Researchers from Toronto Canada have published the results of a study that included 512 women who were diagnosed with early breast cancer between the years of 1989 and 1995.  The study followed these women through 2006.  Once diagnosed with early breast cancer, these woman had their levels of vitamin D measured in their blood.

Researchers concluded:

• Less than 1/4 of the women diagnosed had adequate levels of vitamin D in their blood;
• Women with low levels of vitamin D had a 94% increased risk of cancer spread than those with adequate vitamin D levels; and
• Women with low levels of vitamin D had a 73% increased risk of death than those with adequate vitamin D levels.

Vitamin D is used by the body to maintain normal levels of calcium and phosphorous, aiding the absorption of calcium and helping the body form and maintain strong bones.  It is generally synthesized by the body through exposure to sunlight, and through a person's diet or supplements.

Exactly what the protective benefits of vitamin D holds with respect to cancers is not known.  In fact, some studies have shown that vitamin D contributes to the risk of developing some cancers, especially breast cancers.

Through their study, the Toronto researchers have concluded that the results adds to the growing evidence that show vitamin D levels not only play a potentially important role in the risk of developing breast cancer, but may also affect breast cancer outcomes. Further studies will help researchers better understand the association between vitamin D and breast cancer.

The results of the study were presented in the American Society of Clinical Oncology.