Confirmatory factor analyses of the ORTO 15-, 11- and 9-item scales and recommendations for suggested cut-off scores

  • Stephan Moller
  • Pragalathan Apputhurai
  • Simon R. KnowlesEmail author
Original Article
Part of the following topical collections:
  1. Orthorexia Nervosa



To explore the validity and recommend cut-off scores in an English-speaking sample for 9, 11, and 15-item versions of the ORTO measure for orthorexia, a proposed eating disorder characterised by a pathological obsession with consuming only ‘healthy’ foods.

Materials and methods

The sample comprised of 585 participants (82.4% female) who completed an online questionnaire containing the ORTO-15, Eating Attitudes test, Obsessive Compulsive Inventory Revised. A series of Confirmatory Factor Analyses were conducted to test model fit. Binary logistic linear regression and receiver-operating-characteristics (ROC) analyses were used to obtain cut-offs.

Results and conclusion

Results showed that none of the three published versions (9, 11, and 15-item) of the ORTO produced an acceptable model. Subsequent exploratory and confirmatory factor analyses yielded a seven-item version of the ORTO (ORTO-7) with a strong and stable factor structure. Analysis of cut-offs revealed that a cut-off score of equal or greater than 19 on the ORTO-7 represents probable orthorexia.

Level of evidence

Level V, descriptive study.


Orthorexia Scale validation Confirmatory factor analysis Disordered eating 


Author contributions

All authors identified on this manuscript have contributed equally to the study and provide approval for the final version of this manuscript.

Compliance with ethical standards

Conflict of interest

The authors declare that this research was conducted in the absence of any conflict of interest.

Ethical approval

All procedures performed in studies involving human participants were in accordance with the ethical standards of the institutional and/or national research committee and with the 1964 Helsinki declaration and its later amendments or comparable ethical standards.

Informed consent

Informed consent was obtained from all individual participants included in the study.


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Copyright information

© Springer International Publishing AG, part of Springer Nature 2018

Authors and Affiliations

  • Stephan Moller
    • 1
  • Pragalathan Apputhurai
    • 1
  • Simon R. Knowles
    • 1
    • 2
    • 3
    • 4
    • 5
    Email author
  1. 1.Faculty of Health Arts, and DesignSwinburne University of TechnologyMelbourneAustralia
  2. 2.Department of GastroenterologyRoyal Melbourne HospitalMelbourneAustralia
  3. 3.Department of GastroenterologyThe Alfred HospitalMelbourneAustralia
  4. 4.Department of Mental HealthSt Vincent’s HospitalMelbourneAustralia
  5. 5.University of MelbourneMelbourneAustralia

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