Mediators of the socioeconomic gradient in outcomes of adult asthma and rhinitis

Abstract

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.

FIGURE 1—

Mean scores at each level of family income and education for (a) severity of asthma and (b) rhinasthma HRQL: University of California, San Francisco Asthma Rhinitis Cohort, 2008–2009. Note. AA = associate degree; HRQL = health-related quality of life; HS = high school. Mean ±SD severity of asthma score = 9.6 ±6.1. Higher scores indicate greater severity. Mean rhinasthma HRQL score = 31.4 ±21.4. Higher scores indicate poorer HRQL. *P < .05 for comparison with highest level of income or education.