The Polish version of the Düsseldorf Orthorexia Scale (PL-DOS) and its comparison with the English version of the DOS (E-DOS)

PURPOSE: Although orthorexia nervosa, the fixation on health-conscious eating behaviour, was first described in the 90 s, there is no clear understanding whether existing ON measures are appropriate for its assessment. The objectives of the present study were to: (1) examine the psychometric properties of the Polish version of the DOS (PL-DOS) and to compare the PL-DOS with the English version of the DOS (E-DOS) as well as (2) evaluate the prevalence of ON among Polish university students and compare the prevalence rates of ON among Polish and U.S. students. METHODS: Four-hundred and twelve students (77.2% female) with a mean age of 24.62 years (SD = 6.86) participated in the present study. All participants completed the Polish version of the Düsseldorf Orthorexia Scale (PL-DOS), the Eating Habits Questionnaire (EHQ) and the Eating Disorder Inventory (EDI). RESULTS: Reliability analysis for the PL-DOS showed strong internal consistency with a Cronbach’s alpha coefficient of 0.840 and a coefficient omega of 0.840, 95% CI [0.808, 0.866]. Significant correlation coefficients were found between the PL-DOS and all subscales of the EHQ. Confirmatory factor analysis showed that the one-factor model had poor fit. Polish students had an ON prevalence rate of 6.6%, lower than that of U.S. students (8%). CONCLUSIONS: Our findings validate the use of the PL-DOS as an appropriate ON measure for a Polish population. LEVEL OF EVIDENCE: Level V, cross-sectional descriptive study.