Greek adaptation of the Teruel Orthorexia Scale (TOS) in adults from the Republic of Cyprus: A bidimensional model may not be universal

The Teruel Orthorexia Scale (TOS) is a 17-item instrument designed to assess distinct facets of Orthorexia Nervosa (ON) and Healthy Orthorexia (HO). While a bidimensional model of TOS scores has been supported in diverse national and linguistic groups, the psychometric properties of the TOS have not been previously assessed in Greek-speaking populations. To rectify this, we assessed the psychometric properties of a novel Greek translation of the TOS in a sample of adults from Cyprus. A total of 1248 respondents (710 women, 538 men) completed the Greek TOS, as well as previously validated measures of perfectionism, obsessive-compulsive symptomatology, eating restriction, negative affect, and appearance evaluation. Our results showed that a bidimensional model of the TOS had less-than-adequate fit when modelled using both confirmatory factor analysis and exploratory structural equation modeling (ESEM). Conversely, both exploratory factor analysis and ESEM supported extraction of a 3-factor model consisting of a HO facet and separate components of emotional orthorexia and cognitive-social orthorexia. This 3-factor model showed a lack of measurement bias (measurement invariance across gender identity and lack of differential item functioning as function of age and body mass index), but there were differences in latent factor means as function of respondent age and body mass index. The 3-factor model showed adequate evidence of construct validity, with the latent emotional orthorexia and cognitive-social orthorexia facets showing significant and moderate associations with the additional constructs measured in the survey. Broadly speaking, these findings support the psychometric properties of a 3-factor model of the Greek TOS, but also suggest that the bidimensional model of the TOS may not have universal applicability. We encourage further assessments of factorial validity in other national and linguistic contexts.