Detectable respiratory SARS-CoV-2 RNA is associated with low vitamin D levels and high social deprivation

Background: Accumulating evidence links COVID-19 incidence and outcomes with vitamin D status. We investigated if an interaction existed between vitamin D levels and social deprivation in those with and without COVID-19 infection.

Methods: Upper or lower respiratory tract samples from 104 patients were tested for SARS-CoV-2 RNA in accordance with Public Health England criteria (January-May 2020) using RT-PCR. The latest serum total 25-hydroxyvitamin D(25-OHD) levels, quantified by LC-MS/MS, was obtained for each patient (September 2019-April 2020). Index of Multiple Deprivation (IMD) was generated for each patient. Univariate and logistic regression analyses examined associations between age, gender, 25-OHD, IMD score and SARS-CoV-2 result in the total cohort and subgroups.

Results: In the total cohort, a positive SARS-CoV-2 test was significantly associated with lower 25-OHD levels and higher IMD. A positive test was associated with higher IMD in the male subgroup and with lower 25-OHD levels in those aged >72 years. Low 25-OHD and IMD quintile 5 were separately associated with positive COVID-19 outcome in the cohort. Patients in IMD quintile 5 with vitamin D levels ≤ 34.4 nmol/L were most likely to have a positive COVID-19 outcome, even more so if aged >72 years (OR: 19.07, 95%CI: 1.71-212.25; P = .016).

Conclusions: In this cohort, combined low vitamin D levels and higher social deprivation were most associated with COVID-19 infection. In older age, this combination was even more significant. Our data support the recommendations for normalising vitamin D levels in those with deficient / insufficient levels and in groups at high risk for deficiency.