Psychometric Evaluation of the Brief MBSRQ-AS15 Across Sexes: Structural Validity, Scalar Invariance, and the Male Overweight Preoccupation Caveat

Assessing body image efficiently requires brief, psychometrically sound instruments. This study evaluated the 15-item short-form Appearance Scales of the Multidimensional Body-Self Relations Questionnaire (MBSRQ-AS15) to determine its structural validity, internal consistency, and cross-sex measurement invariance. A community sample of 1776 Greek adults (899 men, 877 women; mean age = 33.68 ± 9.89 years) completed the MBSRQ-AS15 alongside validation measures (Rosenberg Self-Esteem Scale [RSES], Eating Attitudes Test-26 [EAT-26]). Sex-specific Confirmatory Factor Analysis (CFA) and Multi-Group CFA evaluated factor structure and scalar invariance. The five-factor model showed excellent fit in women (CFI = 0.984, RMSEA = 0.070) but poorer fit in men (CFI = 0.946, RMSEA = 0.105). Multi-group analysis established full scalar invariance (ΔCFI = 0.000). Internal consistency was robust in women (ω = 0.681–0.843) and most male subscales, except Overweight Preoccupation (OWPREOC) (ω = 0.477). Convergent validity was supported, though OWPREOC correlated weaker with eating attitudes in men (r = 0.348) than women (r = 0.555; z = −5.52, p < 0.001). To facilitate preliminary empirical research, sample-based reference percentiles for community comparisons are provided. Overall, the MBSRQ-AS15 offers a practical brief option for body image research, though its psychometric performance remains distinctly stronger in women than in men. While scalar invariance enables mean comparisons, male weight preoccupation scores require cautious interpretation due to potential confounding with muscularity goals.