Prevalence and predictors of orthorexia nervosa among German students using the 21-item-DOS.

Purpose: Orthorexia nervosa (ON) describes the constant pathological preoccupation with "healthy" nutrition. The current results regarding the prevalence of ON differ widely possibly because of invalid measurement tools. This study aimed to investigate ON prevalence in a sample of German students and to examine age, gender, semester, and nutritional knowledge as potential predictors of ON by comparing nutrition science (NS) with economics (ES) students.

Methods: A total of 446 university students participated in the survey (NS 188, ES 268). ON was determined using the 21-item-DOS, which is a well-constructed, validated, and reliability-tested questionnaire. Age, gender, and semester were also assessed.

Results: Of the total sample, 3.3 % were classified as having ON and 9.0 % were at risk of developing ON. Older students scored significantly higher on the subscale "avoidance of additives" compared with younger students and students of lower semester suffered significantly more often from ON than students of higher semester. In addition, comparing field of study showed no significant difference in the prevalence of ON or the risk of developing ON between female NS and ES students. However, mean values for the three DOS subscales were higher among female NS students, albeit far below values indicating pathological behavior.

Conclusions: The prevalence of ON appears to be low in this sample of German university students. Female NS students do not seem to have higher prevalence of ON or risk of developing ON.