ABSTRACT
Background: Some vitamins play a beneficial role in the immune system and certain diseases may be associated with an increase in the number of COVID-19 cases and mortality. Objective(s): In this work, we aim to verify a possible relationship between vitamin A, vitamin D, sunlight, and COVID-19 cases and mortality. We also aim to study the relationship between chronic diseases and COVID-19 in the world. Method(s): We consulted online databases (Johns Hopkins, World Life Expectancy, NASA, and World Health Organization) and used SPSS (v23) for statistical analysis. Result(s): We found that countries with the highest number of cases and deaths by COVID-19 are the countries with the highest death rates from different types of cancer and multiple sclerosis. Besides, the relationship between cancer death rate and COVID-19 is not biased by the life expectancy. We also found that the low solar incidence and low vitamins A and D levels can be related to the number of cases and deaths by COVID-19. Conclusion(s): Our findings suggest a relationship between different cancer types and multiple sclerosis death rates and COVID-19. We also recommend that vitamins D and A may play a protective role in COVID-19 infection.Copyright © 2021 Bentham Science Publishers.