Evidence of Validity, Invariance, and Reliability of the Body Image Dimension in the Body Investment Scale: A Study in Spanish University Students

Background: This study focused on the widely used Body Image subscale, a dimension of the Body Investment Scale developed by Orbach and Mikulincer in 1998. Specifically, we explored its psychometric properties and potential use for health promotion research among young Spanish university students. Method: A sample of 793 participants (75.28% female) aged 18–26 years (M = 20.68; SD = 2.13) completed the questionnaire and related variables. Results: A unidimensional structure was confirmed with a good fit, demonstrating gender- and age-invariance, along with robust internal consistency. The scale exhibited a significant association with self-esteem, life satisfaction, a sense of coherence, and psychological distress. Conclusions: The Body Image subscale can be considered unidimensional. The obtained factor solution provides a reliable, valid, and invariant measure across gender and age for assessing body feelings in Spanish university students. Therefore, the instrument can effectively investigate the relationship between body image and health-related behaviors. Additionally, it can serve as a valuable tool in designing effective health interventions for university students to prevent mental health conditions, such as eating disorders or suicidal behaviors.