Psychometric properties of the ORTO-R in a community-based sample of women and men from Poland

PURPOSE: Over the past two decades, orthorexia nervosa (ON) has been increasingly investigated. Recently, a new revision version of the ORTO-15, namely ORTO-R, was used. The main objective of the present study was to confirm the factor structure of Polish version of the ORTO-R for evaluating ON thoughts and behaviors. METHOD: In three studies, a total of 3081 participants was selected by random sampling through several universities and companies. In Study 1, we used original items of ORTO-15, in Study 2 we used both, the ORTO-15 items and the revised items from ORTO-R, and in Study 3 we used only the items from the ORTO-R. Confirmatory factor analysis was used for determining the factorial structure of the Polish version of the ORTO-R. We also assessed internal consistency and convergent and criterion validity of the ORTO-R. RESULTS: The model composed of the revised items (ORTO-R) was characterized of good convergent and criterion validity. Furthermore, ORTO-R appeared to be more internally consistent as compared to ORTO-15. CONCLUSION: The 6-item ORTO-R is valid and reliable method to assess orthorexic thoughts and behaviors among Polish-speaking population and could be applied in future research. Using revised version of the items is strongly preferred to using the items in their original ORTO-15 form.