Effect of mouse allergen and rodent environmental intervention on asthma in inner-city children

BACKGROUND: Mouse allergens are prevalent in inner-city households, and increasing levels of exposure are associated with sensitization in children with asthma. OBJECTIVES: To examine mouse allergen sensitization and exposure in inner-city children, mouse allergen as an independent risk factor for asthma morbidity, and the efficacy of a rodent environmental intervention. METHODS: We conducted a subanalysis of children with asthma aged 5 to 11 years enrolled in the Inner-City Asthma Study. After randomization, 150 participants received a home rodent-specific environmental intervention. Asthma morbidity measures were obtained bimonthly. Bedroom dust was collected and analyzed for Mus m 1 at baseline and every 6 months for 2 years. RESULTS: Twenty-two percent of children tested positive to mouse. Most bedrooms (80%) had detectable mouse allergen. Sensitization occurred at low levels of exposure. Sensitization and exposure were associated with increased asthma morbidity, including hospitalizations. Mouse allergen levels on the bedroom floor decreased 27.3% (95% confidence interval, -46.1% to -1.9%) in intervention homes. Mouse allergen reduction was associated with less missed school, sleep disruption, and caretaker burden but not symptoms or medical utilization. CONCLUSIONS: Mouse allergen is prevalent in inner-city homes. Sensitization seems to occur at low levels of exposure. Mouse allergen is an independent risk factor for asthma morbidity. The described environmental intervention reduced mouse allergen levels and asthma-related sleep and activity disturbance.