Breast cancer patients with lower levels of vitamin D have a higher chance of having their cancer spread and are also more likely to die according to a study done by Canadian researchers. Researchers reported to the American Society of Clinical Oncology that more than three-quarters of women with breast cancer had a vitamin D deficiency, with only 24% reporting adequate levels when they were diagnosed. Women who were deficient were 94% more likely to have their cancer spread and 73% more likely to die than women with adequate levels. Speaking with Reuters, Dr. Richard Schilsky of the University of Chicago said, “"The women with the lowest vitamin D levels had the highest risk of death from breast cancer."