New results from a nationwide study on factors that affect asthma in inner-city children show that cockroach allergen appears to worsen asthma symptoms more than either dust mite or pet allergens.
This research, funded by the National Institute of Environmental Health Sciences (NIEHS) and the National Institute of Allergy and Infectious Diseases (NIAID), is the first large-scale study to show marked geographic differences in allergen exposure and sensitivity in inner-city children. Most homes in northeastern cities had high levels of cockroach allergens, while those in the south and northwest had dust mite allergen levels in ranges known to exacerbate asthma symptoms.
The study results are published in the March issue of the Journal of Allergy and Clinical Immunology.
"These data confirm that cockroach allergen is the primary contributor to childhood asthma in inner-city home environments," said NIEHS Director Kenneth Olden, Ph.D. "However, general cleaning practices, proven extermination techniques and consistent maintenance methods can bring these allergen levels under control."
Cockroach allergens come from several sources such as saliva, fecal material, secretions, cast skins, and dead bodies. People can reduce their exposure to cockroach allergen by eating only in the kitchen and dining room, putting non-refrigerated items in plastic containers or sealable bags, and taking out the garbage on a daily basis. Other measures include repairing leaky faucets, frequent vacuuming of carpeted areas and damp-mopping of hard floors, and regular cleaning of counter tops and other surfaces.
NIH provided $7.5 million to researchers at the University of Texas Southwestern Medical Center at Dallas and seven other research institutions, including the Data Coordinating Center at Rho, Inc., for the three-year study.
"We found that a majority of homes in Chicago, New York City and the Bronx had cockroach allergen levels high enough to trigger asthma symptoms, while a majority of homes in Dallas and Seattle had dust mite allergen levels above the asthma symptom threshold," said Dr. Rebecca Gruchalla, associate professor of internal medicine and pediatrics at the University of Texas Southwestern Medical Center and lead author of the study.
"We also discovered that the levels of both of these allergens were influenced by housing type," noted Gruchalla. "Cockroach allergen levels were highest in high-rise apartments, while dust mite concentrations were greatest in detached homes."