Journal of Human Nutrition and Dietetics
NUTRITIONAL SCIENCES Validation of the Eating Disorder Examination Questionnaire: an online version C. W. Chan & S. F. Leung School of Nursing, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong
Keywords Eating Disorder Examination Questionnaire, Hong Kong, online, university students, validation. Correspondence C. W. Chan, School of Nursing, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong. Tel.: +852 2766 4147 Fax: +852 2364 9663 E-mail: [email protected] How to cite this article Chan C.W. & Leung S.F. (2015) Validation of the Eating Disorder Examination Questionnaire: an online version. J Hum Nutr Diet. 28, 659–665 doi:10.1111/jhn.12275
Abstract Background: Internet-based interventions can facilitate an anonymous environment for the management of eating disorders and there is a need for online assessment tools to be readily available. The present study aimed to validate an online version of the Eating Disorder Examination Questionnaire (EDE-Q) and to compare the goodness-of-fit of five models of EDE-Q data, using a sample of university students in Hong Kong. Methods: The EDE-Q data were collected online from 310 Hong Kong university students. Confirmatory factor analysis was used to compare the validity of the original four-factor EDE-Q with that of the three-factor, twofactor, one-factor and brief one-factor models. The superior model was further examined for scale reliability, convergent validity and construct validity using contrast-group comparisons. Results: The brief one-factor model consisting of eight Weight and Shape Concern items was the only model to provide an acceptable fit to the data. Estimations of internal consistency and scale validity were conducted using contrast-group comparisons and convergent validity, with satisfactory results. Conclusions: The brief one-factor model was the only one among the alternate models that provided good fit to the data. The brief model is promising for use in research and has good practical application because the model was satisfactorily tested in terms of internal consistency, ability to discriminate between genders, and good association with other measures of similar constructs. By validating an online version of the EDE-Q using a university sample with a cultural background different from Western culture, the present study complements findings from previous research on the EDE-Q.
Introduction Incidences of eating disorders (EDs) are increasing in both Asian and Western countries (Lee, 2000; Huon et al., 2002; Makino et al., 2004; Hay et al., 2008). Changes in Asia, such as resulting from the import of both Western fashion and beauty ideals, the rapid expansion of fast food restaurants, an increased consumption of high fat foods and decreased physical activity (Lee and Lee, 2000; Xie et al., 2006), have contributed to body image concern in young individuals and an increased risk for developing weight and eating disorders (Lee et al., ª 2014 The British Dietetic Association Ltd.
1996; Lee and Lee, 2000; Huon et al., 2002). Among the young, studies have identified that university students are a high-risk population for eating disorder symptomatology (Yeh et al., 2009; Thomas et al., 2010; Quick & ByrdBredbenner, 2013). The risk can be related to an increased demand for academic achievement, high stress and anxiety, dating relationships, peer influence, struggle with self-concept, and role and identity changes (HesseBiber & Marino, 1991; Nichols et al., 2009). Given the surging risk of eating disorders among university students, early assessment and intervention should be undertaken to improve this situation. 659
Validate online EDE-Q
The Internet has become a major source of health information for young people and provides a viable means of delivering eating disorder assessment and interventions. Numerous preventive interventions conducted through the Internet have shown that they can improve body image dissatisfaction, eating disorder patterns and shape or weight preoccupations, and decrease the onset of eating disorders in high-risk university students (Zabinski et al., 2001a,b; Taylor et al., 2006). Furthermore, Internet-based interventions can reduce the obstacles to treatment, promote cost-effectiveness, and create a comfortable and anonymous environment to enable individuals with eating disorders to engage in selfmanagement (Forkner-Dunn, 2003; Ybarra & Eaton, 2005). With the emerging theme of Internet-based interventions, there is a need for online assessment tools to be readily available for the management of EDs. The Eating Disorder Examination Questionnaire (EDE-Q) (Fairburn & Beglin, 1994) is a self-report questionnaire version of the Eating Disorder Examination interview (Cooper & Fairburn, 1987), designed to assess the key attitudes and behavioural features of EDs. Such tools are considered to represent the pre-eminent eating disorder assessments (Wilson, 1993). The reliability and validity of the scale for assessing eating disorders were revealed in a recent systematic review, although replicating the original factor structures was not supported and inconclusive findings with diverse groups were noted; additional research to broaden the generalisability of the findings has been explicitly suggested (Byrne et al., 2010; Allen et al., 2011; Berg et al., 2012). There is also a concern as to whether the EDE-Q developed in a western population will be valid for online use by different cultural and diverse groups. Therefore, the present study aimed to examine the psychometric properties of the EDE-Q when administered online because no study has been performed to validate the online version using a sample of Hong Kong university students. We examined the factor structure, reliability and construct validity using contrast-group comparisons and convergent validity with the SCOFF Questionnaire and Body Shape Questionnaire (BSQ). Specifically for factor structure, we aimed to extend the results of previous studies (Fairburn & Beglin, 1994; Pennings & Wojciechowski, 2004; Peterson et al., 2007; Wade et al., 2008; Becker et al., 2009; Allen et al., 2011) and compared the goodness-of-fit of five models of EDE-Q: A four-factor model of the EDE-Q (original model) (Fairburn & Beglin, 1994; Allen et al., 2011) corresponding to the original subscales: dietary restraint, eating concern, weight concern and shape concern.
•
660
C. W. Chan and S. F. Leung
•
A three-factor model (Peterson et al., 2007) consisting of dietary restraint, eating concern, and collapsing weight and shape concern subscales. A two-factor model (Becker et al., 2009) consisting of dietary restraint and collapsing eating, weight and shape concern items. A one-factor model (Pennings & Wojciechowski, 2004) consisting of all EDE-Q subscale items. A brief one-factor model (Wade et al., 2008) consisting of eight items from the weight and shape concern subscales.
• • •
Materials and methods Participants The present study was approved by a University Ethics Committee in Hong Kong. The participants comprised university students studying for a bachelor’s degree, associate degree or high diploma at University Grants Committee funded or self-funded institutions in Hong Kong. They were recruited during the period from September to November 2013 through personal approach at different university campuses and social network sampling using strategies such as Facebook, Whatsapp and electronic promotional posters. A website called the ‘Smart ehealth’ programme was developed for the present study. A study information sheet and consent form were included on the ‘Member Registration’ webpage, and voluntary participants were asked to register as a member before they could gain access to a set of online self-administered questionnaires. The online registration procedure elicits demographic information, including gender, age, body weight and height, nationality, country of residence, marital status, occupation, educational level, name of university, university degree, major study discipline and history of medical and psychological disorders. The online questionnaires included the EDE-Q, the SCOFF Questionnaire and the BSQ. They could be completed at any time based on the participant’s convenience. The online submission was anonymous to enhance credible responses, as well as to avoid the social desirability, appearance-related pressure and self-consciousness typically associated with face-toface interactions (Zabinski et al., 2003). Autonomic messages would be shown to alert the participants if the questionnaires submitted were not completed; this minimised missing responses. To reduce the rate of participant drop-out, reminders were also sent to those who failed to attempt the questionnaires after registration. Upon completion of each questionnaire, individuals were provided with automatic feedback, such as self-assessment scores and information concerning these scores. For security purposes, the demographic information and data provided by the participants were protected by password ª 2014 The British Dietetic Association Ltd.
C. W. Chan and S. F. Leung
and a special Web maintenance service. Only researchers had access to the collected data, thus privacy and confidentiality were assured. Measures The EDE-Q is a 28-item self-report questionnaire that focuses on symptoms that occurred within the previous 28 days (Fairburn & Beglin, 1994). Six items in the EDEQ identify the behavioural features of eating disorders in terms of frequency or days the behaviour occurred, and 22 items assess the severity of eating disorder symptoms on four subscales: dietary restraint, eating concern, weight concern and shape concern. The items on each subscale are rated on a seven-point rating scale (0–6). A mean score of 4–6 on any subscale is interpreted as a high likelihood of its clinical significance. A global score for the EDE-Q can be obtained by summing up the scores of all four subscales and dividing the resulting total by the number of subscales (i.e. four) to show the overall severity of the eating disorder psychopathology. The scale reliability of the EDE-Q in terms of internal consistency and test–retest, together with various psychometric data, has been reported in previous studies (Fairburn & Beglin, 1994; Luce & Crowther, 1999; Allen et al., 2011). Regarding convergent validity, the SCOFF Questionnaire and BSQ were used to correlate with the EDE-Q. The SCOFF Questionnaire is a five-item quick screening tool for checking out the core features of anorexia nervosa and bulimia nervosa (Morgan et al., 1999). Validation studies of the SCOFF Questionnaire have been conducted and it was concluded to be effective as a screening tool in its British and Chinese versions (Morgan et al., 1999; Luck et al., 2002; Leung et al., 2009). The SCOFF Questionnaire score is obtained by summing the item scores. A score ≥2 in the SCOFF Questionnaire indicates a high risk of having an eating disorder. The BSQ (Dowson & Henderson, 2001) consists of 14 items that measure the level of body image dissatisfaction; it has good test–retest reliability, as well as concurrent and discriminant validity (Cooper & Fairburn, 1987; Rosen et al., 1996). The scale score is obtained by summing the item scores. A higher score indicates a higher level of body image dissatisfaction. Statistical analysis Confirmatory factor analysis (CFA) with ANALYSIS OF MOMENT STRUCTURES, version 20 (IBM Corporation, 2011), was used to compare the goodness-of-fit statistics of the five proposed models. As the standard criteria for model testing, goodness-of-fit statistics were used to determine the best model among the proposed alternate models. A ª 2014 The British Dietetic Association Ltd.
Validate online EDE-Q
model could be considered as a good fit if the Normed Fit Index (NFI), Incremental Fit Index (IFI), TuckerLewis Index (TLI) and Comparative Fit Index (CFI) are ≥ 0.90 and the root mean square error of approximation is below 0.05 (0.70 being considered acceptable. For contrast-group comparisons (comparisons between genders) and convergent validity, the Mann–Whitney U-test and Spearman’s correlation were used. P < 0.05 was considered statistically significant. Results The study sample consisted of 310 university participants from 12 institutions, of whom 54.2% (n = 168) were female and 45.8% (n = 142) were male. The mean (SD) age of the participants was 20.75 (1.81) years (range 18– 26 years). The mean (SD) body mass index (BMI) of the female participants was 20.05 (2.96) kg m–2 (range 13.89–34.80 kg m–2). Of the females, 31.1% were underweight (
NUTRITIONAL SCIENCES Validation of the Eating Disorder Examination Questionnaire: an online version C. W. Chan & S. F. Leung School of Nursing, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong
Keywords Eating Disorder Examination Questionnaire, Hong Kong, online, university students, validation. Correspondence C. W. Chan, School of Nursing, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong. Tel.: +852 2766 4147 Fax: +852 2364 9663 E-mail: [email protected] How to cite this article Chan C.W. & Leung S.F. (2015) Validation of the Eating Disorder Examination Questionnaire: an online version. J Hum Nutr Diet. 28, 659–665 doi:10.1111/jhn.12275
Abstract Background: Internet-based interventions can facilitate an anonymous environment for the management of eating disorders and there is a need for online assessment tools to be readily available. The present study aimed to validate an online version of the Eating Disorder Examination Questionnaire (EDE-Q) and to compare the goodness-of-fit of five models of EDE-Q data, using a sample of university students in Hong Kong. Methods: The EDE-Q data were collected online from 310 Hong Kong university students. Confirmatory factor analysis was used to compare the validity of the original four-factor EDE-Q with that of the three-factor, twofactor, one-factor and brief one-factor models. The superior model was further examined for scale reliability, convergent validity and construct validity using contrast-group comparisons. Results: The brief one-factor model consisting of eight Weight and Shape Concern items was the only model to provide an acceptable fit to the data. Estimations of internal consistency and scale validity were conducted using contrast-group comparisons and convergent validity, with satisfactory results. Conclusions: The brief one-factor model was the only one among the alternate models that provided good fit to the data. The brief model is promising for use in research and has good practical application because the model was satisfactorily tested in terms of internal consistency, ability to discriminate between genders, and good association with other measures of similar constructs. By validating an online version of the EDE-Q using a university sample with a cultural background different from Western culture, the present study complements findings from previous research on the EDE-Q.
Introduction Incidences of eating disorders (EDs) are increasing in both Asian and Western countries (Lee, 2000; Huon et al., 2002; Makino et al., 2004; Hay et al., 2008). Changes in Asia, such as resulting from the import of both Western fashion and beauty ideals, the rapid expansion of fast food restaurants, an increased consumption of high fat foods and decreased physical activity (Lee and Lee, 2000; Xie et al., 2006), have contributed to body image concern in young individuals and an increased risk for developing weight and eating disorders (Lee et al., ª 2014 The British Dietetic Association Ltd.
1996; Lee and Lee, 2000; Huon et al., 2002). Among the young, studies have identified that university students are a high-risk population for eating disorder symptomatology (Yeh et al., 2009; Thomas et al., 2010; Quick & ByrdBredbenner, 2013). The risk can be related to an increased demand for academic achievement, high stress and anxiety, dating relationships, peer influence, struggle with self-concept, and role and identity changes (HesseBiber & Marino, 1991; Nichols et al., 2009). Given the surging risk of eating disorders among university students, early assessment and intervention should be undertaken to improve this situation. 659
Validate online EDE-Q
The Internet has become a major source of health information for young people and provides a viable means of delivering eating disorder assessment and interventions. Numerous preventive interventions conducted through the Internet have shown that they can improve body image dissatisfaction, eating disorder patterns and shape or weight preoccupations, and decrease the onset of eating disorders in high-risk university students (Zabinski et al., 2001a,b; Taylor et al., 2006). Furthermore, Internet-based interventions can reduce the obstacles to treatment, promote cost-effectiveness, and create a comfortable and anonymous environment to enable individuals with eating disorders to engage in selfmanagement (Forkner-Dunn, 2003; Ybarra & Eaton, 2005). With the emerging theme of Internet-based interventions, there is a need for online assessment tools to be readily available for the management of EDs. The Eating Disorder Examination Questionnaire (EDE-Q) (Fairburn & Beglin, 1994) is a self-report questionnaire version of the Eating Disorder Examination interview (Cooper & Fairburn, 1987), designed to assess the key attitudes and behavioural features of EDs. Such tools are considered to represent the pre-eminent eating disorder assessments (Wilson, 1993). The reliability and validity of the scale for assessing eating disorders were revealed in a recent systematic review, although replicating the original factor structures was not supported and inconclusive findings with diverse groups were noted; additional research to broaden the generalisability of the findings has been explicitly suggested (Byrne et al., 2010; Allen et al., 2011; Berg et al., 2012). There is also a concern as to whether the EDE-Q developed in a western population will be valid for online use by different cultural and diverse groups. Therefore, the present study aimed to examine the psychometric properties of the EDE-Q when administered online because no study has been performed to validate the online version using a sample of Hong Kong university students. We examined the factor structure, reliability and construct validity using contrast-group comparisons and convergent validity with the SCOFF Questionnaire and Body Shape Questionnaire (BSQ). Specifically for factor structure, we aimed to extend the results of previous studies (Fairburn & Beglin, 1994; Pennings & Wojciechowski, 2004; Peterson et al., 2007; Wade et al., 2008; Becker et al., 2009; Allen et al., 2011) and compared the goodness-of-fit of five models of EDE-Q: A four-factor model of the EDE-Q (original model) (Fairburn & Beglin, 1994; Allen et al., 2011) corresponding to the original subscales: dietary restraint, eating concern, weight concern and shape concern.
•
660
C. W. Chan and S. F. Leung
•
A three-factor model (Peterson et al., 2007) consisting of dietary restraint, eating concern, and collapsing weight and shape concern subscales. A two-factor model (Becker et al., 2009) consisting of dietary restraint and collapsing eating, weight and shape concern items. A one-factor model (Pennings & Wojciechowski, 2004) consisting of all EDE-Q subscale items. A brief one-factor model (Wade et al., 2008) consisting of eight items from the weight and shape concern subscales.
• • •
Materials and methods Participants The present study was approved by a University Ethics Committee in Hong Kong. The participants comprised university students studying for a bachelor’s degree, associate degree or high diploma at University Grants Committee funded or self-funded institutions in Hong Kong. They were recruited during the period from September to November 2013 through personal approach at different university campuses and social network sampling using strategies such as Facebook, Whatsapp and electronic promotional posters. A website called the ‘Smart ehealth’ programme was developed for the present study. A study information sheet and consent form were included on the ‘Member Registration’ webpage, and voluntary participants were asked to register as a member before they could gain access to a set of online self-administered questionnaires. The online registration procedure elicits demographic information, including gender, age, body weight and height, nationality, country of residence, marital status, occupation, educational level, name of university, university degree, major study discipline and history of medical and psychological disorders. The online questionnaires included the EDE-Q, the SCOFF Questionnaire and the BSQ. They could be completed at any time based on the participant’s convenience. The online submission was anonymous to enhance credible responses, as well as to avoid the social desirability, appearance-related pressure and self-consciousness typically associated with face-toface interactions (Zabinski et al., 2003). Autonomic messages would be shown to alert the participants if the questionnaires submitted were not completed; this minimised missing responses. To reduce the rate of participant drop-out, reminders were also sent to those who failed to attempt the questionnaires after registration. Upon completion of each questionnaire, individuals were provided with automatic feedback, such as self-assessment scores and information concerning these scores. For security purposes, the demographic information and data provided by the participants were protected by password ª 2014 The British Dietetic Association Ltd.
C. W. Chan and S. F. Leung
and a special Web maintenance service. Only researchers had access to the collected data, thus privacy and confidentiality were assured. Measures The EDE-Q is a 28-item self-report questionnaire that focuses on symptoms that occurred within the previous 28 days (Fairburn & Beglin, 1994). Six items in the EDEQ identify the behavioural features of eating disorders in terms of frequency or days the behaviour occurred, and 22 items assess the severity of eating disorder symptoms on four subscales: dietary restraint, eating concern, weight concern and shape concern. The items on each subscale are rated on a seven-point rating scale (0–6). A mean score of 4–6 on any subscale is interpreted as a high likelihood of its clinical significance. A global score for the EDE-Q can be obtained by summing up the scores of all four subscales and dividing the resulting total by the number of subscales (i.e. four) to show the overall severity of the eating disorder psychopathology. The scale reliability of the EDE-Q in terms of internal consistency and test–retest, together with various psychometric data, has been reported in previous studies (Fairburn & Beglin, 1994; Luce & Crowther, 1999; Allen et al., 2011). Regarding convergent validity, the SCOFF Questionnaire and BSQ were used to correlate with the EDE-Q. The SCOFF Questionnaire is a five-item quick screening tool for checking out the core features of anorexia nervosa and bulimia nervosa (Morgan et al., 1999). Validation studies of the SCOFF Questionnaire have been conducted and it was concluded to be effective as a screening tool in its British and Chinese versions (Morgan et al., 1999; Luck et al., 2002; Leung et al., 2009). The SCOFF Questionnaire score is obtained by summing the item scores. A score ≥2 in the SCOFF Questionnaire indicates a high risk of having an eating disorder. The BSQ (Dowson & Henderson, 2001) consists of 14 items that measure the level of body image dissatisfaction; it has good test–retest reliability, as well as concurrent and discriminant validity (Cooper & Fairburn, 1987; Rosen et al., 1996). The scale score is obtained by summing the item scores. A higher score indicates a higher level of body image dissatisfaction. Statistical analysis Confirmatory factor analysis (CFA) with ANALYSIS OF MOMENT STRUCTURES, version 20 (IBM Corporation, 2011), was used to compare the goodness-of-fit statistics of the five proposed models. As the standard criteria for model testing, goodness-of-fit statistics were used to determine the best model among the proposed alternate models. A ª 2014 The British Dietetic Association Ltd.
Validate online EDE-Q
model could be considered as a good fit if the Normed Fit Index (NFI), Incremental Fit Index (IFI), TuckerLewis Index (TLI) and Comparative Fit Index (CFI) are ≥ 0.90 and the root mean square error of approximation is below 0.05 (0.70 being considered acceptable. For contrast-group comparisons (comparisons between genders) and convergent validity, the Mann–Whitney U-test and Spearman’s correlation were used. P < 0.05 was considered statistically significant. Results The study sample consisted of 310 university participants from 12 institutions, of whom 54.2% (n = 168) were female and 45.8% (n = 142) were male. The mean (SD) age of the participants was 20.75 (1.81) years (range 18– 26 years). The mean (SD) body mass index (BMI) of the female participants was 20.05 (2.96) kg m–2 (range 13.89–34.80 kg m–2). Of the females, 31.1% were underweight (
