Latitude, sunlight, and covid-19 by Marc Sorenson, EdD
Latitude, when compared to disease and disability, is an attention catcher. First of all, why would latitude be important? Is it because latitude itself creates disease? Is it because different latitudes lead to different temperatures? Could it be different distances from the magnetic poles are involved in human physiology? No, none of those answers is correct, yet, there is a simple answer to the link between latitude and disease. That answer is sunlight and vitamin D. Low latitudes (closer to the equator) receive much more sunlight, and sunlight is more direct much of the year.
A study of latitude backs the efficacy of sunlight, and possibly vitamin D, on reducing the risk of Covid-19. This was a large, study, drawing reliable data from 88 countries. The researchers compared the countries for Covid-19 death rates and then compared them for the latitude.
The results of Covid-19 death rates compared to latitude.
Highly significant, positive correlations were found between lower mortality rates from Covid-19 and a country’s proximity to the equator. The researchers stated that their evidence suggested a direct correlation between sun exposure and reduced mortality. They also assumed that vitamin D was the photoproduct of sunlight that lowered the risk of Covid-19.
This was a good, timely study in that it established sunlight as a prophylactic for covid-19. Many studies had previously mentioned vitamin D as the primary blood measure to reduce risk of the Covid-19, but none has mentioned latitude as a factor to furnish proof. In addition, neither does this study really furnish proof. That is because the only study that will prove the relationship would be a vitamin D-supplement study.
Other research,which links vitamin D levels to reduced Covid-19 mortality, but does not mention latitude as a factor.
Another recent study on the association of vitamin D levels to covid-19 survival shows promise for vitamin D. It states that fourteen observational studies show that high D levels inversely correlate with the incidence or severity of Covid-19. Yet, we should always remember that sun exposure on skin produces 90% of the vitamin D levels in most populations. Furthermore, 20 minutes of full-body summer sun exposure at midday produces up to 20,000 IU of vitamin D.
Finally, a word about sunbeds (tanning beds)
Finally, realize that sunbeds (tanning beds) produce vitamin D and enhance health. In addition, it is likely they would also reduce Covid-19. Sunbeds produce vast quantities of vitamin D. People in Canada who use sunbeds have the highest levels of vitamin D in the country, especially in winter. Moreover, a 20-year study demonstrated that both sun exposure and sunbed exposure reduced the risk of death. Women who used sunbeds were 23% less likely to die from any cause than women who did not use them. Another advantage is that latitude does not matter with sunbed use.
From the available research, it is evident that sunlight and vitamin D are protective against Covid-19. Sunlight exposure at midday, or sunbed use, are always the best sources, since sunlight exposure produces many health benefits beyond vitamin D.