Validation of the inflexible eating questionnaire in a large sample of Chinese adolescents: psychometric properties and gender-related differential item functioning

Abstract

The aim of this study was to provide preliminary psychometric evidence for the Chinese version of the Inflexible Eating Questionnaire (C-IEQ) among a large sample of Chinese adolescents. For testing the psychometric properties of the C-IEQ, a total of 2241 (Mage\u2009=\u200913.91 years; 46.4% boys) adolescents from mainland China responded to the survey. Confirmatory factor analysis (CFA) was used to examine the factor structure of the C-IEQ. Measurement invariance by gender was examined by both multi-group CFA and differential item functioning (DIF). Convergent validity of the C-IEQ was assessed via examining the correlations between the C-IEQ scores and theoretically related constructs (e.g., orthorexia nervosa symptomatology, eating disorder symptomatology, and body image inflexibility). The unidimensional structure with correlated errors of the C-IEQ showed good model fit (χ2\u2009=\u20091674.05, df\u2009=\u200944, p\u2009<\u20090.001; CFI\u2009=\u20090.93; TLI\u2009=\u20090.91; RMSEA\u2009=\u20090.13; SRMR\u2009=\u20090.06). The C-IEQ had an adequate internal consistency (α\u2009=\u20090.89) and demonstrated strong measurement invariance across genders. Moreover, the scores of the C-IEQ showed significant correlations with theoretically correlated constructs: orthorexia nervosa symptomatology (girls; r\u2009=\u20090.53 p\u2009<\u20090.001, boys; r\u2009=\u20090.45 p\u2009<\u20090.001), eating disorder symptomatology (girls; r\u2009=\u20090.32 p\u2009<\u20090.001, boys; r\u2009=\u20090.25 p\u2009<\u20090.001) body image inflexibility (girls; r\u2009=\u20090.41 p\u2009<\u20090.001, boys; r\u2009=\u20090.36 p\u2009<\u20090.001), suggesting good convergent validity of the C-IEQ. The C-IEQ showed good psychometric properties in a sample of Chinese adolescents and can be used in future studies to assess eating-specific psychological inflexibility among Chinese adolescents. Level V, cross-sectional descriptive study.