MedPageToday -- Sleeping with the lights on could increase the risk of breast cancer, results from a large 10-year observational study suggest. The case control study of more than 1,670 Israeli women, found that those routinely exposed to higher intensity light in their sleeping environment had 22% higher odds of developing breast cancer than women who slept in full darkness (P<0.001), according to Abraham Haim, PhD, of the University of Haifa, and colleagues.
