I live in southern Brazil (one of these tropical countries), where sunlight is not that easy to get; also people dress up and cover themselves much more than in other regions due to not only the weather but also for cultural reasons. In fact, the city where I live (Curitiba) has a huge portion of people who need vitamin D supplements, to the point this deficiency became folkloric. I was quite "happy" to learn last year that after a full decade here my blood exam showed for the first time in 35 years that now I need vitamin D supplements too.