摘要：Objectives. We estimated the extent to which socioeconomic status (SES) gradients in adult asthma and rhinitis outcomes can be explained by home and neighborhood environmental factors. Methods. Using survey data for 515 adults with either asthma or rhinitis, or both, we examined environmental mediators of SES associations with disease severity, using the Severity of Asthma Scale, and health-related quality of life (HRQL), using the Rhinasthma Scale. We defined SES on the basis of education and household income. Potential environmental mediators included home type and ownership, exposures to allergens and irritants, and a summary measure of perceived neighborhood problems. We modeled each outcome as a function of SES, and controlled for age, gender, and potential mediators. Results. Gradients in SES were apparent in disease severity and HRQL. Living in a rented house partially mediated the SES gradient for both severity and HRQL ( P < .01). Higher perceived levels of neighborhood problems were associated with poorer HRQL and partially mediated the income–HRQL relationship ( P < .01). Conclusions. Differences in home and neighborhood environments partially explained associations of SES with adult asthma and rhinitis outcomes. Socioeconomic status (SES) gradients in health, in which lower SES is associated with poorer health status and outcomes, have been observed for many chronic illnesses, including asthma and rhinitis. 1–6 Asthma and rhinitis have prevalence estimates of 10% to 20% in the adult population, 6,7 with large impacts on morbidity, health care utilization, and quality of life in the United States and globally. 7–9 A recent analysis of National Health Interview Survey data found that a substantial portion of the racial/ethnic differences in asthma prevalence could be attributed to SES. 10 The specific mechanisms by which SES affects asthma and rhinitis outcomes, however, have not been fully elucidated. The conceptual model underlying the present study posits that there are multiple pathways through which socioeconomic differences can account for variations in disease outcomes. Such pathways could include a differential burden of environmental exposures, differences in health access, or differences in capacity for optimal disease self-management because of education or other resources. Thus, this model holds that SES is a key explanatory variable upon which health outcomes are dependent, and that SES can work through different sets of intermediate factors that can be characterized as distinct “pathways.” In the current study, we focused on one pathway conceptualized in this model: the extent to which observed SES gradients in adult asthma and rhinitis can be explained by environmental factors in the home or surrounding neighborhood. Environmental exposures in the home that have been associated with asthma and rhinitis outcomes include irritants such as tobacco smoke and combustion products from heating and cooking sources, 11–13 and allergens from sources such as dust mites, pets, cockroaches, rodents, and mold. 14–21 Asthma morbidity and rhinitis symptoms have also been associated with ambient air pollution, 22,23 residential proximity to vehicular traffic, 24,25 occupational exposures, 26–28 neighborhood characteristics, 29,30 and stressful life events. 31 Many of these risk factors may be more common among individuals with lower SES because of a lack of control over the home environment (for example, because of renting rather than owning), a paucity of resources to make modifications to the home, living in less desirable neighborhoods, or exposure to other kinds of adverse environmental exposures. Because of consistent differences seen in prevalence and outcomes of these conditions by SES, the observation that environmental exposures associated with these outcomes also vary with SES, 32 and the large burden of these conditions, asthma and rhinitis are important conditions in which to investigate the role of environmental factors in mediating the SES gradient in health disparities.
