Body weight misperception and academic performance in Chinese adolescents (2007-2022): the mediating role of loneliness.

Introduction: Body weight misperception is increasingly prevalent among adolescents, yet the association between weight misperception and academic performances is unclear. This study aims to examine the association among weight misperception and academic performances among Chinese adolescents and estimate the mediating effect of loneliness on this association. Methods: This repeated cross-sectional study uses data of adolescents aged 13-19 years, collected from the Ningbo Youth Risk Behavior Surveys from 2007 to 2022. Data of anthropometric, demographic, weight perception, mood, and academic performance information were collected via self-reported questionnaires. Multivariate logit regression is used to investigate the association between weight misperception and academic performance. A generalized structural equation model is used to assess the mediating effect of loneliness on this association. Results: The sample sizes for each wave were 921, 909, 1,555, and 2,690. Adolescents with overestimation of body weight were significantly associated with higher odds of having poor academic performances for both girls (OR: 1.23, 95% CI: 1.03-1.46) and boys (OR: 1.45, 95% CI: 1.18-1.77). Specifically, body weight overestimation was significantly associated with higher odds of loneliness for girls (OR: 1.28, 95% CI: 1.05-1.56) and boys (OR: 1.40, 95% CI: 1.11-1.75), while loneliness was significantly associated with poorer academic performances for girls (OR: 1.34, 95% CI: 1.05-1.71) and boys (OR: 1.31, 95% CI: 1.09-1.59). Loneliness played a mediating role in the association between overestimation of body weight and poor academic performances, with indirect effects of 58.19 and 55.85% for girls (OR: 1.69, 95% CI: 1.14-2.24) and boys (OR: 1.81, 95% CI: 1.28-2.34), respectively. Discussion: Overestimation of body weight is associated with poorer academic performances in Chinese adolescents, mediated by loneliness. This finding suggests that family and school-based health education and psychological interventions, such as education on body image, targeted mental health consulting, mutual aid networks, fostering inclusive classroom, and family-school collaboration, should be encouraged to the well-being of adolescents.