Vitamin D status: a U-shaped relationship for SARS-CoV-2 seropositivity in UK healthcare workers

Sebastian T Lugg, William R Mackay, Aduragbemi A Faniyi, Sian E Faustini, Craig Webster, Joanne E Duffy, Martin Hewison, Adrian M Shields, Dhruv Parekh, Alex G Richter, Aaron Scott, David R Thickett*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

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Background There is increasing evidence that vitamin D (VD) deficiency may increase individuals' risk of COVID-19 infection and susceptibility. We aimed to determine the relationship between VD deficiency and sufficiency and COVID-19 seropositivity within healthcare workers. Methods The study included an observational cohort of healthcare workers who isolated due to COVID-19 symptoms from 12 May to 22 May 2020, from the University Hospitals Birmingham National Health Service Foundation Trust. Data collected included SARS-CoV-2 seroconversion status, serum 25(OH)D 3 levels, age, body mass index (BMI), sex, ethnicity, job role and comorbidities. Participants were grouped into four VD categories: (1) Severe VD deficiency (VD<30 nmol/L); (2) VD deficiency (30 nmol/L ≤VD<50 nmol/L); (3) VD insufficiency (50 nmol/L ≤VD<75 nmol/L); (4) VD sufficiency (VD≥75 nmol/L). Results When VD levels were compared against COVID-19 seropositivity rate, a U-shaped curve was identified. This trend repeated when participants were split into subgroups of age, sex, ethnicity, BMI and comorbidity status. Significant difference was identified in the COVID-19 seropositivity rate between VD groups in the total population and between groups of men and women; black, Asian and minority ethnic (BAME) group; BMI<30 (kg/m 2); 0 and +1 comorbidities; the majority of which were differences when the severely VD deficient category were compared with the other groups. A larger proportion of those within the BAME group (vs white ethnicity) were severely VD deficient (p<0.00001). A larger proportion of the 0 comorbidity subgroup were VD deficient in comparison to the 1+ comorbidity subgroup (p=0.046). Conclusions Our study has shown a U-shaped relationship for COVID-19 seropositivity in UK healthcare workers. Further investigation is required to determine whether high VD levels can have a detrimental effect on susceptibility to COVID-19 infection. Future randomised clinical trials of VD supplementation could potentially identify 'optimal' VD levels, allowing for targeted therapeutic treatment for those at risk.

Original languageEnglish
Article numbere001258
Number of pages10
JournalBMJ Open Respiratory Research
Issue number1
Early online date27 Sept 2022
Publication statusPublished - 27 Sept 2022

Bibliographical note

Funding Information:
Research support was provided by the National Institute for Health Research (NIHR)/Wellcome Trust Birmingham Clinical Research Facility. Laboratory work was done at the Clinical Immunology Service of the University of Birmingham and the Biochemistry department within the University Hospitals Birmingham NHS Foundation Trust.

Publisher Copyright:
© Author(s) (or their employer(s)) 2022. Re-use permitted under CC BY-NC. No commercial re-use. See rights and permissions. Published by BMJ.


  • COVID-19
  • respiratory infection
  • viral infection

ASJC Scopus subject areas

  • Pulmonary and Respiratory Medicine


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