(New York) – Researchers at Mount Sinai School of Medicine have found that taking steps to reduce exposure to allergens and tobacco smoke in the home can significantly reduce asthma symptoms in inner-city children.

Mount Sinai was among seven asthma centers across the country that participated in a study sponsored by the National Institutes of Health whose results appear in the September 9th issue of The New England Journal of Medicine.

The study found that an environmental intervention program that targets allergens and tobacco smoke in the home can produce a reduction in symptoms comparable to that achieved with asthma inhalers. These findings demonstrate that promising results can be achieved by families that incorporate allergen-reduction practices into their everyday lives.

Asthma affects about 20 million Americans, and African-American and Hispanic children who live in inner-city area suffer disproportionately from the disease. Increased asthma symptoms in that population is believed to be related to exposure to high levels of various indoor allergens and tobacco smoke.

"Asthma is the most serious child health problem for our nearby East Harlem neighborhood," noted Meyer Kattan, MD, Professor and Chief of the Division of Pediatric Pulmonology and Critical Care, and principal investigator for the portion of the research conducted at Mount Sinai. "East Harlem has the highest incidence of childhood asthma in the country and asthma hospitalization rates for East Harlem children up to age fourteen are almost three times higher that for Manhattan and New York City."

The study involved more than 900 children ages 5 to 11, most of whom were African American or Hispanic, living in low-income sections of seven major metropolitan areas across the country, including Manhattan. Each was allergic to at least one common indoor environmental allergen, such as cockroach allergen or house dust mite allergen. They were randomly assigned to either an intervention group or a control group.

Based on the child's sensitivity to the selected indoor allergens and evidence of exposures at home to known asthma triggers, investigators designed an individualized environmental intervention, carried out by the child's mother or another caretaker. The intervention focused on educating the family about ways to reduce or eliminate all allergens to which the child was allergic, as well as to reduce exposure to tobacco smoke, and motivating them to pursue these steps. The investigators developed separate interventions tailored to tobacco smoke and to the following allergens--house dust mite, cockroach, pet, rodent and mold.

In addition, families were given specific allergen-reducing measures, such as allergen-impermeable covers for children's bedding and air purifiers with HEPA (high efficiency particulate air) filters, to be placed in key locations within their homes, including the children's bedrooms. Cockroach extermination visits were provided for children who were allergic to cockroach allergens. During the first year of the study, the investigators conducted educational home visits with the families in the intervention group. Throughout the yearlong study and the one-year follow-up, researchers closely monitored all participants' asthma symptoms and home allergen levels.

Children who participated in the intervention had significantly fewer asthma symptoms compared with those in the control group: an average of 21 fewer days of symptoms in the first year and an average of 16 fewer days during the second, or follow-up, year. In addition, the benefits of the intervention occurred rapidly: Investigators noted significant reductions in symptoms just 2 months after the study began.

The levels of cockroach and dust mite allergens in the children's bedrooms in the intervention group were substantially lower than in the control group. Furthermore, the researchers noted a direct correlation between allergen levels and asthma symptoms for the children in the intervention group: The greater the drop in cockroach or house dust mite allergen levels, the greater the reduction in asthma symptoms, suggesting that the allergy-reducing measures made the difference.

Most previous environmental intervention studies focused on controlling a single allergen or tobacco smoke, and met with limited success.

The research was co-funded by the National Institute of Allergy and Infectious Diseases (NIAID) and the National Institute of Environmental Health Sciences (NIEHS), which are part of the National Institutes of Health (NIH), an agency of the U.S. Department of Health and Human Services. The project is part of the Inner City Asthma Study, a cooperative multi-center initiative comprising seven asthma study centers across the country and a statistical center.