THE ROLE OF COCKROACH ALLERGY AND EXPOSURE TO COCKROACH ALLERGEN IN CAUSING MORBIDITY AMONG INNER-CITY CHILDREN WITH ASTHMA

Background It has been hypothesized that asthma-related health problem s are most severe among children in inner-city areas who are allergic to a specific allergen and also exposed to high levels of that allerge n in bedroom dust. Methods From November 1992 through October 1993, we recruited 476 children with asthma (age, four to nine years) from eig ht inner-city areas in the United States. Immediate hypersensitivity t o cockroach, house-dust-mite, and cat allergens was measured by skin t esting. We then measured major allergens of cockroach (Bla g 1), dust mites (Der p 1 and Der f 1), and cat dander (Fel d 1) in household dus t using monoclonal-antibody-based enzyme-linked immunosorbent assays. High levels of exposure were defined according to proposed thresholds for causing disease. Data on morbidity due to asthma were collected at base line and over a one-year period. Results Of the children, 36.8 p ercent were allergic to cockroach allergen, 34.9 percent to dust-mite allergen, and 22.7 percent to cat allergen. Among the children's bedro oms, 50.2 percent had high levels of cockroach allergen in dust, 9.7 p ercent had high levels of dust-mite allergen, and 12.6 percent had hig h levels of cat allergen. After we adjusted for sex, score on the Chil d Behavior Checklist, and family history of asthma, we found that chil dren who were both allergic to cockroach allergen and exposed to high levels of this allergen had 0.37 hospitalization a year, as compared w ith 0.11 for the other children (P=0.001), and 2.56 unscheduled medica l visits for asthma per year, as compared with 1.43 (P<0.001). They al so had significantly more days of wheezing, missed school days, and ni ghts with lost sleep, and their parents or other care givers were awak ened during the night and changed their daytime plans because of the c hild's asthma significantly more frequently. Similar patterns were not found for the combination of allergy to dust mites or cat dander and high levels of the allergen. Conclusions The combination of cockroach allergy and exposure to high levels of this allergen may help explain the frequency of asthma-related health problems in inner-city children . (C)1997, Massachusetts Medical Society.