I don't know; vitamin D supplements may be mostly advised in places where there just isn't enough sun. In Scotland we get insufficient sunshine to produce natu

I don't know; vitamin D supplements may be mostly advised in places where there just isn't enough sun. In Scotland we get insufficient sunshine to produce natural vitamin D for around 6 months of the year, and there's discussion about whether everyone should be supplementing to the point it's been mooted as an addition to the water supply. That's relevant because nobody uses sun screen during those months. I wouldn't expect any kind of correlation through sheer lack of use.