| Despite promulgation of national and international guidelines on the effective management of pediatric asthma, asthma-related morbidity among urban children remains disproportionately high. While there is ample evidence of persistent health disparities by race/ethnicity and income, there is a lack of understanding of the causal mechanism(s) that underlie these disparities. The lack of conceptualization of the relevant causal pathway(s) presents a challenge for the implementation of interventions designed to mitigate the burden of asthma in urban communities.;Epidemiologic studies have demonstrated that asthma-related morbidity has both strong socioeconomic and demographic antecedents, as measured by race and class, as well as strong physical environmental antecedents, in particular, prolonged exposure to ambient air pollution. Due to the non-random process associated with neighborhood selection, analyses of the impact of place on health outcomes frequently rely on observational data. Moreover, since social and environmental exposures coincide frequently in urban communities, the identifiability of the direct causal effects of each of these distinct groups of exposures presents a methodological challenge.;To address these issues, two main analyses were conducted. First, a geographic information system (GIS) was implemented to explore the association of ecological-level covariates, derived from the 2000 United States Census and regional land-use data, and individual level covariates, obtained from a school-based asthma case-identification program, with neighborhood asthma prevalence and individual asthma-case status. Results from analyses in which neighborhood was defined as census-tract indicated that percent of residents who spoke English as a second language, percent of residents born in the United States, percent of unemployed mothers, percent of children below the federal poverty line and presence of mixed housing land use were associated positively and significantly with neighborhood asthma prevalence. For the individual-level analysis, increases in the percent of two parent households and percent of unemployed single fathers were associated with decreased odds of individual asthma case status, though neither association was statistically significant. Results from analyses in which neighborhood was defined as a ¼ mile residential buffer indicated that thirteen separate land use designations as well as median household income for Latino households were negatively and significantly associated with asthma prevalence. The percentage of residents who spoke English only was the only covariate associated positively with buffer-level asthma prevalence. The odds of individual case status was associated positively with percentage of children who spoke English only (OR: 1.01, 95% CI: 1.006, 1.012); median household income for Latino households was associated with decreased odds of individual case status (OR: 0.999, 95% CI: 0.999, 0.999).;In the second analysis, marginal structural models (MSM), a class of causal inference models, were utilized to determine the causal effect of exposure to traffic exhaust on asthma prevalence and asthma-related morbidity among public school children in Oakland, CA. Marginal structural models can be used to analyze observational data as if they were obtained under randomization of exposure(s). Under certain assumptions, this method controls for confounding and allows for a derivation of a causal estimate of effect vis-a-vis comparison of two counterfactuals: asthma outcomes had the entire community been exposed to traffic exhaust to asthma outcomes had the entire community not been exposed to traffic exhaust. The estimates derived from these analyses are average population-level causal effects. Such estimates are of particular utility to community-oriented policy development and intervention design. Results from the marginal structural model analysis indicated that there is a non-significant causal effect of residence within 500 feet of a closed access freeway on current asthma (OR: 1.025, 95% CI: 0.998, 1.052), and a positive and significant causal effect of residence near the freeway on outpatient emergency care for children with diagnosed asthma (OR: 1.472, 95% CI: 1.416, 1.531). (Abstract shortened by UMI.)... |
