High Vitamin D Levels Linked to Better Long-Term Outcomes in Breast Cancer Patients

A new study from Kaiser Permanente and Roswell Park Cancer Institute revealed that high levels of vitamin D in the blood of patients diagnosed with breast cancer had significantly better long-term outcomes.

The study, published in the journal JAMA Oncology, suggests that the better breast cancer outcomes of women with higher levels of vitamin D is related to the role of the vitamin in promoting normal mammary-cell production. Additionally, the researchers also noted that vitamin D may inhibit the production of and promote the death of cancer cells.

"With the extremely rich data sources from a large sample size, we were able to prospectively analyze three major breast cancer outcomes -- recurrence, second primary cancer and death," explained Song Yao, PhD, associate professor of oncology at Roswell Park Cancer Institute and lead author of the study, in a press release.

For the study, the researchers analyzed the data of 1,666 participants of the Kaiser Permanente's Pathways study that was first conducted in 2006.Each participant of the study was diagnosed with invasive breast cancer in 2006. The researchers asked the participants for blood samples within two months of diagnosis. Additionally, the participants answered questions about their diet, lifestyle and other risk factors. Follow-ups were conducted at six months and at two, four, six and eight years.

The researchers found that participants with the highest levels of vitamin D in the study had about 30 percent better likelihood of survival than woman with the lowest levels of vitamin D. After adjusting for multiple possible contributing factors that could influence vitamin D levels, the researchers found even stronger associations among premenopausal women in the highest third of vitamin D levels for breast-cancer-specific (63 percent better), recurrence-free (48 percent better) and invasive-disease-free survival (42 percent better), during a median follow up of seven years.

Vitamin D is a nutrient best known for its role in maintaining healthy bones. The most common sources of vitamin D include sun exposure, fatty fish oil, vitamin supplements, and fortified milk and cereals.