New study shows that even in sunny Africa Vitamine-D deficiency is quite common, comparable to Europe. That is because where the sun shines heavy, people tend to avoid it. Or they must work all day in enclosed halls and rooms.
https://www.thelancet.com/journals/l...457-7/fulltext
Myself, I had just suffered my first attack by polymorphic light dermatosis this year, or in brief: sun allergy. I am vulnerable to it since last year, when I first was struck by it. I cannot expose my unprotected skin to sunlight anymore, must wear hats, sunblocker, UV-protecting long sleaves shirt loosely over my T-shirt, and thicker trousers than until last year. It sucks, but I cannot help it, sunlight causes me very severe skin rash and absolutely awful itching for 3-5 days of terrible itching and 12-14 days of skin dots. So, even in sunny summer I am certain I am highly vitamine-D deficient. In hotter countries, the natives oftehnj poratcice sun-.evading loiving styles and habits. So, a sunny country does not automatically means less Vitmaine-D deficiency of the population. People in Mexico and India are known to be very deficient, for example.