Written by Joyce Smith, BS. This study found an association between low average levels of vitamin D and high numbers of COVID-19 cases and mortality rates across 20 European countries.
Studies have already validated vitamin D’s safety and its ability to protect against acute respiratory infections 1; however, its potential role in COVID-19 is controversial. Previous studies have found associations between higher levels of angiotensin converting enzyme 2 (ACE2), and better health outcomes to those with coronavirus disease. ACE2 is the receptor for both the SARS-CoV-2 and the related human respiratory coronavirus NL63 that allows the virus to attach to cells and replicate, yet in the human lung, ACE2 has been shown to protect against injury. 2
The objective of this study 3 was to identify a potential association between mean levels of vitamin D in twenty European countries and the number of cases of COVID-19 and the deaths it has caused. After determining mean vitamin D levels for each country, Ilie and colleagues compared the mean vitamin D levels with the observed number of COVID-19 cases and COVID-19 deaths per million population. Their data analysis revealed significant negative correlations in various European countries between mean vitamin D levels and both the number of COVID-19 cases (P=0.05) and mortality caused by COVID-19 infection (P=0.05) per one million population. The team found that the most vulnerable group for COVID-19 was the aging European population that was most deficient in Vitamin D levels. They suggest that this association may be the result of vitamin D’s potential role in the prevention of COVID-19 infection or it may potentially protect against the more negative consequences of the infection.
Southern European countries such as Italy and Spain have all experienced high COVID-19 mortality rates. In particular, both Italy and Spain have lower average vitamin D levels than most northern European countries. A possible explanation may be that southern Europeans tend to avoid strong sun 4 or perhaps their greater skin pigmentation may contribute to less natural vitamin D synthesis 5. The highest average levels of vitamin D are found in northern Europe, where cod liver oil, vitamin D fortified milk and milk products, and vitamin D supplements are regularly consumed, and possibly more exposure to sunlight occurs 5. In fact, Scandinavian nations are among the European countries with the lowest number of COVID-19 cases and mortality rates per one million population.
The European Calcified Tissue Society Working Group has described severe vitamin D deficiency as a serum 25(OH) D level lower than 30 nmol/L 6. Older people in Spain have a current mean serum vitamin D level of 26 nmol/L, in Italy the mean serum Vitamin D level is 28 nmol/L and in the Nordic countries it is 45 nmol/L 6. Switzerland’s nursing home residents have a mean vitamin D level of 23 nmol/L, while in Italy, 76% of women over 70 years of age have been shown to have circulating levels of vitamin D below 30 nmol/L 6. A study of Italian women 70 years of age and older found that in late winter months 76% of them were severely vitamin D deficient, with circulating levels of25(OH)D that were less than 12 ng/mL (30 nmol/L 7.
Among the limitations of this cross-sectional analysis is the fact that many variables affected the number of reported COVID-19 cases in each country, including the number of tests performed in each country and the different preventive measures taken by each country to control the spread of COVID-19. The study authors conclude that the highest number of COVID-19 cases occur in European countries where aging populations have the greatest deficiency in Vitamin D levels and are at the highest risk for morbidity and mortality with COVID-19. Future studies to determine the vitamin D levels in COVID-19 patients with different degrees of disease severity are recommended.
Source: Ilie, Petre Cristian, Simina Stefanescu, and Lee Smith. “The role of vitamin D in the prevention of coronavirus disease 2019 infection and mortality.” Aging Clinical and Experimental Research (2020): 1.
© Springer Nature Switzerland AG 2020
Posted June 4, 2020.
Joyce Smith, BS, is a degreed laboratory technologist. She received her bachelor of arts with a major in Chemistry and a minor in Biology from the University of Saskatchewan and her internship through the University of Saskatchewan College of Medicine and the Royal University Hospital in Saskatoon, Saskatchewan. She currently resides in Bloomingdale, IL.
References:
- Cannell JJ, Vieth R, Umhau JC, et al. Epidemic influenza and vitamin D. Epidemiology and infection. 2006;134(6):1129-1140.
- Kuba K, Imai Y, Penninger JM. Angiotensin-converting enzyme 2 in lung diseases. Curr Opin Pharmacol. 2006;6(3):271-276.
- Ilie PC, Stefanescu S, Smith L. The role of vitamin D in the prevention of coronavirus disease 2019 infection and mortality. Aging Clin Exp Res. 2020:1-4.
- Adami S, Bertoldo F, Braga V, et al. 25-hydroxy vitamin D levels in healthy premenopausal women: association with bone turnover markers and bone mineral density. Bone. 2009;45(3):423-426.
- Matsuoka LY, Wortsman J, Haddad JG, Kolm P, Hollis BW. Racial pigmentation and the cutaneous synthesis of vitamin D. Arch Dermatol. 1991;127(4):536-538.
- Lips P, Cashman K, Lamberg-Allardt C et al (2019) Current vitamin D status in European and Middle East countries and strategies to prevent vitamin D deficiency: a position statement of the European Calcified Tissue Society. Eur J Endocrinol 180:23–54
- Isaia G, Giorgino R, Rini GB et al (2003) Prevalence of hypovitaminosis D in elderly women in Italy: clinical consequences and risk factors. Osteoporos Int 14:577–582
