Cockroaches Tied to Asthma in Inner Cities
Cockroach allergies may be the most important cause of asthma in America’s inner cities, where rates of the breathing disorder have been skyrocketing, a major new study has found.
Moreover, allergies to the creeping pest provoke an unusually severe form of asthma that is probably the source of the disproportionately high incidence of asthma-related illnesses and hospitalizations in urban neighborhoods, the study said.
In the report, from a $17-million, eight-city study of asthma, researchers found that more than one-third of asthmatic children were allergic to cockroaches and half had high levels of cockroach droppings and debris in their bedrooms, where the youths spent most of their time, whether awake or asleep.
Those children who had the double whammy of being allergic to cockroaches and exposed to their leavings were three times as likely to be hospitalized for asthma and twice as likely to require unscheduled medical services, the team reports today in the New England Journal of Medicine. The allergic group also had significantly more days of wheezing, more missed school days and more nights with lost sleep.
“Prior to this study, we suspected that cockroaches played a role†in inner-city asthma, said Dr. Floyd Malveaux of the Howard University College of Medicine in Washington. “This is the first time that a cause-and-effect relationship [between cockroaches and asthma] has been demonstrated.â€
The results suggest that eradicating cockroaches in the inner cities “should be an important component of plans for the management of asthma,†said Dr. David L. Rosenstreich of the Albert Einstein College of Medicine, the study’s head.
Asthma affects 15 million Americans, causing 500,000 hospitalizations and 5,000 deaths each year. The number of asthma cases has more than doubled since 1980, according to the U.S. Centers for Disease Control and Prevention--a phenomenon that has been occurring around the world as well.
Rates are highest in the inner city, especially among African Americans and children, and researchers have been mystified about the reason. Suggested causes have included the improved construction and insulation of housing, which traps allergens inside; the sharply increased amount of time children spend inside, watching television and playing video games; and children’s failure to get adequate exercise.
But those changes in lifestyle alone were not enough to trigger the increases in asthma, and researchers suspected that something within the household environment must be provoking the inflammation of the airways that characterizes asthma. Previous studies have shown that dust mite allergens and animal dander can provoke asthma and play a major role in asthma in some locations. But those factors, other studies have suggested, do not seem to be that important in the inner cities.
To look for answers, the National Institute of Allergy and Infectious Diseases launched a major study in which researchers enrolled 1,528 children from the Bronx and East Harlem in New York, St. Louis, Washington, Detroit, Baltimore, Chicago and Cleveland. They administered allergy tests, vacuumed up dust throughout their dwellings, and analyzed its contents and monitored the children’s medical profiles.
Today’s study reported on the first 476 children, ages 4 to 8, enrolled in the study. Nearly 37% of them were allergic to cockroach allergens, primarily proteins found in saliva and droppings, 34.9% were allergic to dust mite allergens and 22.7% to cat allergens.
But while more than half had high levels of cockroach allergens in their bedrooms, only 9.7% had high levels of dust mite allergens and 12.6% had high levels of cat allergens. And those children who were allergic to cockroaches and had high levels of allergen in their bedrooms were the sickest.
The study demonstrates “a clear, causal relationship between cockroach allergy, high levels of exposure to cockroaches and asthma severity,†said Dr. Daniel Rotrosen of the national allergy institute.
“I don’t think people appreciated the significant role that cockroach allergens would be playing in asthma,†said Nancy Sander, the president of the Allergy and Asthma Network/Mothers of Asthmatics.
Rosenstreich estimates that cockroach allergies account for about a quarter of asthma cases in the inner city.
The study now will focus on eradicating cockroaches from the apartments and monitoring the children’s health to see if it improves. Other studies have shown that such apartments often contain as many as 10,000 roaches.
