Cockroaches appear to be a significant contributor to asthma attacks among inner-city children in the United States. A study of asthma patients in seven U.S. cities, reported in tomorrow's issue of The New England Journal of Medicine, found that a combination of allergy to cockroaches and exposure to the insects made some children much more likely to suffer from severe asthma. The finding suggests that ridding households of the pests may be a cheap and effective way to reduce serious asthma among disadvantaged children.
Asthma-related deaths have more than doubled since 1980, and poor children in urban areas have been particularly hard hit. As part of the National Cooperative Inner-City Asthma Study, allergist David Rosenstreich of the Albert Einstein College of Medicine in New York City and a team of colleagues examined the effects of three common allergens associated with asthma: the feces of house dust mites, cockroaches, and the feline equivalent of dandruff. The researchers studied 476 asthma patients between the ages of 4 and 9 living in poor neighborhoods. They tested the children for allergies, collected dust samples from the children's homes to measure allergen levels, and interviewed each family about the child's asthma symptoms every 3 months for a year.
The researchers found that children who were both allergic to cockroaches and had high levels of cockroach allergen in their bedrooms were more than three times as likely to be hospitalized for asthma attacks as other children. This high-risk group--some 20% of all the kids--also reported more asthma-related complications, such as missed school or lost sleep. The effect was significant even after accounting for secondhand cigarette smoke, access to health care, and diligence in following prescriptions.
The study confirms many experts' suspicions. "In the North American inner city, cockroach is dominant," says Thomas Platts-Mills, an asthma and allergy specialist at the University of Virginia. But it was a surprise, he says, that cats and dust mites, which had been implicated in other areas, did not appear significant. He also points out that the team could not easily test for other major allergens, including rat and mouse urine and mold.