Vitamin D Levels Low Even in Breast Cancer Patients Taking Supplements

Zosia Chustecka

December 10, 2010

December 10, 2010 (San Antonio, Texas) — Vitamin D levels are low even in postmenopausal women with breast cancer who are taking supplements, a new study has found.

The research was featured in a poster presentation here at the 33rd Annual San Antonio Breast Cancer Symposium. It was based on a cross-sectional study of 391 postmenopausal women with stage I to III breast cancer who were taking aromatase inhibitors. Vitamin D deficiency was found in 35% of these women.

A majority of the women (73%) were taking vitamin D supplements, but even among this group, vitamin D deficiency was found in 25%.

The main message from this work is that vitamin D supplementation is not "one size fits all," said lead author Claire Friedman, BS, from the New York University School of Medicine in New York City. There are some women who might benefit from extra doses, such as women who are obese and overweight or who are nonwhite, she told Medscape Medical News.

The finding that so many of these postmenopausal breast cancer survivors were found to be vitamin D deficient is of concern, because previous research has shown that vitamin D deficiency is associated with worse breast cancer outcome, she explained.

Ms Friedman is a fourth-year medical student, and was working under the guidance of senior author Jun Mao, MD, MSCE, from the University of Pennsylvania in Philadelphia. The patients were being treated at the Rena Rowan Breast Cancer Center at the University of Pennsylvania, she noted.

Vitamin D levels were measured in a blood sample taken from each patient, and deficiency was defined as a level below 30 ng/mL.

The median level of vitamin D was 35 ng/mL (range, 6.78 to 93.15).

However, 35% of women had levels of vitamin D that indicated deficiency. After adjustment for age and vitamin D supplementation, the researchers found that vitamin D deficiency was more likely to be found in minorities than in whites (adjusted odds ratio, 2.18; P = .009), and in women who were obese or overweight than in those of normal weight (adjusted odds ratio, 3.21; P < .001).

"Hypovitaminosis D is common in breast cancer survivors, and women who are nonwhite or overweight are at higher risk of deficiency, despite taking vitamin D supplements," the researchers conclude.

33rd Annual San Antonio Breast Cancer Symposium (SABCS). Abstract P2-14-11. Presented December 10, 2010.


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