Abstract: Article Possible Impact of Vitamin D Status and Supplementation on SARS-CoV-2 Infection Risk and COVID-19 Symptoms in a Cohort of Patients with Inflammatory Bowel Disease Amedeo De Nicolò 1,*,†, Jessica Cusato 1,†, Cristina Bezzio 2, Simone Saibeni 2, Marta Vernero 3, Michela Disabato 3, Gian Paolo Caviglia 3, Alice Ianniello 1, Alessandra Manca 1, Antonio D’Avolio 1,‡ and Davide Giuseppe Ribaldone 3,‡ Laboratory of Clinical Pharmacology and Pharmacogenetics, Department of Medical Sciences, University of Turin, 10149 Turin, Italy 2 Gastroenterology Unit, Rho Hospital, ASST Rhodense, 20017 Milan, Italy 3 Gastroenterology Unit, Department of Medical Sciences, University of Turin, 10126 Turin, Italy * Correspondence: amedeo.denicolo@unito.it; Tel.: +39-0114393867 † These authors contributed equally to this work. ‡ These authors also contributed equally to this work. 1 Citation: De Nicolò, A.; Cusato, J.; Bezzio, C.; Saibeni, S.; Vernero, M.; Disabato, M.; Caviglia, G.P.; Ianniello, A.; Manca, A.; D’Avolio, A.; et al. Possible Impact of Vitamin D Status and Supplementation on SARS-CoV-2 Infection Risk and COVID-19 Symptoms in a Cohort of Patients with Inflammatory Bowel Disease. Nutrients 2023, 15, 169. https:// Abstract: The coronavirus disease (COVID-19) pandemic represents a global health challenge, particularly considering concomitant diseases. Patients with inflammatory bowel diseases (IBD) can be considered a population at risk. On the other hand, the risk of developing IBD and COVID-19 have both been described as modulated by vitamin D (VD) levels. In this work, a cohort of 106 adult patients affected by IBD was prospectively enrolled, during the second wave of the pandemic in Italy. In these patients, VD plasma levels, demographic, and clinical characteristics were tested for a correlation/an association with the risk of infection with SARS-CoV-2 in the study period (antispike IgG positivity) and the severity of COVID-19 symptoms. By multivariate logistic regression analysis, VD supplementation (Odds Ratio; OR 0.116, p = 0.002), therapy with monoclonal antibodies (OR 0.227, p = 0.007), and the use of mesalazine (OR 2.968, p = 0.046) were found to be independent predictors of SARS-CoV-2 positivity. Moreover, hypertension was associated with severe disease (p = 0.019), while a VD level higher than 30 ng/mL (p = 0.031, OR 0.078) was associated with asymptomatic infection. No interplay between IBD activity and COVID-19 risk of infection or symptoms was observed. These results confirm the importance of VD levels in defining the risk of COVID-19 and give encouraging data about the safety of maintaining immunomodulatory treatments for IBD during the COVID-19 pandemic. Keywords: vitamin D; cholecalciferol; IBD; Crohn’s disease; ulcerative colitis; monoclonal antibodies; SARS-CoV-2; COVID-19 doi.org/10.3390/nu15010169 Academic Editor: Hongbing Sun Received: 7 November 2022