Morgan WJ, Crain EF, Gruchalla RS, et al. N Engl J Med. 2004;351:1068‐1080
Purpose of the Study.
To determine if environmental modification reduces asthma morbidity in inner-city, atopic children.
Asthmatic children (age range: 5–11 years) from inner cities who were skin-test positive to at least 1 of 11 indoor allergens. To be eligible for the study, the children had to have had 1 hospitalization or 2 unscheduled medical visits for asthma in the previous 6 months.
Nine hundred thirty-seven children with atopic asthma (age range: 5–11 years) in 7 major US cities were enrolled in a randomized, controlled trial of an environmental intervention that lasted 1 year and included education and remediation for exposure to both allergens and environmental tobacco smoke. Home environmental exposures were assessed every 6 months, and asthma-related complications were assessed every 2 months during the intervention and for 1 year after the intervention.
For every 2-week period, the intervention group had fewer days with symptoms than did the control group during both the intervention year (3.39 vs 4.20 days; P < .001) and the year afterward (2.62 vs 3.21 days; P < .001). The intervention group had greater declines in the levels of allergens at home, such as Dermatophagoides farinae (Der f1) allergen in the bed (P < .001) and on the bedroom floor (P = .004), Dermatophagoides pteronyssinus in the bed (P = .007), and cockroach allergen on the bedroom floor (P < .001). Reductions in the levels of cockroach allergen and dust-mite allergen (Der f1) on the bedroom floor were significantly correlated with reduced complications of asthma (P < .001).
Among inner-city children with atopic asthma, an individualized, home-based, comprehensive environmental intervention decreases exposure to indoor allergens including cockroach and dust-mite allergens, resulting in reduced asthma-associated morbidity.
Inner-city children with asthma are exposed to many indoor allergens. Reducing the concentrations of these allergens can be extremely challenging, and there has been limited evidence to prove the efficacy of such measures. This study demonstrates that aggressive environmental modification targeting specific allergens can reduce the asthma-related morbidity in this population. Asthmatic children allergic to cockroach and/or dust mite allergens are most likely to benefit from diligent environmental control.