Serial mediation of body image and cognitive self-perceptions in adolescents: Evidence from the Cogni-Action Project

Objective This study aimed to explore the serial mediating roles of body self-image and cognitive self-perception in the relationship between body mass index (BMI) and objective cognitive performance among adolescents, while considering potential sex differences. Methods This cross-sectional study included 1296 adolescents (50% girls) aged 10–14 years (median: 12 [11−13] years). Body self-image (mediator 1, M1) was assessed using the seven-item Children's Body Image Scale (CBIS), and cognitive self-perception (mediator 2, M2) was measured on a 1–10 scale. Standardized BMI values were used, and cognitive performance was evaluated through a neurocognitive battery assessing attention, working memory, and problem-solving. Three serial mediation models were analyzed, adjusting for sex, cardiorespiratory fitness, maturation, and the school vulnerability index. Results In the overall sample, M1 and M2 mediated the relationship between BMI and cognitive performance. Specifically, M2 mediated memory (standardized beta coefficient [B] = 0.0069; 95% confidence interval [CI] = 0.0008 to 0.0152), whereas M1 mediated problem-solving (B = 0.0489; 95% CI = 0.0149 to 0.0827). Both M1 and M2 jointly mediated problem-solving (B = −0.0048; 95% CI = −0.0107 to −0.0001). In sex specific analyses, boys presented similar patterns to the total sample for memory, while girls exhibited significant mediation effects in problem-solving. Conclusion Body self-image and cognitive self-perception play distinct mediating roles in the BMI-cognition relationship, differing across cognitive domains and between sexes. These findings emphasize the need for tailored educational and health interventions that foster positive self-perceptions to enhance adolescents' cognitive development and well-being.