Vitamin may cut cancer deaths
Researchers look at deficiency in D
WASHINGTON - Breast cancer patients with lower levels of vitamin D were far more likely to die and far more likely to have their cancer spread than women with normal levels, Canadian researchers reported yesterday.
Women deficient in the "sunshine vitamin" when they were diagnosed with breast cancer were 94 percent more likely to have their cancer spread and were 73 percent more likely to die than women with adequate vitamin D levels, the researchers said.
More than three-quarters of women with breast cancer had a vitamin D deficiency, the researchers reported for an upcoming meeting of the American Society of Clinical Oncology.
"The women with the lowest vitamin D levels had the highest risk of death from breast cancer," Dr. Richard Schilsky of the University of Chicago and president-elect of the society said in an interview.
"We are seeing an association. It is possible that vitamin D is simply a marker for a healthy lifestyle. We don't think that is the case," said Dr. Pamela Goodwin of Mount Sinai Hospital in Toronto, who led the study.
The study adds to a growing evidence that vitamin D, made when sunlight hits the skin and used to fortify many foods, including milk, is important for preventing chronic diseases. It is key to maintaining strong bones.
Goodwin's team studied 512 women with a mean age of 50 with newly diagnosed breast cancer treated at three University of Toronto hospitals between 1989 and 1995. They were followed until 2006, a median of just under 12 years.
Twenty-four percent of the patients had adequate levels of vitamin D when they were diagnosed with cancer.
Goodwin said optimal levels are considered to be between 80 and 110 or 120 nanomoles per liter of blood, although there are no standard guidelines. They considered anything less than 50 nanomoles per liter to be deficient.
After 10 years, the cancer did not spread or come back in 83 percent of the women with normal levels, and 85 percent of these women were still alive. But 69 percent of the women with low vitamin D levels were cancer-free 10 years later, and 74 percent were alive.
Women with low vitamin D levels were also likely to have developed cancer before reaching menopause and had higher body mass indexes, a measure of being overweight; higher insulin levels; and more aggressive tumors.
