Socioeconomic gradients and mechanisms of chronic disease health literacy: the mediating role of preventive healthcare utilization in rural Shangdong, China

To explore the social determinants and underlying mechanisms of health literacy in managing chronic diseases, and to analyze how socioeconomic status (SES) influences it. This study, based on Shandong Province’s 2022 Health Literacy Surveillance Database, selected 2,826 residents from some, counties in Shandong eligible areas using multistage stratified cluster random sampling. It explored the social determinants of chronic disease health literacy using multiple linear regression, multiple logistic regression, interactive analysis and mediation analysis. Higher SES (High vs. Low: OR = 2.21, 95%CI: 1.68–2.91, P < 0.001; Medium vs. Low: OR = 1.36, 95%CI: 1.08–1.71, P = 0.009), elevated household income (Highest vs. Lowest category: OR = 2.58, 95%CI: 1.58–4.22, P < 0.001), and higher educational attainment (Bachelor’s vs. Primary: OR = 3.46, 95%CI: 2.06–5.81, P < 0.001) were positively associated with higher chronic disease literacy. However, patients specifically diagnosed with hypertension (OR = 2.27, 95%CI: 1.35–3.79), coronary heart disease (OR = 2.57, 95%CI: 1.14–5.81), or diabetes (OR = 2.37, 95%CI: 1.21–4.63) demonstrated significantly higher literacy levels. The preventive healthcare services (indirect effect = 0.017, 95% CI: 0.016–0.041, P < 0.001), changes in health behavior (indirect effect = 0.007, 95% CI: 0.002–0.020, P < 0.001), and frequency of physical examinations (indirect effect = 0.006, 95% CI: 0.004–0.015, P < 0.001) significantly mediated the relationship between SES and chronic disease literacy. Subgroup analysis showed that in the low SES group, women (OR = 0.60, 95% CI: 0.50–0.75, P < 0.001) and elders (OR = 0.70, 95% CI: 0.42–0.91, P = 0.001) had significantly lower chronic disease literacy than men and young participants. This study elucidates the multidimensional mechanisms by which SES impacts chronic disease health literacy and provides a scientific basis for developing targeted interventions.