In 1998, anthropologist Nina Jablonski and her husband George Chaplin collected spectrometer data to measure UV radiation levels around the world and compared it to published information on the skin color of indigenous populations of more 50 countries. The results showed a very high correlation between UV radiation and skin color; the weaker the sunlight was in a geographic region, the lighter the indigenous people’s skin was. Jablonski went on to prove that people living above the latitudes of 50 degrees have the highest chance of developing vitamin D deficiency.