Background/Objectives: Body image self-perception has been associated with adverse mental health outcomes, but prospective evidence on its relationship with depression is limited and inconsistent. Objective: To examine the association between body image perception and incident depression in Spanish adults over a follow-up period, and whether these associations differ by sex.

Methods: This prospective cohort study included 15,774 Spanish university graduates free of depression at baseline (Retention rate 90.5%). Body image self-perception was assessed using Stunkard's Figure Rating Scale and categorized as adequate, underestimation, or overestimation according to body mass index. Incident depression was identified through biennial questionnaires over a median follow-up of 13.7 years. Cox proportional hazard models stratified by age and cohort were used to estimate Hazard Ratio (HR) and 95% Confidence interval (CIs), stratified by sex and progressively adjusted for sociodemographic factors, body mass index, lifestyle behaviors, dietary factors, sleep characteristics, and psychological traits.

Results: During follow-up (median follow-up: 13.7 years), 291 cases of incident depression occurred among men and 703 among women. Body image misperception was strongly associated with baseline body mass index and lifestyle characteristics, with distinct patterns by sex. However, no statistically significant association was observed between body image perception and incident depression in either men or women in fully adjusted models. Compared with adequate perception, adjusted HRs were 0.91 (95%CI: 0.64-1.29) for underestimation and 0.74 (95%CI: 0.46-1.20) for overestimation among men, and 1.06 (95%CI: 0.73-1.54) and 1.10 (95%CI: 0.88-1.38), respectively, among women. No significant sex-perception interaction was detected.

Conclusions/Recommendations: In this prospective cohort, body image perception was not independently associated with incident depression after accounting for body mass index and lifestyle factors. These findings suggest that body image perception may reflect underlying behavioral and sociocultural factors rather than constituting an independent risk factor for depression.