Vitamin D deficiency is associated with an increased risk of hospitalization due to COVID-19: a backward-looking case-control study.

PMID: 34139758 DOI: 10.1210 / clinem / dgab439

Commentary

Because vitamin D deficiency is a hypothesized risk factor for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection, this study was a backward-looking case-control study of the disease course of COVID-19 in northwest England (NWE).

The study included individuals with serum 25-hydroxyvitamin D (25 [OH] D) results between April 1, 2020, and January 29, 2021, and patients were recruited from two districts of the NWE.

Patients were recruited from two districts in the NWE. The last 25 [OH]D level in the previous 12 months was classified as "insufficient" if it was less than 25 nmol/L and "inadequate" if it was between 25 and 50 nmol/L.

As a result, 80,670 participants were included, 1,808 were hospitalized with COVID-19, and 670 of them died.

According to the primary cohort, the median serum 25(OH)D in participants not hospitalized with COVID-19 was 50.0 [interquartile range, IQR 34.0-66.7] nmol/L, compared with 35.0 [IQR 21.0-57.0] nmol/L in participants who were hospitalized. 

There were similar findings in the validation cohort (median serum 25(OH)D 47.1 [IQR 31.8-64.7] nmol/L in non-hospitalized patients vs. 33.0 [IQR 19.4-54.1] nmol/L in hospitalized patients), and the odds ratios adjusted for age, sex, and seasonal variation of hospitalization were 50 The risk of death was 2.3 to 2.4 times higher in participants with serum 25(OH)D less than 50 nmol/L compared to participants with normal serum 25(OH)D levels.

These conclude that vitamin D deficiency is associated with a higher risk of COVID-19 hospitalization, and that extensive measurement of serum 25(OH)D and treatment of unmasked dysfunction or deficiency by testing may reduce this risk.