Exposure to cockroach allergen in the home is associated with incident doctor-diagnosed asthma and recurrent wheezing

Background: Indoor inhaled allergens have been repeatedly demonstrated to w orsen asthma In sensitized individual, but their role in incident asthma is more controversial, Objective: We investigated the relationship between exposure to allergens ( dust mite, cat, and cockroach) measured in the home and incident doctor-dia gnosed asthma and recurrent wheezing in children born to parents with asthm a, allergies, or both. Methods: From an ongoing longitudinal family and birth cohort study, rye id entified 222 siblings (median age, 2.87 years) of the index children. Aller gen levels in the home were measured from dust samples obtained at the begi nning of the study. Incident doctor-diagnosed asthma and recurrent wheezing were determined from questionnaires administered at 14 months and 22 month s after the initial questionnaire, Results: Thirteen (5.9%) children were reported to have Incident asthma, tw enty (9.0%) children had recurrent asthmatic wheezing, and 18 (8.1%) had re current wheezing without asthma, Compared with children living in homes wit h Bla g 1 or 2 levels of less than 0.05 U/g, children exposed to Bra g 1 or 2 levels of 0.05 to less than 2 U/g had a relative risk for incident asthm a of 8.27 (95% confidence interval, 1.04-66.04), whereas children exposed t o Bla g 1 or 2 levels of 2 U/g or greater bad a relative risk for incident asthma of 35.87 (95% confidence Interval, 4.49-286.62). Cockroach allergen exposure was likewise a significant predictor for recurrent asthmatic wheez ing. Neither dust mite nor cat allergen levels were significantly associate d with either outcome. These findings remained after control for several co variates, Conclusion: Exposure to cockroach allergen early in life may contribute to the development of asthma in susceptible children.