Is the prevalence of orthorexia nervosa in an Australian university population 6.5%?

PURPOSE: To survey Australian adults at a Sydney university about: their tendencies towards the proposed health food eating disorder, orthorexia nervosa (and to estimate the prevalence of this condition), their eating behaviours, and their body image.

METHODS: A pilot, cross-sectional and descriptive online survey was conducted on staff and students at the University of New South Wales, Sydney. The primary outcome was the score on the most commonly used and validated measure of orthorexic behaviours, the ORTO-15. The point prevalence of orthorexia nervosa was estimated using the ORTO-15 cut-off score of < 35. Other outcomes were the Eating Attitudes Test-26 and the Body Shape Questionnaire-34.

RESULTS: In the sample of 92 Australian adults recruited at a university, there was a point prevalence rate for orthorexia nervosa of 21% when using the ORTO-15 cut-off value of < 35. If criteria A and B of proposed diagnostic criteria for the condition were also taken into consideration (i.e. someone with orthorexia nervosa would display disordered healthy eating tendencies; as well as were: underweight, or had marked concern with their body shape, or had significant impairment of functioning in work life or social life), the true prevalence rate could be considered to be 6.5%.

CONCLUSIONS: Using the ORTO-15 tool alone may overestimate the true prevalence of orthorexia nervosa. Further research into the accurate diagnosis and treatment of orthorexia nervosa is needed.

LEVEL OF EVIDENCE: Level V, descriptive study.