Strong correlation between prevalence of severe vitamin D deficiency and population mortality rate from COVID-19 in Europe

Background: Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) causes a very wide range of disease severity: from completely asymptomatic to fatal, and the reasons for that are not well understood; however, there are some data that show vitamin D may have a protective effect.

Methods: To retrieve the vitamin D levels data, the authors analyzed the vitamin D European population data compiled by 2019 European Calcified Tissue Society (ECTS) statement on vitamin D status published in the European Journal of Endocrinology. For the data set to be used for analysis, only recently published data that included general adult population of both genders aged 40-65 years or wider and must have included the prevalence of vitamin D deficiency.

Results: There were data sets from 10 countries that fitted the criteria and were analyzed. Severe vitamin D deficiency was defined as 25(OH)D less than 25 nmol/L (10 ng/dL). Pearson correlation analysis between death rate per million of population from coronavirus disease 2019 (COVID-19) and prevalence of severe vitamin D deficiency showed a strong correlation with r = 0.79, p = 0.007. Over time, correlation strengthened, and r coefficient asymptotically increased. After adjusting for countries' age structure and per capita health expenditures, multiple linear regression analysis showed that higher prevalence of severe vitamin D deficiency is associated with increased mortality. Each 1% increase in prevalence increased deaths by 55 per million (95% confidence interval, CI 8-102), p = 0.03.

Conclusion: The authors recommend universal screening for vitamin D deficiency, and further investigation of Vitamin D supplementation in randomized control studies, which may lead to possible treatment or prevention of COVID-19.