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dcyphr | Vitamin D concentrations and COVID-19 infection in UK Biobank

Abstract 

Minority ethnic and black individuals appear to be disproportionately affected by low vitamin D levels and COVID-19 infection. This study aims to establish if blood levels of vitamin D are associated with COVID-19 infection risk. UK biobank recruited 502,624 participants aged 37-73 years. Exposure data and blood vitamin D levels were acquired. The data was then cross referenced. Complete data was available for 348,598 UK Biobank participants. Only 449 participants had confirmed COVID-19 infection. Once all variables were accounted for the data did not show any association between blood vitamin D levels or the effect of ethnicity on infection risk. The results do not support a link between blood vitamin D concentrations and risk of COVID-19 infection. The results also fail to observe ethnic differences in infection risk as a result of blood vitamin D levels. 


Introduction 

    COVID-19 has led to a pandemic of pneumonia-related illness. The researchers predict the case fatality to be 1%. According to the Intensive Care National Audit and Research Centre roughly one third of all reported cases are non-white. There is growing evidence that COVID-19 disproportionately affects minority ethnic and black individuals. The US has seen similar patterns of infection. Therefore, it is critical that we understand the relationship between COVID-19 and ethnic minorities. Several factors could lead to this trend. UK government statistics show that black or minority ethnic individuals tend to live in more socioeconomically deprived areas of England. Similarly, these groups tend to experience higher levels of underlying medical issues. 

    One potential reason for this could be that ethnic minorities and black individuals tend to have lower levels of vitamin D. Vitamin D is produced in the skin and is a result of exposure to UV radiation. However, the melanin in darker skin will absorb less UV radiation. This results in less vitamin D production. This study hypothesized that blood vitamin D concentrations were associated with COVID-19 risk among UK Biobank participants. 


Materials and Methods 

Biological baselines were taken and touch screen questionnaires were given to every participant. Ethnicity was self reported as white, black, South Asian, or other. Various factors such as socioeconomic status (SES), smoking habits, and general health were all self reported. All variables were accounted for to make sure a valid baseline could be achieved before comparison. This essentially means that various factors such as health, race, BMI,  and SES were taken into account when analyzing the data. This prevented distortion of the results.


Results 

The median blood vitamin D concentration was lower in patients who had confirmed infection than those without infection. However, after adjusting for various other factors such as SES, health, BMI, and race there was no relation between vitamin D concentration and COVID-19 infection. There was no statistically significant interaction between vitamin D and ethnicity. Median blood concentrations of vitamin D were highest in white individuals and lowest in South Asian participants There is higher risk found for males and individuals who BMI classifies them as obese. 

   

Discussion 

     This study was consistent with others in showing a higher infection risk to black and ethnic minority groups. No association was found between blood vitamin D concentration and COVID-19 infection as adjusting for variables. Blood vitamin D concentrations were lower in black and minority ethnic individuals. Despite this, there is no evidence it causes a higher risk to COVID-19 infection. Further studies are required to determine potential biological mechanisms that may vary between ethnic and black individuals. The difference in infection risk could be social factors or cardiometabolic conditions. 

    This study failed to find an association between blood pressure and infection risk. Similarly, there was no observed risk for smokers. However, the literature on the effects of smoking is still mixed at this current time. This study was large, but not representative of the general population. This study finds no link between blood vitamin D concentration and COVID-19 infection risk. Similarly, the results of this study suggest that vitamin D supplements are unlikely to provide assistance in prevention. 


Conclusion

The results of this study do not provide evidence to support a role regarding blood vitamin D concentration on COVID-19 infection. Nor, does blood vitamin D concentration explain differences between ethnic groups.