For much of history, humans lived near the equator and were exposed to higher amounts of ultraviolet light, resulting in higher levels of vitamin D in their bodies, said Thomas Wang, lead author of the cardiovascular risk and vitamin D study, which was published online Monday in the journal Circulation. "The levels we see today in developed countries are relatively unusual, especially from an evolutionary standpoint" said Wang, an assistant professor of medicine at Harvard Medical School. Full Article at RedOrbit