Date of Award


Document Type


Degree Name

Doctor of Philosophy (PhD)


Health Outcomes and Policy Research

Research Advisor

James E. Bailey, MD


Lawrence M. Brown, PhD Carolyn Graff, PhD Gretchen Norling. Holmes, PhD George Relyea, MS


Introduction: Asthma affects 24.6 million people in the United States, and AfricanAmericans share a disproportionate burden of the disease. African-Americans have a higher prevalence of asthma, worse asthma control, higher hospitalization rates, and higher asthma mortality rates African-Americans are also more likely to have low health literacy. Low health literacy has been linked to increased use of emergency care, increased hospitalization, decreased use of preventive services, poorer medication adherence, poorer interpretation of prescription labels, nutrition labels, and health messages, and poorer health outcomes. Consequently, health literacy is one of the modifiable individual factors that contributes to asthma disparities among African-Americans.

Methods: This study was a sub-study of a larger clinical trial. An explanatory sequential mixed methods approach was used in this study. In the initial quantitative phase, 99 participants completed cross-sectional surveys. Numeracy and health literacy (print literacy) were evaluated, and participants were dichotomized into having adequate or limited numeracy and adequate or low print literacy. Primary outcomes were asthma control (ACQ) and asthma related quality of life (AQLQ-S). Mediating factors examined were asthma self-efficacy and asthma selfmanagement knowledge. Following the quantitative phase, four participants were chosen to complete semi-structured interviews. Interview questions focused on information seeking behaviors, patient-provider communication, and self-management behaviors. Chi-square, t-tests, and Wilcoxon Mann-Whitney test were used to compare participants across health literacy levels. The Preacher and Hayes method of bootstrapping multiple mediator analysis was used in this study. Both total and specific indirect effects were examined using 5,000 bootstrap samples to calculate 95% bias corrected confidence intervals. SAS 9.3 was used to analyze quantitative data. QDA Miner was used to perform Interpretative Phenomenological Analysis of the interview data.

Results: Bivariate analysis indicated that adequate numeracy but not adequate print literacy was significantly associated with increased quality of life and asthma control. Mediation analysis found that print literacy was not associated with asthma outcomes, and self-efficacy and knowledge did not mediate the relationship. Numeracy was associated with quality of life, and this relationship was partially mediated by self-efficacy and knowledge. Numeracy was not associated with asthma control. Three themes emerged from qualitative analysis including “information received vs. information desired,” “trial and error,” and “expectations of the patient-provider relationship.” Lastly, quantitative and qualitative results were integrated to make meta-inferences.

Discussion/Conclusion: Results indicate that numeracy, but not print literacy, is associated with asthma outcomes. This finding is consistent with previous literature in this area. Self-efficacy and asthma knowledge are not primary mediators between health literacy and asthma outcomes, and other mediators (i.e., patient-provider communication and patient activation) may have a larger impact. Culture plays an important role in health literacy and patient-provider communication. Future research should examine other mediators besides selfefficacy and asthma knowledge, the role of numeracy in asthma self-management, and the intersection of culture and health literacy in relation to health outcomes.




One year embargo expired December 2014