Portuguese version of the Body Appreciation Scale-2 for Children (BAS-2C): Psychometric evaluation and measurement of invariance across sex

Body appreciation, a central aspect of positive body image, recently started to capture the attention of the scientific community as a potential determinant of well-being. However, little is known about onset and early identification in both males and females, as studies on this subject in childhood are still scarce, due in part to a dearth of validated instruments. Therefore, the main purpose of this study is to examine the psychometric properties and sex invariance of a Portuguese version of the Body Appreciation Scale-2 for Children (BAS-2C; Halliwell et al., 2017). We also explored the relationship between the BAS-2C and body mass index z-scores (BMIz). Participants were 328 children, ages 9-to-11 years (50.9% girls). Confirmatory factor analysis indicated that the one-dimensional factor structure had adequate fit, but sex invariance was not supported. Differential item functioning analysis revealed that boys and girls respond differently to item #9, which assesses body comfort. BAS-2C scores evidenced internal consistency and convergent validity with quality of life, healthy eating habits, and body size dissatisfaction. BMIz showed a low ability to predict body appreciation. This study brings support for the use of the BAS-2C in Portuguese-speaking children, but caution is warranted in comparing BAS-2C scores across sexes.