PLoS ONE (Jan 2022)

Vitamin D and SARS-CoV2 infection, severity and mortality: A systematic review and meta-analysis.

  • Oriana D'Ecclesiis,
  • Costanza Gavioli,
  • Chiara Martinoli,
  • Sara Raimondi,
  • Susanna Chiocca,
  • Claudia Miccolo,
  • Paolo Bossi,
  • Diego Cortinovis,
  • Ferdinando Chiaradonna,
  • Roberta Palorini,
  • Federica Faciotti,
  • Federica Bellerba,
  • Stefania Canova,
  • Costantino Jemos,
  • Emanuela Omodeo Salé,
  • Aurora Gaeta,
  • Barbara Zerbato,
  • Patrizia Gnagnarella,
  • Sara Gandini

DOI
https://doi.org/10.1371/journal.pone.0268396
Journal volume & issue
Vol. 17, no. 7
p. e0268396

Abstract

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To assess the evidence on SARS-CoV2 infection and Covid-19 in relation to deficiency and supplementation of vitamin D, we conducted a systematic review up to April 2021. We summarised data from 38 eligible studies, which presented risk estimates for at least one endpoint, including two RCT and 27 cohort-studies: 205565 patients with information on 25OHD status and 2022 taking vitamin D supplementation with a total of 1197 admitted to the ICU or who needed invasive mechanical ventilation or intubation and hospital stay, and more than 910 Covid-19 deaths. Primary outcomes were severity and mortality and the main aim was to evaluate the association with vitamin D supplementation. Random effects models showed that supplementation was associated with a significant lower risk of both Covid-19 severe disease (SRR 0.38, 95% CI 0.20-0.72, 6 studies) and mortality (SRR 0.35, 95% CI 0.17-0.70, 8 studies). There were no statistically significant dose differences between studies: summary estimates with regular doses remain statistically significant, suggesting that higher doses are not necessary. For patients on vitamin D supplementation, a greater reduction in mortality risk emerged in older individuals and at higher latitudes. Regarding the quality of studies, assessed using the New Castle-Ottawa quality scale, the analysis revealed in most cases no statistically significant differences between low, medium or high quality studies. We found significant associations of vitamin D supplementation with Covid-19, encompassing risks of disease worsening and mortality, especially in seasons characterized by 25OHD deficiency and with not severe patients. Dedicated randomized clinical studies are encouraged to confirm these results.