Scientists have found an association between low average levels of vitamin D, and high numbers of COVID19 cases and mortality rates across 20 European countries, and call for dedicated studies to probe into the relationship.
Based on earlier studies, the researchers, including Lee Smith of Anglia Ruskin University in the UK, said there is an association between low levels of vitamin D and susceptibility to acute respiratory tract infections.
In the current research, they said vitamin D modulates the response of white blood cells, preventing them from releasing too many inflammatory molecules called cytokines which are produced in excess in patients with severe COVID19.
Italy and Spain have both experienced high COVID-19 mortality rates, and according to the new study, both countries have lower average vitamin D levels than most northern European countries.
They said this 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, the researchers said.
They said Scandinavian nations are among the countries with the lowest number of COVID19 cases and mortality rates per head of population in Europe. “We found a significant crude relationship between average vitamin D levels and the number COVID19 cases, and particularly COVID19 mortality rates, per head of population across the 20 European countries,” Lee Smith, study co-author from Anglia Ruskin University, said.