Methods: 350 mouse-sensitized and exposed asthmatic children (5-17y) were enrolled in a clinical trial of integrated pest management + education versus education alone. Symptoms and mouse allergen exposure were assessed every three months. Sensitization was defined as a skin prick test ≥3 mm, mouse allergen reduction as ≥75% decrease in bedroom floor mouse allergen from baseline, and exposure as detected vs. non-detected via previously defined cut-points. Groups were combined for analyses, as they did not differ in exposures or clinical outcomes. Analyses were stratified by allergen sensitized and exposed and interaction terms were created (e.g.: cat sensitized&exposed*≥75% exposure reduction). Regression models included sex, age, race, and type of insurance.
Results: Participants were low-income, urban asthmatic children with persistent asthma (79% African-American, 62% male, 88% Medicaid). The prevalences of sensitization/exposure were: 41% cat, 15% dog, 11% dust mite, 6% rat, 57% any. Participants who were not sensitized/exposed to other indoor allergens had a greater reduction in maximal asthma symptom days in response to mouse allergen reduction than sensitized/exposed participants(OR[95% CI]: 0.69[0.52-0.91 ] vs. 1.32[0.1.06-1.64], pint<0.0001). Similar associations were seen with exercise-associated symptoms(0.56[0.36-0.87] vs. 1.06[0.72-1.54], pint=0.038) and nocturnal symptoms(0.80[0.58-1.11] vs. 1.23[0.91-1.68] pint=0.036).
Conclusions: Mouse-sensitized/exposed asthmatic children who are sensitized/exposed to additional allergens in the home do not appear to experience an improvement in daily symptoms with mouse allergen reduction.