Cockroach allergen exposure and sensitization in suburban middle-class children with asthma

Background: Exposure to cockroach allergen is prevalent in inner-city homes and is associated with an increased risk of cockroach sensitization. Objective: We sought to determine the prevalence of cockroach allergen exposure in suburban middle-class homes and to study its relationship to cockroach sensitization. Methods: Children with asthma, 6 to 17 years of age, were recruited from 3 pediatric practices located in counties surrounding Baltimore city and from 1 practice located within Baltimore city limits. Participants underwent skin prick testing and completed baseline questionnaires. In addition, their homes were inspected, and settled dust samples were collected for allergen analysis. Results: Forty-one percent of the total study population (n = 339) had kitchen Bla g 1 levels of greater than 1 U/g. Forty-nine percent were white, 53% had annual incomes of greater than $50,000, and 48% of mothers had college degrees. Seventy-seven percent of the study population resided in a suburban or rural location, and 30% of kitchens in these homes had Bla g 1 levels of greater than 1 U/g. Among the suburban-rural subgroup, 21% were sensitized to cockroach compared with 35% of the city group. In multivariate analysis, exposure to kitchen Bla g 1 levels of greater than 1 U/g was associated with cockroach sensitization for both the total study population (odds ratio, 2.29; 95% CI, 1.28-4.11) and the suburban-rural subgroup (odds ratio, 2.37; 95% CI, 1.23-4.57). Conclusions: Cockroach allergen exposure might be more common in suburban middle-class homes of asthmatic children than previously thought. Moreover, the data suggest that low-level cockroach exposure is a risk factor for cockroach sensitization.