Edited by Douglas Harbrecht

INNER-CITY ASTHMA: BLAME IT ON THE ROACHES

One of the many mysteries about asthma is why the breath-constricting disease strikes up to three times as often in inner cities than in the rest of America. Possible explanations have included everything from more exposure to cigarette smoke to higher levels of dust mites. Now comes a new study that finally pins part of the blame on one culprit: cockroaches.

Many cases of asthma are triggered by an allergic response to a specific substance. So in a study reported in the May 8, 1997, issue of the New England Journal of Medicine, a team of scientists led by David Rosenstreich of Albert Einstein College of Medicine examined more than 400 inner-city asthmatic children to see what substances they were allergic to. Then they gathered dust samples from the children's homes to identify out what chemicals were common.

The results were striking: More than one-third of the children were allergic to a substance produced by cockroaches, nearly twice as many as were allergic to cats. What's more, the dust in more than half the homes was laden with cockroach allergen, compared to only 12% filled with cat allergen. The scientists suggest that exposure to high levels of the cockroach substance makes children hypersensitive to the chemical. Then, when the children keep breathing it in, they suffer allergic reactions -- and asthma.

By John Carey in Washington