Once again study suggests high vitamin D cuts breast cancer risk

A new study published in the Oct 2009 issue of Cancer Epidemiology Biomarkers Prevention suggests that high levels of vitamin D in the blood may help prevent breast cancer.

Numerous studies have linked vitamin D deficiency to elevated risk of breast cancer. Laboratory studies found evidence that vitamin D plays a role in breast cell physiology.

The current case-control study showed that women who had the highest tertile of 25-hydroxyvitamin D or 25OHD were at 48 percent reduced risk of breast cancer compared to those in the lowest tertile.

The study led by Rejnmark L and colleagues from Aarhus University Hospital in Denmark was meant to determine whether risk of breast cancer is associated with prediagnostic serum 25-hydroxyvitamin D levels and the effects of lifestyle characteristics known to affect vitamin D status on the risk of the disease.

For the study, the researchers analyzed data from 142 women with breast cancer and 420 women without the disease matched to cases on age, menopausal status, and time of year of blood sampling prior to the diagnostic mammography examination.

Women with breast cancer has lower levels of vitamin D than those without the disease, Rejnmark and colleagues found.

In addition to observing that women with highest levels of vitamin D were 48 percent less likely to have breast cancer, the researchers found the similar risk pattern in women with an estrogen receptor-positive and estrogen receptor negative breast cancer.

Use of vitamin D supplements, sunbathing, and fish consumption was found to be associated with 25OHD levels, but did not appear to affect the risk of the malignancy. However, it is unknown whether the lifestyle parameters were quantified and for this reason, the finding could not exclude their possible protective effect against the disease.

The researchers concluded that "risk of breast cancer was inversely associated with 25OHD levels. Randomized controlled trials are warranted in order to assess whether a causal relationship exists."

Dr. John Cannell, a vitamin D expert and president of Vitamin D Council suggests that to have a preventative effect, people should expose themselves to sunshine often and those who do not should take 4,000 to 5,000 IU of vitamin D daily.

For further information on vitamin D, read Dr. Cannell's website.

By David Liu davidl at foodconsumer dot org

Source:

Cancer Epidemiol Biomarkers Prev. 2009 Oct;18(10):2655-60. Epub 2009 Sep 29.

Reduced prediagnostic 25-hydroxyvitamin D levels in women with breast cancer: a nested case-control study.

Rejnmark L, Tietze A, Vestergaard P, Buhl L, Lehbrink M, Heickendorff L, Mosekilde L.

Department of Endocrinology and Metabolism C, Aarhus Sygehus, Aarhus University Hospital, Tage-Hansens Gade 2, DK-8000 Aarhus C, Denmark. rejnmark@post6.tele.dk

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