Does Light at Night Increase Breast Cancer?

A recent 10-year Israeli study of 1670 women suggests that those who routinely are exposed to more light during nighttime sleep had 22% higher odds of developing breast cancer than those who slept in full darkness. Fortunately, this can easily be controlled by light-blocking window shades or blinds in the bedroom. More research is needed, since precise measurements of light levels was not done.

PositiveTip: Sleeping in a dark room is part of good sleep hygiene, regardless of the potential connection with breast cancer.