Orthorexia can hide for a long time, as it is based on the pursuit of health and the rightful desire to follow the rules of proper nutrition. It is a model that we should all strive for - only the determination with which people at risk of illness begin to follow it is unhealthy.
Orthorexia rates vary from 6% to 60% in the general post-population to as much as 90% in risk groups, including students [12]. The reason for such large discrepancies is the use of different tools with different psychometric properties (e.g. BOT, ORTO-15), the adoption of different cut-off points for the diagnosis of ON, as well as possible methodological errors. For example, many studies using the BOT or ORTO-15 test indicate a significant incidence of orthorexic behavior among dieticians, doctors, and students of dietetics, medicine, and related disciplines [6-9].
However, the ON study conducted among German students using the BOT test did not reveal significant differences between students of dietetics and students of economics in terms of pathological eating behavior [13]. Significantly lower incidence rates of orthorexia were obtained also in the population of Spanish students when constructing the ORTO-15 questionnaire, indicating that the pathological nature of nutritional health behavior is manifested by a small percentage of students [14].
There are also differences in the incidence of orthorexia among men and women. Some studies indicate a predominance of women [15-20], while others indicate a predominance of males [6,16], and others do not show significant differences [12, 16-21]. The latest survey of Brytek-Matera among over 400 people indicates that the Polish version of the ORTO-15 test is reliable and a valuable tool to study the obsessive attitude to health and proper nutrition in the Polish population of women and men [16-20].
Other studies have also observed a link between orthorexia and healthy lifestyles and groups that adhere to all health-promoting principles. Agopyan [22] conducted a study to establish a link between orthorexia and body composition of female students at the University of Marmara. The study participants were students whose results of the ORTO-15 questionnaire and EAT-40 attitude test indicated the presence of orthorexia. The evaluation of respondents' body composition indicators (bioelectric impedance on a Tanita SC-330 device) showed that there was no significant difference between the EAT-40 and ORTO-15 results in terms of body composition. The vast majority of respondents (70.6%) had high ORTO-15 results, and there was a significant negative correlation between EAT-40 and ORTO-15 results (p < 0.05). The final results of data analysis showed that although abnormal orthorexia tendencies were common among female students, they were able to maintain correct body composition. Similarly, a study by Haddad [23] showed that health sciences students, especially nutrition and dietetics students, showed a higher incidence of eating disorders. The study involved 176 undergraduate students from the Faculty of Nutrition and Dietetics. The study monitored food consumption and evaluated the frequency of eating owing to emotion and stress (EADES). Among the students participating in this study, 4.5% showed food dependency, and 68.2% showed orthorexia. No differences were observed between men and women in terms of food dependence and orthorexia. Students with orthorexia had increased BMI. Orthorexic students consumed more low-energy products, including vegetables, and less high-energy products (meat and fats). Multiple linear regression analysis showed that orthorexic behavior was associated with increased BMI, waist circumference, and energy intake. Lower BMI was associated with the ability to cope with EADES. In this study, similar results of the TFEQ-13 test were obtained. Malmborg et al. [24] conducted a study to compare the state of health, physical activity, and incidence of orthorexia among physical education and management students. Respondents completed a short quality of life assessment questionnaire (SF-36), International Physical Activity Questionnaire (IPAQ), and ORTO-15 questionnaire. Out of 188 students, 144 (76.6%) had an ORTO-15 score that indicated orthorexia, 84.5% of which were physical education students. Orthorexia combined with the high level of physical activity was more frequently observed in men studying physical education than in women studying physical education (45.1% vs. 8.3%). This confirms the hypothesis in our study that people who intensively practice sport may have significantly higher exposure to orthorexia than those with lower levels of physical activity. Similarly, a study by Grammatikopoulou et al. [24] showed that health sciences students, especially nutrition and dietetics students, showed a higher incidence of eating disorders. The study involved 176 undergraduate students from the Faculty of Nutrition and Dietetics in Greece. The study monitored food consumption and evaluated the frequency of eating owing to emotion and stress (EADES). Among the students participating in this study, 4.5% showed food dependency, and 68.2% showed orthorexia. No differences were observed between men and women in terms of food dependence and orthorexia. Students with orthorexia had increased BMI. Orthorexic students consumed more low-energy products, including vegetables, and less high-energy products (meat and fats). Multiple linear regression analysis showed that orthorexic behavior was associated with increased BMI, waist circumference, and energy intake. Lower BMI was associated with the ability to cope with EADES. In this study, similar results of the TFEQ-13 test were obtained.
The results obtained in the studies discussed above are consistent with the results obtained in the own study. In the conducted study, it was observed that 59-65% of the respondents showed orthorexic behaviors that were associated with excessive attention to their body shape. The discrepancies in the obtained results result from the use of two scales: the traditional ORTO-15 and the Polish ORTO-15 PL scale, which has been revised and its reliability has been confirmed for use in Polish conditions.
To sum up the above, it should be stressed that orthorexia is a disorder that occurs in human populations with different intensities. Many scientific studies discuss whether it should be included in the ICD and DSM list [25-26].