Digital health literacy and disordered eating among adolescents: the chain mediating roles of physical activity and problematic social media use.

BACKGROUND: Digital environments may increase adolescents' vulnerability to disordered eating through misleading health information and problematic social media use. This study examined the association between digital health literacy and disordered eating, including the independent and serial indirect associations of physical activity and problematic social media use. METHODS: This cross-sectional study included 2,206 adolescents recruited from five secondary schools using purposive and convenience sampling. Participants had a mean age of 14.50 years (SD = 1.76). Digital health literacy, disordered eating, physical activity, and problematic social media use were assessed using validated scales. Correlation and bootstrap-based regression analyses were conducted to estimate the specific and serial indirect associations. RESULTS: Digital health literacy was negatively associated with disordered eating and problematic social media use and positively associated with physical activity. The total association between digital health literacy and disordered eating was -0.324 (95% CI [-0.365, -0.283]), including a direct association of -0.135 (95% CI [-0.177, -0.092]). Indirect associations were observed through physical activity (-0.098, 95% CI [-0.121, -0.077]), problematic social media use (-0.072, 95% CI [-0.089, -0.057]), and physical activity followed by problematic social media use (-0.019, 95% CI [-0.024, -0.015]). CONCLUSION: Digital health literacy was associated with disordered eating through independent and serial indirect associations involving physical activity and problematic social media use. These findings suggest the value of coordinated school- and family-based strategies integrating digital health literacy education, physical activity promotion, responsible social media use, and early identification of disordered eating.