Blood vitamin D levels are very strongly linked to bone density

There is an amazingly accurate correlation between vitamin D levels and bone density. Given my previous post about how "messy" correlations are in human studies, these results are dramatically and miraculously correlated. So basically put your bone density depends on your vitamin D levels which depend upon how much you expose your torso and legs to the sun.

This study took thousands of participants and measured their vitamin D blood levels and bone densities. Each person created a data point on the graph below. The top line is for European light skinned people, middle line for Latino skinned people which have a medium skin pigment with the lower line being black Americans.

Update: The paper changed units on me without noticing. My previous optimal vitamin D post stated that repletion zone was 30 - 100 ng/ml, where this graph the white zone is approximately 20 - 100 nmol/L. So they were close enough for me to be tricked! Since all other vitamin D posts are in ng/ml I will convert this graph into these units. This is done by dividing the numbers below by 2.5. This results in the white band starting at approximately 8 and ending at 40, with the end of the graph being 72 ng/ml.