ABSTRACT
BackgroundVitamin D plays a vital part in modulating the immune system, with Vitamin D deficiency leading to increased susceptibility to infection.1 There is some evidence to suggest Vitamin D may play a protective role in the prevention of COVID-19 infection in hospitalised patients,2 but the topic remains controversial. Our study aims to investigate if low Vitamin D levels correlate with increased risk of COVID-19 infection, thereby representing a modifiable risk factor for COVID-19 infection.MethodA retrospective observational study was conducted on 3198 health care workers of a Greater London District General Hospital, who had undergone testing for 25-OH Vitamin D levels and COVID-19 antibody in June 2020. In accordance with NICE guidelines, Vitamin D deficiency was defined as less than 25 nmol/L, insufficiency as 25–50 nmol/L, and those with levels over 50 nmol/L were used as control comparisons. Evidence of previous SARS-CoV-2 infection was assessed by detection of SARS-CoV-2 IgG antibodies. Regression analysis was performed to determine independent significance, accounting for age and gender.Results3191 participants were included in this study, with age ranging from 19–78 years (mean 42.9) of which 78.2% were female. Both age and gender were not independently associated with positive SARS-CoV-2 IgG antibodies. 1997 (62.6%) participants had Vitamin D levels within the normal range, 899 (28.2%) participants had insufficient levels and 302 (9.4%) had Vitamin D deficiency. Both Vitamin D deficiency (OR 1.61, p=0.002) and insufficiency (OR 1.33, p=0.006) independently correlated with significantly increased incidence of positive COVID-19 antibodies than personnel with normal Vitamin D levels.ConclusionsWe report the largest single-centre study investigating the impact of low Vitamin D levels within healthcare workers to date. Significant correlation between low levels of Vitamin D and previous COVID-19 infection was identified. Oral Vitamin D supplementation to maintain levels >50 nmol/L may play a protective role against COVID-19. Larger studies are needed to investigate the role of Vitamin D supplementation in healthcare workers for further COVID-19 waves.ReferencesAranow C, et al. Journal of Investigative Medicine 2011;59:881–886.Nogues X, et al. J Clin Endocrinol Metab. 2021 Jun 7:dgab405.