Impact of health literacy on socioeconomic and racial differences in health in an elderly population

Background: Differences in health literacy levels by race and education are widely hypothesized to contribute to health disparities, but there is little direct evidence. Objective: To examine the extent to which low health literacy exacerbates differences between racial and socioeconomic groups in terms of health status and receipt of vaccinations. Design: Retrospective cohort study. Participants (Or Patients Or Subjects): Three thousand two hundred and sixty noninstitutionalized elderly persons enrolling in a Medicare managed care plan in 1997 in Cleveland, OH; Houston, TX; South Florida; and Tampa, FL. Measurements: Dependent variables were physical health SF-12 score, mental health SF-12 score, self-reported health status, receipt of influenza vaccine, and receipt of pneumococcal vaccine. Independent variables included health literacy, educational attainment, race, income, age, sex, chronic health conditions, and smoking status. Results: After adjusting for demographic and health-related variables, individuals without a high school education had worse physical and mental health and worse self-reported health status than those with a high school degree. Accounting for health literacy reduced these differences by 22% to 41%. Black individuals had worse self-reported health status and lower influenza and pneumococcal vaccination rates. Accounting for health literacy reduced the observed difference in self-reported health by 25% but did not affect differences in vaccination rates. Conclusions: We found that health literacy explained a small to moderate fraction of the differences in health status and, to a lesser degree, receipt of vaccinations that would normally be attributed to educational attainment and/or race if literacy was not considered.