Lower vitamin-D, higher breast cancer risk

Photo credits: Jacek Chabraszewski

No woman ever wants to hear the words “You have breast cancer,” but what if the same woman was told “Breast cancer may develop soon.” instead? Would she be as heart broken? Researchers of the University of California, San Diego (Yea, I spelled out UCSD..waddup?), SDSU, and Heartland Assays (Iowa) discovered that low detectable levels of vitamin D are closely linked with risk of developing breast cancer in young women.

The group found that women who had low serum 25-hydroxyvitamin-D (25(OH)D) three months prior to diagnosis had lower levels of vitamin-D that correlated with their risk of breast cancer. Varied levels prior to this three month period showed no significant link to risk of breast cancer.

25(OH)D is the broken down form of Vitamin D3 that physicians measure for in the blood when detecting vitamin-D concentration.

Vitamin D deficiency has an increasing prevalence in the U.S. as sunscreens with high levels of protection become more popular. Everyday use of such protection blocks UVB, which is needed to make vitamin-D in the body. For this reason, the risk of developing vitamin-D deficiency is higher in late summer/early fall/winter. However, that tangent was just a small aside.

Vitamin-D deficiency has been linked to other types of cancer such as prostate. For this reason, the current study was executed to ascertain the possible link between serum 25(OH)D levels and breast cancer risk.

600 women with breast cancer were matched to 600 control women without breast cancer for this case-control retrospective study. In analysis of 25(OH)D levels of all women, those in the lowest quintile (Q1) of concentration had a three times greater risk of developing breast cancer (Odds ratio: 3.3) than those in the highest quintile (Q5) (Odds ratio: 1.0, p trend = 0.09). However, this association was only seen when levels were low at most 90 days prior to diagnosis.

Because low concentrations showed no significant link greater than 90 days prior to diagnosis, perhaps the tumor is sequestering vitamin-D rapidly during its initial growth. The mechanism of interaction between vitamin D and breast cancer is currently unknown, but further research may reveal a causal relationship between the two. Vitamin-D may be a link to breast cancer prevention, further studies will tell.

For now, this study shows that low pre-diagnostic levels of vitamin-D are significantly associated with higher risk of breast cancer. Abnormal drops in vitamin-D levels may be usable in early detection of breast cancer.

Sharif B. Mohr, Edward D. Gorham, John E. Alcaraz, Christopher I. Kane, Caroline A. Macera, J. Kellogg Parsons, Deborah L. Wingard, Ronald Horst, Cedric F. Garland. Serum 25-hydroxyvitamin D and breast cancer in the military: a case–control study utilizing pre-diagnostic serum. Cancer Causes and Control, 2013.