Tehran University of Medical Sciences The Research in Heart Yield and Translational Medicine (RHYTHM) 3115-7270 21 1 2026 04 26 12 19 Arya Aminorroaya Section of Cardiovascular Medicine, Department of Internal Medicine, Yale School of Medicine, New Haven, CT Ali Vasheghani Farahanni Tehran heart center Hamed Tavolinejad Tehran Heart Center, Cardiovascular Diseases Research Institute, Tehran University of Medical Sciences, Tehran, Iran Zahra Aryan Department of Medicine, Rutgers New Jersey Medical School, Newark, NJ, USA Somayeh Yadangi Tehran heart center Ali Bozorgi Tehran heart center Saeed Sadeghian Tehran heart center Mohammadali Boroumand Tehran heart center Masud Yunesian School of Public Health, Tehran University of Medical Sciences, Tehran, Iran Masih Tajdini Division of Cardiology, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA 2025 11 07 2025 12 09 Background: Clinical evidence suggests an association between vitamin B12 deficiency and vasovagal syncope (VVS) in pediatric patients. This study investigated the association of vitamin B12 and folate deficiency with VVS in adults. Methods: In this case-control study, adult patients with VVS who presented to the tertiary syncope unit for head-up tilt table testing comprised the case group. Age- and sex-matched individuals without syncope history from the population-based Tehran Cohort Study served as the control group. Exclusion criteria included but were not limited to the use of vitamin B supplements, carbamazepine, or phenobarbital, and sleeve gastrectomy. Serum vitamin B12, folate, and homocysteine levels were measured and compared. Results: From February 2020 through February 2021, 44 patients comprised the case group, matched with 44 controls (mean age, 37.9 years; 23 [52.3%] females in each group). No statistically significant difference existed between the groups in vitamin B12 or folate deficiency or serum levels. Serum vitamin B12 levels were significantly lower in patients with frequent VVS (≥3 lifetime episodes) than in patients with infrequent VVS (<3 lifetime episodes) (233.8 [80.7] vs 305.2 [118.1] pg/mL; P=0.042), and the association remained significant after adjustment for confounders (P=0.026). Conclusion: No association existed between vitamin B12 or folate deficiency or serum levels and VVS. Frequent VVS was associated with lower serum vitamin B12 levels than infrequent VVS. https://jthc.tums.ac.ir/index.php/jthc/article/view/2390 https://jthc.tums.ac.ir/index.php/jthc/article/download/2390/1241