Abstract: Annals of Medicine and Surgery 68 (2021) 102661 Contents lists available at ScienceDirect Annals of Medicine and Surgery journal homepage: www.elsevier.com/locate/amsu Case-controlled Study Vitamin D deficiency and COVID-19: A case-control study at a tertiary care hospital in India Nirav Nimavat a, Shruti Singh b, *, Pratibha Singh c, Sunil Kumar Singh b, Nishi Sinha b a Department of Community Medicine, SBKS MIRC, Sumandeep Vidyapeeth Deemed to be University, Vadodara, Gujarat, India Department of Pharmacology, AIIMS, Patna, Bihar, India c Department of Anaesthesiology, Sanjay Gandhi Postgraduate Institute of Medical Sciences, Lucknow, India b A R T I C L E I N F O A B S T R A C T Keywords: Vitamin D COVID-19 Case-control Clinical severity Background: As the pandemic COVID-19 affected developing and developed countries, there is no proven treatment options available yet. The anti-inflammatory, antiviral and immune modulator effect of Vitamin D could be beneficial to COVID-19. Aim: To find out the possible association between Vitamin D and COVID-19. Methods: The present case-control study was conducted at tertiary care hospital, AIIMS, Patna, Bihar, India. Total 156 cases and 204 controls were enrolled in the study after obtaining informed consent. Categorization of the patients were done based on clinical severity and level of Vitamin D. The association between these categories with different variables were analyzed using regression analysis and other statistical tests. Results: The status of Vitamin D (optimal, mild to moderate deficiency and severe deficiency) differed signifi­ cantly among cases and controls. Diabetes and hypertension were most prevalent comorbidities among cases. On regression analysis, the difference in Vitamin D level was significant (aOR, 3.295; 95%CI, 1.25–8.685). The association between Vitamin D status and clinical severity group was statistically significant among cases. Among all variables, age, diabetes, hypertension and clinical severity were associated with worst outcome. Conclusion: Vitamin D status appears to be strongly associated with COVID-19 clinical severity. After COVID-19 confirmation, Vitamin D level should be measured in all patients and curative plus preventive therapy should be initiated.