Factors related to undiagnosed asthma in urban adolescents: a multilevel approach

We report the results of a school-based asthma case-identification survey to determine the prevalence and predictors of possible undiagnosed asthma in a population of urban adolescents.

During school years 2006-2008, middle school students in Oakland, California, completed a brief survey adapted from the International Study of Asthma and Allergy in Children. Students were classified into one of three categories: no asthma, current asthma, or possible undiagnosed asthma. Students reported demographic information and residential address, which was geocoded and matched tract-level data from the US Census 2000, Oakland land use designations, public and assisted housing locations, and distance from closed-access roadways. Logistic regression was used to examine factors associated with possible undiagnosed asthma.

Of the 4,017 students who completed the survey, 4.8% (95% confidence interval [CI]: 4.1, 5.5) were classified as possible undiagnosed asthma. Female students (odds ratio: 1.53, 95% CI: 1.07, 2.19) and students who resided in an urban residential area (odds ratio: 2.05, 95% CI: 1.05, 4.05) had significantly increased odds of classification as "possible undiagnosed asthma" compared to current asthma. Percentage of noncitizen recent immigrants in a census tract was related to increased odds of possible undiagnosed asthma. Residence in a census tract with older residential units was significantly associated with decreased odds of undiagnosed asthma.

In urban settings, school-based asthma surveillance can aid in the identification of children with possible undiagnosed asthma. Implementation of a geographic information systems framework can enhance the identification of demographic and physical environmental factors associated with possible undiagnosed asthma.