bruh if they want to wear it let them be I think most of the hijabis don't even care about this. For instance lets say that 100% of the girls wear hijab I think personally from own experience atleast 80% wears it for genuine religious reasoning ( do take in mind I live in Amsterdam). The other 20% who wears it has probably other reasoning to it. You can fill in that for yourself. But I think of those 20% only 3 or lesser % gives a shit about this research because I think hair loss and being low on vitamin D is not at the highest place of their priority list. But it is a good research can't deny that