Does Health Literacy Moderate Educational Disparities in Health-Related Quality of Life Among Cancer Survivors in South Korea?

Background: Educational disadvantage is associated with poorer health-related quality of life (HRQOL) among cancer survivors. Health literacy may influence this relationship, but its potential moderating role remains poorly understood. This study examined whether health literacy moderated the association between educational attainment and HRQOL among cancer survivors. Methods: This secondary analysis used nationally representative data from the 2024 Korea National Health and Nutrition Examination Survey. Participants were 380 adults aged ≥19 years with a self-reported physician diagnosis of cancer. Health literacy was assessed using the 10-item Health Literacy Index for the Community, and HRQOL was assessed using the EQ-5D. Complex-samples general linear models tested the interaction between educational attainment and health literacy, adjusting for age, sex, and comorbidity. Results: Higher health literacy was independently associated with better HRQOL (B = 0.006, 95% CI = 0.003 to 0.009, p < 0.001), whereas educational attainment was not independently associated with HRQOL. The overall education-by-health literacy interaction was significant (Wald F = 3.740, p = 0.013). The interaction was particularly evident among participants with middle school education (B = 0.011, 95% CI = 0.003 to 0.018, p = 0.006), whose predicted EQ-5D index scores increased as health literacy increased. Conclusions: These findings highlight health literacy as a potentially modifiable factor relevant to education-related disparities in cancer survivorship. Longitudinal and intervention studies are needed to determine whether improving health literacy can reduce these disparities.