Its been a while since I read this article by the Midwestern Doctor (Posted by Dr. Mercola). You might find some useful information in it.
Natural Light Is an Essential Nutient
I read somewhere that The Navy looked at sailors with Skin Cancer and found that those most affected were not those who were on a flight line or on the flight Desk where they received a lot of exposure, but the people who were bench techs and mechanics who were not exposed to sun. (This assumes no other issues with EMF or Chemical exposure.)
Bench techs and mechanics in the Navy were inside more, I bet, which relates to bigJ’s comment. Hmmm. Thank you!