Social media exposure by content type and orthorexia nervosa tendencies: multivariable and sex-stratified analyses in adults

Orthorexia nervosa (ON), characterized by a pathological preoccupation with dietary purity, has been increasingly linked to social media use. This cross-sectional study examined associations between four social media content categories—self-optimization and health, appearance and social comparison, entertainment, and informational and hobby content—and ON tendencies in adults (n = 2,435), using multivariable linear regression and sex-stratified analyses with the ORTO-11. Participants classified as having elevated ON tendency according to the sample-derived threshold (n = 586) were older, more likely to be female, and more highly educated; BMI did not differ between groups. In the fully adjusted model (R²=0.042), self-optimization and health content was the strongest correlate of lower Orto-11 scores (β=−0.45, 95%CI − 0.62 to − 0.28, p < 0.001). Informational and hobby content was also significantly associated with lower scores (β=−0.38, 95%CI − 0.67 to − 0.08, p = 0.013). Appearance-oriented and entertainment content were not independently associated with ON tendencies after adjustment. Sex-stratified analyses showed that the association with self-optimization content was consistent across sexes (males: β=−0.45, p = 0.01; females: β=−0.48, p < 0.001), with no significant sex × content interaction. Effect sizes were negligible (Cliff’s delta:0.006–0.125) and the model explained only 4% of variance, indicating limited practical magnitude. Given the cross-sectional design, causal inference is precluded and reverse causation cannot be excluded. These findings suggest that content type may be more informative than usage duration in characterizing the social media–ON relationship, with health-optimization content emerging as a modest but consistent correlate of ON tendencies across sexes. © The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature 2026.