After being diagnosed with osteoporosis, I have been told by my new physician that small children, the elderly and especially small boned, fair skinned women over 40 are at a dangerous risk of bone loss due to complete lack of sunshine, which is one of only two ways to obtain Vitamin D - Calciferol.
Yes, here in Holland we have a lot of cases of orthodox muslim women getting shortage of vitamin D. This because they are often kept inside the house, and the rare times that they are allowed out of the house they wear burka's. Apparently they can live with this in arab countries as there is so much sun that even a little bit can give you enough (or maybe muslim women adapted to surviving on less sunlight) but in holland there is so little sun, that they are now getting insufficient amounts.