Vitamin D in the news: A call for clear public health messaging during Covid-19.

Background: The public are increasingly reliant on the internet and media to access healthcare related information during the Covid-19 pandemic. Vitamin D is essential for musculoskeletal and immune health, with daily supplementation advised by public health bodies. Several studies assessing a possible link between vitamin D and Covid-19 severity have arrived at conflicting results and news articles have been rapidly disseminating such research to the public. There has been little focus on studying the quality of information available. Aim: To identify if online search interest in vitamin D increased with pandemic burden and analyse the accuracy of public health messaging relating to vitamin D in online news articles. Methods: Online search interest data for vitamin D was correlated with pandemic burden, defined as the number of Covid-19 deaths. Online news articles discussing vitamin D and Covid-19 were analysed using qualitative coding. Results: Online search interest for vitamin D increased as pandemic burden increased (p < 0.0001, Spearman's rank). Of the 72 articles identified, most (50%) offered a mixed opinion on the benefit of vitamin D in Covid-19. From articles making a recommendation for vitamin D supplementation, 23% of articles gave mixed messaging or advised against supplementation. 16% of articles recommended a dose which exceeded the safe limit of 4000 IU/day, risking toxicity. Conclusion: A significant number of articles provided mixed messaging or incorrectly advised supratherapeutic doses. This study highlights an opportunity for public health bodies to utilise the increased interest in vitamin D during the pandemic to raise awareness with accurate information.

Dexamethasone treatment may mitigate adverse effects of vitamin D deficiency in hospitalized Covid-19 patients.

AIMS: We have previously demonstrated that vitamin D deficiency might be associated with worse outcomes in hospitalized Covid-19 patients. The aim of our study was to explore this relationship with dexamethasone therapy. METHODS: We prospectively studied two cohorts of hospitalized Covid-19 patients between March and April and between September and December 2020 (n = 192). Patients were tested for serum 25-hydroxyvitamin D (25-OH-D) levels during admission. The first cohort not treated with dexamethasone (n = 107) was divided into vitamin D deficient (25-OH-D ≤ 30 nmol/L) (n = 47) and replete subgroups (25-OH-D > 30 nmol/L) (n = 60). The second cohort treated with dexamethasone (n = 85) was similarly divided into deficient (25-OH-D ≤ 30 nmol/L) (n = 27) and replete subgroups (25-OH-D > 30 nmol/L) (n = 58). Primary outcome was in-hospital mortality and secondary outcomes were elevation in markers of cytokine storm and ventilatory requirement. RESULTS: No mortality difference was identified between cohorts and subgroups. The "no dexamethasone" cohort 25-OH-D deplete subgroup recorded significantly higher peak D-Dimer levels (1874 vs. 1233 µgFEU/L) (p = 0.0309), CRP (177 vs. 107.5) (p = 0.0055), and ventilatory support requirement (25.5% vs. 6.67%) (p = 0.007) compared to the replete subgroup. Among the 25-OH-D deplete subgroup higher peak neutrophil counts, peak CRP, peak LDH, peak ferritin, and lower trough lymphocyte counts were observed, without statistical significance. In the "dexamethasone" cohort, there was no apparent association between 25-OH-D deficiency and markers of cytokine storm or ventilatory requirement. CONCLUSION: Vitamin D deficiency is associated with elevated markers of cytokine storm and higher ventilatory requirements in hospitalized Covid-19 patients. Dexamethasone treatment appears to mitigate adverse effects of vitamin D deficiency.