A study designed to reduce the levels of indoor allergens – conducted in the homes of inner-city children with asthma – resulted in fewer asthma exacerbations and unscheduled visits for asthma during a two-year period, according to a UT Southwestern Medical Center at Dallas researcher who participated in the multicenter study.
The National Institutes of Health study, reported in today's The New England Journal of Medicine, showed that an environmental intervention designed to reduce allergen levels in the home indeed led to a marked reduction of irritants. As a result, children living in these homes had fewer problems with their asthma.
"Indoor allergens play an important role in the asthma severity in these children," said Dr. Rebecca Gruchalla, chief of allergy at UT Southwestern and a study author. "We can't just focus on medications. We must also focus on allergen triggers in the home and work with caretakers to decrease or even eliminate these allergens."
Researchers followed more than 900 children ages 5 to 11 with asthma who live in inner-city areas in New York City, Boston, Chicago, Dallas, Seattle/Tacoma, Wash., and Tucson, Ariz. Research teams went to individual households and initiated measures to decrease levels of dust mite, cockroach, dog, cat, rat, mouse and mold allergens. An additional focus was on tobacco smoke. Caretakers were educated about how to perform the various intervention strategies themselves.
Asthma, a chronic lung disease, affects about 20 million Americans. Inner-city children suffer disproportionately from the disease, primarily because of exposure to high levels of multiple indoor allergens and tobacco smoke.
"These study results are exciting because they show that changes made in the home environment can produce a reduction in symptoms comparable to that achieved with asthma inhalers," said Dr. Kenneth Olden, director of the National Institute of Environmental Health Sciences.
Children who participated in the intervention had 21 fewer days of symptoms than the control group in the first year and an average of 16 fewer days during the second, follow-up year.
"We wanted this to have a long-term impact, not just for the duration of the study," Dr. Gruchalla said. "In many cases, we taught them simple cleaning measures to decrease the roach population – things like not leaving food uncovered and caulking obvious cracks in the wall."
Interventions also included encasing the child's mattress, springs and pillow in allergen-impermeable covers; repairing water leaks; and removing carpet from the bedroom, if possible. Families were also given HEPA (high efficiency particulate air) filters. Cockroach extermination visits were provided in homes where children were sensitive to that allergen. The suggestions were typically well-received, Dr. Gruchalla said.
Study participants had suffered at least one asthma-related hospitalization or two asthma-related unscheduled doctor visits the six months prior to enrollment in the study. They also had a positive allergy skin test to at least one of 11 indoor allergens such as dust mites, molds, cockroaches, pets or rodents.
Researchers performed a baseline clinical evaluation, including questionnaires on asthma symptoms, medication use and the home environment. Later, researchers made a baseline home evaluation by visually inspecting and collecting dust from the child's bedroom. The families were then taught how to reduce allergens in their homes, told why it was necessary and given the needed tools to accomplish the task. Researchers followed up by phone and collected information about the child's asthma every few months during the intervention year and one year after.