The relationship between vitamin D status and inflammation, hospitalization, and mortality due to COVID-19

In a recent study published in PLUS ONEIn England, researchers explored associations between vitamin D levels and SARS-CoV-2 and severe acute respiratory syndrome infection, hospitalization, and mortality.

The study: Association between vitamin D status and COVID-19 in England: a cohort study using the UK Biobank. Image Credit: Irina Imago / Shutterstock


The coronavirus disease 2019 (COVID-19) vaccines have been effective; However, controlling the COVID-19 pandemic globally remains a challenge. Understanding the etiology of COVID-19 is essential to developing effective COVID-19 prevention strategies.

Vitamin D is vital for bone health. It regulates calcium and phosphate levels and has been reported in recent studies; However, the associations between vitamin D levels and SARS-CoV-2 infection and associated severity outcomes (hospitalization and mortality) are unclear.

about studying

In this study, researchers explored the potential protective effects of vitamin D against SARS-CoV-2 infection, hospitalization, and mortality in England.

Study participants were part of the United Kingdom (UK) Biobank and consisted of 40 to 69 years old residents of England, enrolled from 2006 to 2010. For the analysis, individuals who underwent multiple (>1) serum vitamin D tests and who underwent their health records e [primary care records, inpatient records, and death records (certificates)] Linked and followed up until 16 March 2020. Primary care data were obtained from Test Productivity Package (TPP) and Education Management Information Systems (EMIS) England, and inpatient care records and death certificates were obtained from National Health Service (NHS) England.

The initial study exposure was a serum 25-hydroxyvitamin D level measured at enrollment by chemiluminescence immunoassays and described as deficiency, deficiency, and sufficiency based on vitamin D levels as <25 nmol/L, 25 to 49 nmol/L, and 50 nmol/L, respectively. Individuals tested between April and October and between November and March were designated as 'during the summer months' and 'during non-summer months', respectively.

Secondary exposures consisted of prescribed or self-reported vitamin D supplementation, and relevant data were obtained via self-reported questionnaires. All medications listed in British National Formula Section 9.6.4, including vitamin D and related minerals such as calcium, fish oil and multivitamins, were considered vitamin D supplements.

The primary study outcome was either clinically diagnosed or PCR-confirmed – COVID-19, and secondary outcomes were hospitalization and deaths due to SARS-CoV-2 infection. The clinical diagnosis of COVID-19 was based on the codes SNOMED-CT (Systemic Nomenclature for Medicine – Clinical Terminology), CTV3 (Clinical Terminology Version 3) and ICD-10 (International Classification of Diseases, 10th revision). Hospitalizations and deaths associated with COVID-19 were recorded based on ICD-10 codes U071 and U072. Cox regression models with adjustments for demographic, comorbid, and stratified factors for the summer and non-summer months were used for analysis.


A total of 307,512 individuals were included in the analysis, most of whom were female and aged >70 years. During the summer months, some evidence is found of the relationship between vitamin D deficiency and the risk of being diagnosed with COVID-19 [hazard ratio (HR) 0.9]. Conversely, during the non-summer months, vitamin D deficiency was associated with an increased risk of SARS-CoV-2 infection compared to vitamin D deficiency (heart rate = 1.1). However, there was no evidence of associations between vitamin D deficiency or insufficiency and hospitalization associated with SARS-CoV-2 infection and mortality in the summer and non-summer months.

A total of 10,165 study participants were diagnosed with COVID-19 in the fall (51%), winter (31%) and spring (14%), while only a few cases were diagnosed in the summer (4%). Similar trends were observed in hospitalizations and deaths associated with COVID-19. After data adjustments, during or after the British summer months, there was no evidence of associations between vitamin D deficiency or deficiency and an increased risk of hospitalization associated with COVID-19 (in the British summer months: HR adjusted for deficiency and deficiency were 0.9 and 1.1, respectively, and during the non-summer months, the corresponding RHR was 1.1 and 0.9, respectively).

Similarly, no evidence of increased risk of mortality associated with SARS-CoV-2 infection was found among individuals with vitamin D deficiency or deficiency during or after the British summer months (during the British summer months: the HR adjusted for deficiency and deficiency was 0.8 and 1.1, respectively; during the non-summer months, the corresponding adjusted HRs were 1.4 and 1.5, respectively).

After adjusting for data, individuals with vitamin D deficiency had a 14% lower risk of being diagnosed with SARS-CoV-2 infection compared to those with adequate vitamin D during the British summer months (heart rate = 0.9). During the non-summer months, the risk of COVID-19 was 14% higher among vitamin D deficient individuals (heart rate = 1.1).

Some evidence showed that during the summer months, participants who took vitamin D supplements had an increased risk of COVID-19 (HR=1.2), hospitalization (HR=1.6), and mortality (HR=2.3) . During the British summer months, there was no evidence of a reduced risk of COVID-19 among individuals with self-reported vitamin D supplementation (HR=0.9), and COVID-19 risk was higher during the non-summer months (HR=0.9). 1.2).


Overall, study results showed inconsistent associations between serum vitamin D levels and COVID-19 diagnosis and no associations between vitamin D levels and hospitalization and COVID-19-related mortality. However, further research with recent vitamin D measurement data and systematic testing of SARS-CoV-2 is needed to investigate the potential role of vitamin D in preventing SARS-CoV-2 infection specifically.


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