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Study Finds Vitamin D Gene Variation May Increase Risk of Breast Cancer (dateline October 22, 2001)


Some experts have suggested that vitamin D may provide a protective effect against breast cancer, and in certain cases, help treat the disease. While further studies are needed to better understand what role vitamin D plays in association with breast cancer, new research finds that women who have genetic variations that prevent their bodies from making use of vitamin D may be at greater risk of developing breast cancer than women without these genetic abnormalities. If further research confirms these findings, scientists may be able to pinpoint dietary changes that could help reduce the risk of breast cancer in these women.

The study was conducted by Dr. Kay Colston and her colleagues from St. George’s Hospital Medical School in London, England. The researchers compared 241 healthy women between the ages of 50 and 81 to 181 breast cancer patients between the ages of 29 and 91. Dr. Colston and her team found that the breast cancer patients were twice as likely to have a certain genetic variation of a vitamin D receptor (called BsmI), which makes them less likely to benefit from vitamin D. The breast cancer patients with genetic variations of the vitamin D receptor were also more likely to have aggressive breast cancer tumors compared with the breast cancer patients that did not have these genetic variations.

According to the researchers, this study adds to previous evidence that problems with vitamin D receptors may affect the development of breast cancer. However, they also caution that this area of research needs to be further investigated in large studies. To this end, Dr. Colston and her colleagues plan to recruit 1600 women, half with breast cancer and half without the disease, to continue their research.

In the future, Dr. Colston says that the assessment of genetic variations of vitamin D receptors may be important in determining which women may be at high risk of developing breast cancer. Once these women are identified, they may be candidates for aggressive preventive measures, such as the drug tamoxifen (brand name, Nolvadex) or close monitoring by physicians. Dietary changes may also be identified to help these women reduce their risk of breast cancer. According to The Cancer Research Campaign, some breast cancer treatments are being developed based on vitamin D.

Yet, Dr. Colston and her colleagues emphasize that their study findings do not suggest that women should take large quantities of vitamin D to help prevent breast cancer. In fact, women with a genetic variation of the vitamin D receptor may or may not respond to vitamin D supplements. Before beginning to take vitamin or dietary supplements, women should discuss them with their physicians to make sure they are safe and effective.

Even if further research determines that abnormalities of vitamin D receptors play a role in breast cancer, this would only be one risk factor for the disease. Researchers have previously identified several other factors that may increase the risk of breast cancer. These factors include:

For most women, the best method of defense against breast cancer is to detect the disease in its earliest stages when it can most easily be treated. To help accomplish this, all women 40 years of age and older should have yearly screening mammograms, practice monthly breast self-exams, and receive yearly clinical breast exams. Women younger than age 40 should also practice monthly breast self-exams and receive regular clinical breast exams. Women younger than age 40 who are at high risk of breast cancer (such as those with a strong family history of the disease) should talk to their physicians about beginning breast cancer screening at an earlier age.

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