Associations Among Educational Attainment, Health Literacy, and Diet Quality Among Korean Adults

Background: Accumulating evidence has demonstrated disparities in dietary quality according to educational attainment. This study examined associations among educational attainment, health literacy (HL), and dietary quality. Methods: This cross-sectional study included a nationally representative sample of 9943 adults. Educational attainment was categorized into four groups: elementary school or lower, middle school, high school, and college or higher. HL was assessed using the Health Literacy Index for the Community (HLIC) scale, and dietary quality was assessed using the Korean Healthy Eating Index (KHEI). Linear regression models were used to determine the association between educational attainment and KHEI. Mediation analysis was conducted to examine the indirect association of educational attainment with KHEI score through the HLIC, expressed as indirect association. Beta (β) coefficients and 95% confidence intervals (CIs) were computed. Results: Of the participants, 15.2% had completed elementary school or lower, 10.1% middle school, 33.2% high school, and 41.5% had attained college education or higher. While an inverse association was observed between educational attainment and KHEI score, the direction of the association reversed to positive after adjustment for age. In the fully adjusted model, using elementary school or lower as the reference group, middle school, high school, and college or higher education were associated with 2.46-point (95% CI, 1.30–3.61), 2.43-point (95% CI, 1.44–3.42), and 2.86-point (95% CI, 1.81–3.92) higher KHEI scores, respectively. The adjusted β coefficients (95% CI) for the indirect association were β = 0.19 (95% CI, 0.10–0.30) for middle school, β = 0.40 (95% CI, 0.24–0.57) for high school, and β = 0.53 (95% CI, 0.31–0.76) for college or higher, accounting for 7.70%, 16.61%, and 18.48% of the total association, respectively. Conclusions: This study showed an indirect association between educational attainment and dietary quality via HL. However, longitudinal studies should be conducted to elucidate causal mediation.