der f 1 (B), Fel d 1 (C) and Can f 1 (D) allergen levels measured in the main living area in homes of children sensitized (specific IgE ≥ .35 kU/L, solid white squares) and non-sensitized (specific IgE ≥ .35 kU/L, striped squares) and their association with moderate to severe GINA asthma severity scores (United States Department of Health and Human Services February 2002). The increase in percentage of children with severe asthma with increases in allergen level was significant for Der p 1 (A) regardless of sensitization (p < 0.0001, Cochran-Armitage test for linear trend), but was most striking for those non-sensitized (p < 0.0003).