Dietary Supplementation Practices Among Undergraduate Students in Greece During the COVID-19 Pandemic and Their Association with COVID-19-related Anxiety.

Background: Despite the lack of evidence-based guidance on supplement use for the prevention and treatment of COVID-19, consumption of dietary supplements has been shown to increase in many countries. Objective: This study aimed to explore the use of dietary supplements among undergraduate students. Methods: An online cross-sectional survey was conducted between May and June 2021, involving a total of 536 participants (57.8% female) aged between 18-30 years in two university towns in central and northern Greece. Two validated questionnaires were used regarding dietary supplements and stress during COVID-19. Results: The prevalence of dietary supplement use was 67.5%. The three most popular supplements consumed were vitamin C (65.2%), followed by vitamin D (58.3%), and multivitamin and mineral supplements (56.9%). The use of CAS-5 indicated that 13.1% of students were classified as having dysfunctional anxiety due to COVID-19 (CAS-5 score ≥5). Logistic regression analysis showed that those who exhibited CAS-5 ≥5 were over two times more likely to consume supplements compared to no-stress participants (OR 2.29, 95%CI: 1.09-4.82). Particularly vitamin D use was associated with CAS score ≥5 (OR 2.18, 95%CI 1.22-3.89) a finding that was not observed with other types of dietary supplements. Conclusion: Women, passive smokers, and those who believe that DS are necessary during the COVID-19 pandemic were also more likely to consume dietary supplements. The use of dietary supplements is widespread among Greek students. Future studies should be conducted to monitor whether these increases in DS use are maintained.