Screening-positive subclinical eating disorder symptoms and associated factors among high school students: a cross-sectional study

Background Subclinical eating disorder (SCED) symptoms are common among adolescents and may be associated with adverse psychological and behavioral outcomes. However, evidence on screening-positive SCED symptoms and associated factors among high school students remains limited. Identifying these factors may support early screening and prevention. Methods In December 2023, a stratified random cluster sampling method was used to recruit students from 12 high schools in Yangzhou, Jiangsu Province, China. Data were collected using a self-developed general information questionnaire, the Eating Disorder Examination Questionnaire 6.0 (EDE-Q 6.0), the Ma Body Figure Scale, the Children’s Depression Inventory–Short Form (CDI-S), the Spence Children’s Anxiety Scale–Short Version (SCAS-S), the National Mental Health Literacy Questionnaire, and the Pittsburgh Sleep Quality Index. BMI was classified using the WHO 2007 age- and sex-specific BMI-for-age reference for participants younger than 19 years, with adult WHO BMI cut-offs used for participants aged 19 years or older. Generalized estimating equations (GEE) with school as the clustering variable were used to examine factors associated with screening-positive SCED symptoms. Results A total of 2,681 high school students were included in the analysis, of whom 645 (24.1%) screened positive for SCED symptoms. In the school-clustered GEE model, female sex (OR = 1.351, 95% CI: 1.109–1.645), overweight (OR = 3.418, 95% CI: 2.632–4.439), obesity (OR = 7.740, 95% CI: 5.939–10.089), positive body image misperception (OR = 4.280, 95% CI: 3.533–5.184), higher depressive symptom scores (OR per 1-SD increase = 1.454, 95% CI: 1.297–1.630), higher anxiety symptom scores (OR per 1-SD increase = 1.387, 95% CI: 1.269–1.516), and poor sleep quality (OR = 1.393, 95% CI: 1.121–1.733) were associated with higher odds of screening-positive SCED symptoms. Adequate mental health literacy was associated with lower odds (OR = 0.609, 95% CI: 0.506–0.734). Conclusion Approximately one-quarter of the participating high school students screened positive for SCED symptoms. Screening-positive SCED symptoms were associated with weight status, body image misperception, depressive and anxiety symptom severity, sleep quality, and mental health literacy. These findings support multidimensional school-based screening and health education while recognizing that the EDE-Q threshold identifies a screening-defined condition rather than a clinical diagnosis.