Association Between Vitamin D Deficiency and COVID-19 Incidence, Complications, and Mortality in 46 Countries: An Ecological Study

Each patient´s immune defenses play a major role in mitigating the impact (ie, morbidity and mortality) of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the virus responsible for coronavirus disease 2019 (COVID-19). Vitamin D is an important modulator of the immune system. Although serum 25-hydroxyvitamin D levels can be raised through diet or supplements, most vitamin D in the body is the result of dermal synthesis from ultraviolet radiation. The production of vitamin D in the skin, however, can be limited by latitude, skin-covering clothes, the use of sunblock, and skin pigmentation. Vitamin D deficiency affects a high percentage of the world population. Serum 25-hydroxyvitamin D levels are suboptimal, not only in specific risk groups but also in adults from many countries. Low vitamin D levels, therefore, represent a risk factor for several different pathologies, including SAR-CoV-2. This study used an ecological design to assess the association between vitamin D deficiency and COVID-19 incidence, complications, and mortality across 46 countries. All data were obtained from published sources. The results of the study suggest an association at the population level between the prevalence of vitamin D deficiency and the risk of being infected with COVID-19, severity of the disease, and risk of dying from it. Fil: Mariani, Javier. Provincia de Buenos Aires. Ministerio de Salud. Hospital Alta Complejidad en Red El Cruce Dr. Néstor Carlos Kirchner Samic; Argentina Fil: Martín Giménez, Virna Margarita. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - San Juan; Argentina. Universidad Catolica de Cuyo. Facultad de Ciencias Quimicas y Tecnologicas; Argentina Fil: Bergam, Ivana. Croatia Osiguranje Pension Company; Croacia Fil: Tajer, Carlos Daniel. Provincia de Buenos Aires. Ministerio de Salud. Hospital Alta Complejidad en Red El Cruce Dr. Néstor Carlos Kirchner Samic; Argentina Fil: Antonietti, Laura. Provincia de Buenos Aires. Ministerio de Salud. Hospital Alta Complejidad en Red El Cruce Dr. Néstor Carlos Kirchner Samic; Argentina Fil: Inserra, Filipe. Universidad Maimónides; Argentina Fil: Ferder, León. Universidad Maimónides; Argentina Fil: Manucha, Walter Ariel Fernando. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mendoza. Instituto de Medicina y Biología Experimental de Cuyo; Argentina