Factor Structure and Measurement Invariance Across Gender of the Eating Disorder Examination Questionnaire—Short Form in Italian Workers

Eating disorders (EDs) are complex conditions that can significantly affect health and productivity, yet their assessment in occupational settings remains underexplored. This study aimed to evaluate the psychometric properties of the Italian version of the Eating Disorder Examination Questionnaire–Short Form (EDE-QS) among 1,912 workers undergoing health surveillance. Using an Item Response Theory framework, we tested dimensionality, reliability, and measurement invariance across gender, applying a graded response model to assess item discrimination and threshold parameters. Results supported a unidimensional structure with excellent internal consistency (ω ≈ .95) and strong indices of factor score determinacy and construct replicability. Measurement invariance analyses indicated configural and metric invariance but not full scalar invariance, due to differential item functioning in a subset of items. Latent mean differences were small, with women scoring slightly higher than men, and associations with psychological, occupational, and health-related variables did not differ by gender. These findings indicate that the Italian EDE-QS is a reliable and valid instrument for rapid screening of ED symptoms in workplace contexts. However, gender-related item bias warrants cautious interpretation of specific behaviors, suggesting the need for tailored assessments to enhance diagnostic accuracy and inform preventive interventions.