Reliability and validity of the Japanese translation of the Eating Disorders Quality of Life (ED-QOL) scale for Japanese healthy female university undergraduate students and patients with eating disorders.

Background: The Eating Disorder Quality of Life (ED-QOL) scale is a 25-item self-report measure that assesses health-related quality of life (HRQoL) of eating-disorder patients. Although the ED-QOL is one of the most widely used questionnaires in many countries, no prior research has addressed the psychometric properties of the Japanese translation of the ED-QOL. Therefore, the aim of the present study was to assess its reliability and validity.

Methods: A total of 99 Japanese female eating disorder patients and 469 female healthy university undergraduate students completed the Japanese translation of the ED-QOL in addition to the Eating Attitudes Test-26 (EAT-26) and Eating Disorder Inventory-2 (EDI-2). The patient group consisted of 37 patients with anorexia nervosa restricting type (AN-R), 35 patients with binge-eating/purge type (AN-BP), and 27 patients with bulimia nervosa (BN). We performed confirmatory factor analyses on the ED-QOL subscales both for Japanese eating disorder patients and for healthy university undergraduate students. Reliability was assessed using internal consistency indicated by Cronbach alpha coefficients and convergent validity was assessed using Pearson's correlation coefficients. To assess group differences between the eating disorder patients and healthy university undergraduate students, Student's t-tests were conducted.

Results: The CFA showed that the CFI was .90 and RMSEA was .084 (90% confidence interval = .079-.088). The internal consistency of the ED-QOL varied from good to excellent. The EAT-26 total score and three subscales and the EDI-2 subscales had significant correlations with the ED-QOL global QOL score and four subscales. There were no significant correlations between the EDI-2 subscale "Body Dissatisfaction" and the ED-QOL subscales "Physical/Cognitive" and "Work/School". Eating disorder patients scored significantly higher than healthy university undergraduate students on all ED-QOL subscales and the global QOL score.

Conclusions: Based on this study, the Japanese translation of the ED-QOL can be regarded as reliable, valid, and functional for female eating-disorder patients and female healthy university undergraduate students.