Most Brazilians don't have high levels of vitamin D. Do you know that phrase coined in the British Raj, that only mad dogs and Englishmen go out in the midday sun? It turns out that to bask in the tropical heat isn't exactly comfortable to most people.
https://www.scielo.br/scielo.php?script=sci_arttext&pid=S0004-27302007000300012
https://www.scielo.br/scielo.php?script=sci_arttext&pid=S0004-27302008000300008
Regardless, older people will produce vitamin D more slowly than younger people, same as the difference between darker and lighter skin, so both ethnicity and age disparity would add to the confounding factors at play here.
Of course, since the immunomodulatory effects of vitamin D have been known for a long time, a little sunshine here and there can't hurt.
Essay Pro