Vitamin D and COVID-19 infection and mortality in UK Biobank

The findings of this study do not support a potential link between vitamin D concentrations and risk of COVID-19 infection in the UK, nor that vitamin D concentration may explain ethnic differences in COVID-19 infection.

• Median 25(OH)D concentration measured at recruitment was lower in patients who subsequently had confirmed COVID-19 infection (43.8 nmol/L) than other participants (47.2 nmol/L).
• Vitamin D was associated with COVID-19 infection when only the two were compared but not after adjustment for confounders.
• Ethnicity (Black vs White and South Asian vs White) was associated with COVID-19 infection. Adjustment for 25(OH)D concentration made little difference to the magnitude of the association.

UK Biobank recruited 502,624 participants aged 37-73 years across England, Scotland and Wales between 2006 and 2010. Its aim was to identify the causes of disease and death in middle and old age by following  participants over time. At baseline, biological measurements were recorded and touch-screen questionnaires were administered according to a standardized protocol. Complete data collected between 2006-2010 on vitamin D (25(OH)D) concentration and social, health and economic characteristics (i.e., potential confounders) derived from the questionnaires were available for 348,598 UK Biobank participants. Of these, 449 had a positive COVID-19 test during the study period.

• This study relies on historical data collected between 2006-2010 on vitamin D (25(OH)D) concentration and self-reported social, health and economic characteristics that may have changed significantly by the advent of the COVID-19 pandemic in early 2020.
• The total number of subjects 449 is small and the population characteristics are representative of the UK and may not be consistent with global populations.
• Although the median 25(OH)D concentrations suggest mild insufficiency in this population, it does not suggest widespread deficiency. No current data regarding self-supplementation of vitamin D is provided.
• Note that incorrect values for age and vitamin D concentrations were transcribed from summary statistics, and variable categories were the wrong way around for smoking status, long-standing illness, disability or infirmity and diabetes in the original publication. This summary cites the corrected statistics for Table 1 and some text that can be found here:

Hastie, C. E., Mackay, D. F., Ho, F., Celis-Morales, C. A., Katikireddi, S. V., Niedzwiedz, C.            L., Jani, B. D., Welsh, P., Mair, F. S., Gray, S. R., O’Donnell, C. A., Gill, J. M., Sattar, N. and         Pell, J. P. (2020) ‘Corrigendum to “Vitamin D concentrations and COVID-19 infection in     UK Biobank” [Diabetes Metabol Syndr: Clin Res Rev 2020 14 (4) 561-5]’, Diabetes Metab     Syndr, 14(5), pp. 1315-1316.

This study found no link between serum 25(OH)D concentration and COVID-19 risk, suggesting that measurement of 25(OH)D would not be useful to assess risk of COVID-19 in clinical practice. Furthermore, the results suggest that vitamin D is unlikely to be the underlying mechanism for the higher risk observed in Black and minority ethnic individuals and vitamin D supplements are unlikely to provide an effective intervention.

• Of the 449 COVID-19 positive patients evaluated, 41% were female with a median age at initial assessment (2006-2010) of 43.8 years (range 28.7-61.6 years). In addition, 85.8% self-reported as White, 7.1% as Black, 4.% as South Asian and 2.9% as Other.
• Analysis was performed of the association between 25(OH)D concentration and confirmed COVID-19 infection. The model was then adjusted for potential confounders, including sex, month of assessment, economic deprivation quintile, household income, self-reported health rating, smoking status, BMI quintile, ethnicity, age at assessment, diabetes, systolic blood pressure, diastolic blood pressure and longstanding illness, disability or infirmity.
• These models were repeated with participants categorized as vitamin D deficient (defined as <25 nmol/L) or not deficient and then categorized as vitamin D insufficient (defined as<50 nmol/L) or sufficient.

Hastie CE, Pell JP, Sattar N. Vitamin D and COVID-19 infection and mortality in UK Biobank. Eur J Nutr. 2021 Feb;60(1):545-548. doi: 10.1007/s00394-020-02372-4. Epub 2020 Aug 26. PMID: 32851419; PMCID: PMC7449523.