Chinese version of the Nine-Item Avoidant/Restrictive Food Intake Disorder Scale in patients with inflammatory bowel disease: a test of reliability and validity

Objective  To test the reliability and validity of the Chinese version of the Nine-Item Avoidant/Restrictive Food Intake Disorder Scale (NIAS) in patients with inflammatory bowel disease (IBD).

Methods  Based on convenience sampling method, 304 patients from the Treatment Center for Inflammatory Bowel Disease of two Grade Ⅲ Level hospitals A in Jiangsu Province were selected as the research objects, and they were investigated by a general information questionnaire, NIAS, and the Satisfaction with Food-Related Life (SWFL). Item analysis (discrimination analysis, correlation coefficient) and reliability analysis of the total scale and subscales (Cronbach's α coefficient) were performed. Exploratory factor analysis, confirmatory factor analysis, criterion-related validity, convergent validity, and discriminant validity were used to test the validity of the scale.

Results  The Chinese version of NIAS contained 9 items, including 3 subscales of picky eating, appetite and fear; the confirmatory factor analysis indicated a good construct validity in 3-factor modelχ²/df=2.340, root mean square error of approximation (RMSEA)=0.078, standardized root mean square residual (SRMR)=0.046, incremental fit index (IFI)=0.969, comparative fit index (CFI)=0.969, normed fit index (NFI)=0.948, goodness of fit index (GFI)=0.951, the Tucker-Lewis index (TLI)=0.951; the correlation coefficient between the total score of the Chinese version of NIAS and the SWFL scale was -0.353, indicating a strong correlation; the aggregated validity CR values for each dimension of the scale were 0.821 to 0.855, and the AVE values were 0.606 for appetite, 0.621 for picky eating, and 0.664 for fear. The total Cronbach's α coefficient of the Chinese version of the NIAS scale was 0.82, and the Cronbach's α coefficients for dimensions of picky eating, appetite and fear were 0.87, 0.71 and 0.92 respectively, indicating the Chinese version of the NIAS scale had good internal consistency and stability.

Conclusion  The Chinese version of the NIAS scale has good reliability and validity, and can be used to evaluate avoidant and restrictive food intake disorder behaviors in IBD patients.