World Health Organization announced the novel coronavirus disease outbreak to be a global pandemic. The distribution of community outbreaks shows seasonal patterns along certain latitude, temperature, and humidity i.e. similar to the behavior of seasonal viral respiratory tract infections. COVID-19 displays significant spread in northern midlatitude countries with an average temperature of 5-11 °C and low humidity. Vitamin D deficiency has also been described as pandemic, especially in the Europe. Regardless of age, ethnicity, and latitude; recent data showed that 40% of the Europeans are vitamin D deficient (25(OH)D levels <50 nmol/L), and 13% are severely deficient (25(OH)D <30 nmol/L).A quadratic relationship was found between the prevalences of vitamin D deficiency in most commonly affected countries by COVID-19 and the latitudes. Vitamin D deficiency is more common in the subtropical and midlatitude countries than the tropical and high latitude countries. The most commonly affected countries with severe vitamin D deficiency are from the subtropical (Saudi Arabia; 46%, Qatar; 46%, Iran; 33.4%, Chile; 26.4%) and midlatitude (France; 27.3%, Portugal; 21.2% and Austria; 19.3%) regions. Severe vitamin D deficiency was found to be nearly 0% in some high latitude countries (e.g. Norway, Finland, Sweden, Denmark and Netherlands).Accordingly, we would like to call attention to the possible association between severe vitamin D deficiency and mortality pertaining to COVID-19. Given its rare side effects and relatively wide safety, prophylactic vitamin D supplementation and/or food fortification might reasonably serve as a very convenient adjuvant therapy for these two worldwide public health problems alike. Accepted manuscript supplementation for potential risk of hypercalcemia while taking high doses of vitamin D3. Needless to say; as vitamin D is synthesized mainly in the skin, sun (UV-B) exposure (15-20 min daily) inducing the light pink color of minimal erythema would be the natural way of production and activation of vitamin D by keratinocytes. 55 Accordingly, presenting this paper, we would like to call attention to the possible association between severe vitamin D deficiency and mortality pertaining to COVID-19. Given its rare side effects and relatively wide safety, prophylactic vitamin D supplementation and/or food fortification might reasonably serve as a very convenient and incomparable/invaluable adjuvant therapy for these two worldwide public health problems alike. al. Low serum vitamin D is not associated with an increase in mortality in oldest old subjects: the Octabaix three-year follow-up study. Gerontology. 2014; 60: 10-5. 13. Veronese N, Sergi G, De Rui M, et al. Serum 25-hydroxyvitamin D and incidence of diabetes in elderly people: the PRO.V.A. study. J Clin Endocrinol Metab. 2014; 99: 2351-8. 14. Aspell N, Laird E, Healy M, et al. The prevalence and determinants of vitamin D status in community-dwelling older adults: Results from the English Longitudinal Study of Ageing (ELSA). Nutrients. 2019; 11...
