Examining Associations Among Orthorexia Nervosa and Anthropometric Factors and Lifestyle Habits in an Italian University Community

Background/Objectives: Orthorexia nervosa (ON) is characterized by an obsession with rigid dietary rules, which leads to an emphasis being placed on food purity and health. Exploring the prevalence rates and understanding the potential risk factors associated with ON is essential for developing effective prevention and intervention strategies. This study investigated the prevalence of ON and examined different variables in associations to enhance our knowledge of their impact on ON tendency. Methods: A sample of 500 participants, including 357 women and 143 men, aged between 20 and 60, from an Italian university community was recruited to complete an online survey assessing ON, using the 15-item self-report measure ORTO-15, and Mediterranean diet adherence and lifestyle habits using the Mediterranean Diet Adherence Screener (MEDAS) and the Mediterranean Lifestyle Index (MEDLIFE) questionnaires, respectively. Student’s t-test, ANOVA, chi-squared test, and multiple linear regressions were used for analyses. Results: We found that MEDAS and MEDLIFE scores were statistically higher in males than in females, while the ORTO-15 score was significantly lower in females than in males. In the total, ON prevalence was 19.8% (women = 16.08% and men = 21.28%). Multiple regression analyses on the ORTO-15 score and different variables showed that in our population sample, ON was associated with female sex (β = −2.98; p = 4 × 10⁻⁶) and the body mass index (BMI) (β = −0.41; p = 6.71 × 10⁻⁷). When adjusting for sex and the BMI, the resulting ORTO-15 score was associated with health science faculty attendance (β = 1.26, p = 0.003), following a food plan (β = −3.14; p = 1 × 10⁻⁷) and carrying out physical activity (β = −1.20; p = 0.03). Conclusions: This study identified the importance of several factors for ON focusing on lifestyle habits that clinicians should consider when assessing patients at risk for eating disorders. Further studies are warranted to better define the diagnostic criteria of ON and develop effective prevention and intervention strategies to promote a healthy relationship with food.