The ORTO-15 is a commonly used screening instrument for symptoms of Orthorexia Nervosa (ON), an obsessive overconcern with healthy eating. However, its limitations have been evidenced in several published factorial models. We analyzed the psychometric properties of seven different ORTO-15 factorial models using data from Brazilian adult participants (n = 1455; 71.4% women; M age = 29.5, SD = 8.9 years) from the country’s five macro-regions who answered online questions for sample characterization and completed the Portuguese version of the ORTO-15 containing 15 items. We tested the fit of each model separately, analyzing data for men and women with separate confirmatory factor analysis, and using the Weighted Least Squares Mean and Variance Adjusted estimation method and goodness-of-fit indices. We also calculated the average variance extracted and the alpha ordinal and omega coefficients to analyze the convergent validity and reliability of the factors. None of the models tested presented adequate properties of validity and reliability. Although we found some acceptable reliability coefficients, they do not guarantee the validity of the data. Future investigators should be cautious when choosing the ORTO-15 for ON screening.
AlvarengaM. S.MartinsM. C. T.SatoK. S. C. J.VargasS. V. A.PhilippiS. T.ScagliusiF. B. (2012). Orthorexia nervosa behavior in a sample of Brazilian dietitians assessed by the Portuguese version of ORTO-15. Eating and Weight Disorders: EWD, 17(1), e29–e35. https://doi.org/10.1007/BF03325325
2.
American Psychiatric Association [APA]. (2022). Diagnostic and statistical manual of mental disorders - DSM-5-TR (5 ed.). American Psychiatric Association. https://doi.org/10.1176/appi.books.9780890425787
3.
ArusogluG.KabakçiE.KöksalG.MerdolT. K. (2008). Orthorexia nervosa and adaptation of ORTO-11 into Turkish. Türk Psikiyatri Dergisi, 19(3), 283–291.
4.
BarradaJ. R.MeuleA. (2024). Orthorexia nervosa: Research based on invalid measures is invalid. Journal of Global Health, 14, Article 03007. https://doi.org/10.7189/jogh.14.03007
5.
BarradaJ. R.RonceroM. (2018). Bidimensional structure of the orthorexia: Development and initial validation of a new instrument. Anales de Psicología, 34(2), 283–291. https://doi.org/10.6018/analesps.34.2.299671
6.
BarthelsF.MeyerF.PietrowskyR. (2015). Die Düsseldorfer Orthorexie Skala–Konstruktion und evaluation eines fragebogens zur erfassung ortho-rektischen Ernährungsverhaltens. Zeitschrift für Klinische Psychologie und Psychotherapie, 44(2), 97–105. https://doi.org/10.1026/1616-3443/a000310
BrownT. A. (2015). Confirmatory factor analysis for applied research (2nd ed.). The Guilford Press.
9.
ByrneB. M. (2001). Structural equation modeling with amos: Basic concepts, applications and programming. Mahwah, NJ: Lawrence Erlbaum Associates.
10.
CenaH.BarthelsF.CuzzolaroM.BratmanS.Brytek-MateraA.DunnT.VargaM.MissbachB.DoniniL. M. (2019). Definition and diagnostic criteria for orthorexia nervosa: A narrative review of the literature. Eating and Weight Disorders: EWD, 24(2), 209–246. https://doi.org/10.1007/s40519-018-0606-y
11.
CohenR. J.SwerdlikM. E.SturmanE. D. (2014). Testagem e avaliação psicológica: introdução a testes e medidas (8). AMGH.
12.
DamásioB. F.BorsaJ. C. (2017). Manual de desenvolvimento de instrumentos psicológicos (1). Vetor.
13.
da SilvaW. R.NevesA. N.DonofreG. S.BratmanS.TeixeiraP. C.CamposJ. A. D. B. (2022). Conceptualizing and evaluating the healthy orthorexia dimension. In PatelV. B.PreedyV. R. (Eds.), Eating disorders. Springer Nature. https://doi.org/10.1007/978-3-030-67929-3_87-1
14.
Dell'OssoL.CarpitaB.MutiD.CremoneI. M.MassimettiG.DiademaE.GesiC.CarmassiC. (2018). Prevalence and characteristics of orthorexia nervosa in a sample of university students in Italy. Eating and Weight Disorders: EWD, 23(1), 55–65. https://doi.org/10.1007/s40519-017-0460-3
15.
de SouzaA. N.AlexandreN. M. C.GuirardelloE. B. (2017). Propriedades psicométricas na avaliação de instrumentos: Avaliação da confiabilidade e da validade. Epidemiologia e servicos de saude: revista do Sistema Unico de Saude do Brasil, 26(3), 649–659. https://doi.org/10.5123/S1679-49742017000300022
16.
de SouzaQ. J. O. V.RodriguesA. M. J. (2014). Comportamento de risco para ortorexia nervosa em estudantes de nutrição. Jornal Brasileiro de Psiquiatria, 63(3), 200–204. https://doi.org/10.1590/0047-2085000000026
17.
DoniniL. M.BarradaJ. R.BarthelsF.DunnT. M.BabeauC.Brytek-MateraA.CenaH.CeroliniS.ChoH.CoimbraM.CuzzolaroM.FerreiraC.ale.GrammatikopoulouM. G.HallitS.HåmanL.HayP.JimboM.LassonC.LombardoC. (2022). A consensus document on definition and diagnostic criteria for orthorexia nervosa. Eating and Weight Disorders: EWD, 27(8), 3695–3711. https://doi.org/10.1007/s40519-022-01512-5
18.
DoniniL. M.MarsiliD.GrazianiM. P.ImbrialeM.CannellaC. (2004). Orthorexia nervosa: A preliminary study with a proposal for diagnosis and an attempt to measure the dimension of the phenomenon. Eating and Weight Disorders - Studies on Anorexia, Bulimia and Obesity, 9(2), 151–157. https://doi.org/10.1007/bf03325060
19.
DoniniL. M.MarsiliD.GrazianiM. P.ImbrialeM.CannellaC. (2005). Orthorexia nervosa: Validation of a diagnosis questionnaire. Eating and Weight Disorders: EWD, 10(2), e28–e32. https://doi.org/10.1007/BF03327537
20.
DunnT. J.BaguleyT.BrunsdenV. (2014). From alpha to omega: A practical solution to the pervasive problem of internal consistency estimation. British Journal of Psychology, 105(3), 399–412. https://doi.org/10.1111/bjop.12046
21.
DunnT. M.GibbsJ.WhitneyN.StarostaA. (2017). Prevalence of orthorexia nervosa is less than 1 %: data from a US sample. Eating and Weight Disorders: EWD, 22, 185–192. https://doi.org/10.1007/s40519-016-0258-8
22.
FornellC.LarckerD. F. (1981). Evaluating structural equation models with unobservable variables and measurement error. Journal of Marketing Research, 18(1), 39–50. https://doi.org/10.1177/002224378101800104
23.
GadermannA. M.GuhnM.ZumboB. D. (2012). Estimating ordinal reliability for likert-type and ordinal item response data: A conceptual, empirical, and practical guide. Pratical Assessment, Research & Evaluation, 17(3), 1–13. https://doi.org/10.7275/n560-j767
24.
HairJ. F.JrBlackW. C.BabinB. J.AndersonR. E. (2019). Multivariate data analysis (C. L. EMEA. 8a ed.). Boston, MA: Cengage.
25.
HuL.BentlerP. M. (1999). Cutoff criteria for fit indexes in covariance structure analysis: Conventional criteria versus new alternatives. Structural Equation Modeling: A Multidisciplinary Journal, 6(1), 1–55. https://doi.org/10.1080/10705519909540118
26.
LorenzonL. F. L.MinossiP. B. P.PegoloG. E. (2020). Ortorexia nervosa e imagem corporal em adolescentes e adultos [Orthorexia nervosa and body image in adolescents and adults]. Jornal Brasileiro de Psiquiatria, 69(2), 117–119. https://doi.org/10.1590/0047-2085000000266
MeuleA. (2023). Progress in research on orthorexia nervosa is still hampered by the use of the ORTO–15 and its modifications. Mental Health Science, 1(3), 163–166. https://doi.org/10.1002/mhs2.29
29.
MeuleA.HolzapfelC.BrandlB.GreetfeldM.Hessler-KaufmannJ. B.SkurkT.QuadfliegN.SchleglS.HaunerH.VoderholzerU. (2020). Measuring orthorexia nervosa: A comparison of four self-report questionnaires. Appetite, 146, 104512. https://doi.org/10.1016/j.appet.2019.104512
30.
MissbachB.HinterbuchingerB.DreiseitlV.ZellhoferS.KurzC.KonigJ. (2015). When eating right, is measured wrong! A validation and critical examination of the ORTO-15 questionnaire in German. PLoS One, 10(8), Article e0135772. https://doi.org/10.1371/journal.pone.0135772
31.
MitrofanovaE.PummellE.MartinelliL.PetrócziA. (2021). Does ORTO-15 produce valid data for “orthorexia nervosa”? A mixed-method examination of participants interpretations of the fifteen items. Eating and Weight Disorders: EWD, 26(3), 897–909. https://doi.org/10.1007/s40519-020-00919-2
32.
NiedzielskiA.Kazmierczak-WojtasN. (2021). Prevalence of orthorexia nervosa and its diagnostic tools-A literature review. International Journal of Environmental Research and Public Health, 18(10), 5488. https://doi.org/10.3390/ijerph18105488
33.
OberleC. D.SamaghabadiR. O.HughesE. M. (2017). Orthorexia nervosa: Assessment and correlates with gender, BMI, and personality. Appetite, 108, 303–310. https://doi.org/10.1016/j.appet.2016.10.021
34.
OliveiraM. F.MaglioniA. B. R. R.de MoraisB. A. B.ale.SerafimL. H. M.GanenA. d. P. (2021). Relação entre comportamentos de risco para ortorexia nervosa, mídias sociais e dietas em estudantes de nutrição. Saúde e pesquisa, 14(Supl. 1), 1–15. https://doi.org/10.17765/2176-9206.2021v14Supl.1.e9469
35.
Parra-FernandezM. L.Rodríguez-CanoT.Onieva-ZafraM. D.Perez-HaroM. J.Casero-AlonsoV.Munoz CamargoJ. C.Notario-PachecoB. (2018a). Adaptation and validation of the Spanish version of the ORTO-15 questionnaire for the diagnosis of orthorexia nervosa. PLoS One, 13(1), Article e0190722. https://doi.org/10.1371/journal.pone.0190722
36.
Parra-FernandezM. L.Rodríguez-CanoT.Perez-HaroM. J.Onieva-ZafraM. D.Fernandez-MartinezE.Notario-PachecoB. (2018b). Structural validation of ORTO-11-ES for the diagnosis of orthorexia nervosa, Spanish version. Eating and Weight Disorders: EWD, 23(6), 745–752. https://doi.org/10.1007/s40519-018-0573-3
37.
PenaforteF. R. O.BarrosoS. M.AraújoM. E.JapurC. C. (2018). Ortorexia nervosa em estudantes de nutrição: Associações com o estado nutricional, satisfação corporal e período cursado. Jornal Brasileiro de Psiquiatria, 67(1), 18–24. https://doi.org/10.1590/0047-2085000000179
38.
PontesJ. B.MontagnerM. I.MontagnerM. A. (2014). Ortorexia nervosa: Adaptação cultural do ORTO-15. DEMETRA: Alimentação, Nutrição & Saúde, 9(2), 533–548. https://doi.org/10.12957/demetra.2014.8576
39.
RamacciottiC. E.PerroneP.ColiE.BurgalassiA.ConversanoC.MassimettiG.Dell’OssoL. (2011). Orthorexia nervosa in the general population: A preliminary screening using a self-administered questionnaire (ORTO-15). Eating and Weight Disorders: EWD, 16(2), e127–e130. https://doi.org/10.1007/BF03325318
40.
RogozaR.DoniniL. M. (2021). Introducing ORTO-R: A revision of ORTO-15 - Based on the re-assessment of original data. Eating and Weight Disorders: EWD, 26(3), 887–895. https://doi.org/10.1007/s40519-020-00924-5
41.
SilvaW. R.MarmolC. H. C.NevesA. N.MarocoJ.CamposJ. A. D. B. (2021). A Portuguese adaptation of the Teruel Orthorexia Scale and a test of its utility with Brazilian young adults. Perceptual and Motor Skills, 128(5), 2052–2074. https://doi.org/10.1177/00315125211029240
42.
SouzaH. M. A. V.do CarmoA. S.dos SantosL. C. (2021). The Brazilian version of the DOS for the detection of orthorexia nervosa: Transcultural adaptation and validation among dietitians and nutrition college students. Eating and Weight Disorders: EWD, 26(8), 2713–2725. https://doi.org/10.1007/s40519-021-01143-2
43.
VargaM.ThegeB. K.Dukay-SzabóS.TúryF.FurthE. F. (2014). When eating healthy is not healthy: Orthorexia nervosa and its measurement with the ORTO-15 in Hungary. BMC Psychiatry, 14(59), 59. https://doi.org/10.1186/1471-244X-14-59
44.
ZumboB. D.GadermannA. M.ZeisserC. (2007). Ordinal versions of coefficients alpha and theta for likert rating scales. Journal of Modern Applied Statistical Methods, 6(1), 21–29. https://doi.org/10.22237/jmasm/1177992180
