I have told ALa/ABMOM to switch to a daytime shift (she's currently 7pm -7am in the ICU) because of the elevated rates for cancer in night-shift nurses. It seems that it's the artificial lights suppressing melatonin that causes the problem --so I would assume this is true of any night-shift occupation.
"The risk of developing breast cancer is about five times higher in industrialized nations than it is in underdeveloped countries. These results suggest that the increasing nighttime use of electric lighting, both at home and in the workplace, may be a significant factor."
In a press release, NIEHS noted that previous research has found that artificial light suppresses the production of melatonin, a hormone that helps regulate a person's sleeping and waking cycles.
The federal institute says this new study "shows that melatonin also plays a key role in [preventing] the development of cancerous tumors." (source)
The one thing about the linked study that doesn't make sense to me is that fact that most night-workers sleep all day, so doesn't the amount of light they encounter even out?
When it comes to artificial light, I think I am in the clear. The Man and I HATE lights. If you come to the House of Sage prepare for low light vision --and remember that parka....