Mediating effect of health literacy on the relationship between diabetes status and aerobic physical activity adherence among middle-aged Korean adults: a theory-based secondary analysis of the second year of the ninth Korea National Health and Nutri

Purpose: This study applied Orem’s self-care theory to examine differences in adherence to aerobic physical activity according to diabetes status among middle-aged adults and to evaluate the mediating effect of health literacy. By distinguishing between diabetes and prediabetes, the study aimed to reflect the stepwise nature of self-care demand while conceptualizing health literacy as a self-care agent. Methods: A secondary analysis was conducted using data from the second year of the ninth Korea National Health and Nutrition Examination Survey. The study included 2,781 adults aged 40-64 years. Variables were constructed based on Orem’s self-care theory. Complex sample hierarchical logistic regression and mediation analyses were conducted using SPSS version 28.0 and R version 4.4.2. Results: Among the participants, 14.3% had diabetes and 34.1% had prediabetes. Higher educational attainment and personal income were significantly associated with adherence to aerobic physical activity. Diabetes status was significantly associated with decreased adherence, whereas prediabetes status showed no significant association. Health literacy was positively associated with adherence. Mediation analysis indicated that health literacy partially mediated the negative effects of diabetes and prediabetes on adherence to aerobic physical activity. Conclusion: By empirically applying Orem’s self-care theory, this study identified differences in adherence to aerobic physical activity according to diabetes status and demonstrated the critical role of health literacy as a self-care agent. These findings suggest that nursing interventions for diabetes prevention and management should adopt stratified approaches based on health status, with an emphasis on enhancing health literacy and strengthening self-care behaviors.