Item response theory-based validation of a short form of the Eating Behavior Scale for Japanese adults

Obesity has become a serious social problem in industrialized countries in recent years. Clinically, although the evaluation of dietary behavior abnormalities is as important as any method of risk assessment for obesity, almost all the existing scales with many items may have numerous practical clinical difficulties. In this study, we aimed to prepare a short questionnaire to assess the dietary behavior abnormalities related to obesity. A total of 1032 individuals aged 20 to 59 years participated in the present study. Using item response theory (IRT), we selected the items for a short version from among 30 items of Sakata Eating Behavior Scale (EBS), which is widely used in Japan. As a result of the IRT-based analysis on the original 30-item version, 7 items were adopted as the short version. The correlation between the total score of the original EBS and the EBS short form was extremely high (r = 0.93, P = .001). In examining the criterion validity, for all participants (n = 1032), male (n = 516), and female (n = 516), the correlation coefficients between the total score of the EBS short form and body mass index (BMI) were r = 0.26, r = 0.28, and r = 0.28, respectively. The results of the receiver operating characteristic analysis was performed with obesity BMI > 25 kg/m as a dependent variable, the value of the area under the curve in the ROC was significantly higher in the 7-item version than in the total score of the original items (P = .0005). In conclusion, the 7-item EBS short form was created. Furthermore, it was found that the EBS short form is a reliable and valid measure that can be used as an indicator of obesity in both clinical and research settings.