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.
Objectives: 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.
Methods: We consulted online databases (Johns Hopkins, World Life Expectancy, NASA, and World
Health Organization) and used SPSS (v23) for statistical analysis.
Results: 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: 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