National prevalence and exposure risk for cockroach allergen in U.S. households.

We characterized the prevalence of cockroach allergen exposure in a nationally representative sample of U.S. homes and assessed risk factors for elevated concentrations.DesignWe used data from the National Survey of Lead and Allergens in Housing, a population-based cross-sectional survey.ParticipantsParticipants were residents of 831 U.S. homes in the survey.Evaluations/MeasurementsWe analyzed allergen, questionnaire, and observational data of 831 U.S. homes.ResultsCockroach allergen (Bla g 1) concentrations exceed 2.0 U/g, a level associated with allergic sensitization, in 11% of U.S. living room floors and 13% of kitchen floors. Concentrations exceed 8.0 U/g, a level associated with asthma morbidity, in 3% of living room floors and 10% of kitchen floors. Elevated concentrations were observed in high-rise apartments, urban settings, pre-1940 constructions, and households with incomes 8.0 U/g were greatest when roach problems were reported or observed and increas...