Covid’s vitamin D link: What data from 20 countries show

Vitamin D is known to modulate the response of white blood cells, preventing them from releasing too many inflammatory cytokines (part of the body’s immune response to fight infections).

A new study has found an association between low average levels of vitamin D and high numbers of Covid-19 cases and mortality rates across 20 European countries. The research, led by scientists from UK’s Anglia Ruskin University (ARU) and Queen Elizabeth Hospital King’s Lynn NHS Foundation Trust, is published in the journal Aging Clinical and Experimental Research.

Vitamin D is known to modulate the response of white blood cells, preventing them from releasing too many inflammatory cytokines (part of the body’s immune response to fight infections). And the SARS-CoV2 virus is known to cause an excess of pro-inflammatory cytokines, called a cytokine storm.

The new study shows that Italy and Spain, both of which have experienced high Covid-19 mortality rates, have lower average vitamin D levels than most northern European countries. This, the researchers said, is partly because people in southern Europe, particularly the elderly, avoid strong sun, while skin pigmentation also reduces natural vitamin D synthesis.

The highest average levels of vitamin D are found in northern Europe, due to the consumption of cod liver oil and vitamin D supplements, and possibly less sun avoidance. Scandinavian nations are among the countries with the lowest number of COVID-19 cases and mortality rates per head of population in Europe, ARU said in a statement on the new research.

“We found a significant crude relationship between average vitamin D levels and the number Covid-19 cases, and particularly Covid-19 mortality rates, per head of population across the 20 European countries,” Dr Lee Smith of ARU said in the statement.

“Vitamin D has been shown to protect against acute respiratory infections, and older adults, the group most deficient in vitamin D, are also the ones most seriously affected by Covid-19. A previous study found that 75% of people in institutions, such as hospitals and care homes, were severely deficient in vitamin D. We suggest it would be advisable to perform dedicated studies looking at vitamin D levels in COVID-19 patients with different degrees of disease severity,” Dr Lee said. —Source: Anglia Ruskin University