Hossain, EMandal, SKSarkar, SJha, AMondal, R2025-08-132025-08-132025-06Hossain E, Mandal SK, Sarkar S, Jha A, Mondal R. A Study on Serum Vitamin D3 Level in Patients with Covid-19: A Cross-Sectional Study in Kolkata. National Journal of Medical Research . 2025 Jun; 15(2): 126-1312249-49952277-8810https://imsear.searo.who.int/handle/123456789/252789Background: Coronavirus disease (COVID-19) is a global pandemic caused by SARS-CoV-2. Vitamin D has immunomodulatory and anti-inflammatory properties, potentially influencing the disease course. This study assessed the prevalence of 25(OH) vitamin D deficiency in COVID-19 patients and its association with disease severity in the Indian population. Methodology: A hospital-based cross-sectional study was conducted at Medical College, Kolkata, including 100 RT-PCR-confirmed moderate and severe COVID-19 patients. Disease severity was categorized based on oxygen saturation. Serum 25-Hydroxy vitamin D levels were measured on admission, along with other hematological and biochemical parameters. High-resolution CT scans were performed to assess pulmonary involvement. Results: Vitamin D insufficiency and deficiency were observed in 18% and 67% of patients, respectively. Deficiency was more prevalent in severe cases (82.97%) than moderate cases (52.83%). The mean vitamin D levels in moderate and severe disease groups were 23.23±8.74 and 17.17±8.09 ng/ml, respectively. A significant association was found between vitamin D deficiency and COVID-19 severity (P = 0.006). The vitamin D cutoff for predicting severe disease was 18.57 ng/dl. Conclusion: Vitamin D deficiency is strongly associated with severe COVID-19 in the Indian population. Low vitamin D levels may predict disease severity, suggesting supplementation as a potential preventive strategy.Coronavirus diseaseCOVID-19Vitamin D25 Hydroxy Vitamin DDeficiencyJournal ArticleIndiaDepartment of Cardiology, Institute of Post Graduate Medical Education and Research, Kolkata, IndiaDepartment of General Medicine, Medical College, Kolkata, IndiaDepartment of Cardiology, Institute of Post Graduate Medical Education and Research, Kolkata, IndiaDepartment of General Medicine, Medical College, Kolkata, IndiaDepartment of General Medicine, Medical College, Kolkata, India