Abstract
INTRODUCTION: The college period represents a pivotal stage for establishing long-term health behaviors. Grounded in the COM-B (Capability, Opportunity, Motivation-Behavior) model, this study constructs a comprehensive behavioral explanatory framework: positioning eHealth literacy as Capability, social support as Opportunity, and social responsibility as core Motivation to predict healthy lifestyles (Behavior). It further examines how this mechanism is moderated by major, mental health, and sense of hope. METHODS: From May to June 2022, a cross-sectional survey was conducted involving 4,036 students recruited from six universities in Shandong Province, China, using stratified cluster sampling. Validated scales were administered to assess healthy lifestyle, eHealth literacy, social support, social responsibility, mental health, and sense of hope. Multiple linear regression combined with the Bootstrap method was used to explore variable mediation, and Bootstrap was further applied to test moderation effects. RESULTS: A total of 4,036 participants were included in this study, among whom 1,811 were male (44.9%) and 2,225 were female (55.1%). In terms of grade distribution, there were 2,216 lower-grade students (55.0%) and 1,820 upper-grade students (45.0%). The mean score for healthy lifestyles was 3.95 (±0.74). Social responsibility emerged as the strongest predictor (β = 0.449, 95%CI [0.413, 0.466]) and was found to partially mediate the relationships of both eHealth literacy and social support with healthy lifestyles. Furthermore, major negatively moderated the relationship between eHealth literacy and healthy lifestyles (β = -0.127, p < 0.001), while mental health status negatively moderated the relationship between social support and healthy lifestyles (β = -0.087, p < 0.001). In contrast, sense of hope positively moderated the relationship between social responsibility and healthy lifestyles (β = 0.040, p < 0.001). DISCUSSION: Social responsibility is not only related to the healthy lifestyle of college students, but also plays a mediating role between electronic health literacy, social support, and healthy lifestyle. Therefore, colleges and universities should focus on cultivating students' sense of social responsibility, systematically improve their health literacy, create a supportive campus environment, and enhance students' psychological capital and sense of hope. These multi-level measures, when working together, will help to establish a sustainable mechanism for promoting a healthy lifestyle among college students.