Breast cancer medication may increase risk of developing type 2 diabetes

Women who take the drug tamoxifen after being diagnosed and treated for breast cancer may be at a slightly higher risk of developing type 2 diabetes, according to a new study.

The researchers stressed that their investigation did not prove the drug causes diabetes. The team simply noted an association between tamoxifen and the medical condition, which could have been caused by other confounding factors.

Still, after examining the medical records of more than 14,000 women being treated for breast cancer, the researchers found that considerably more participants being treated with tamoxifen eventually developed type 2 diabetes. Tamoxifen patients were at a 25 percent higher risk.

While the University of Toronto researchers who conducted the study said they do not believe tamoxifen was the sole cause of any diabetes cases, they do think the medication may exacerbate preexisting risk factors like obesity or a family history of metabolic conditions.

Regardless, they said more research should be conducted to determine the exact cause of the association. The study could have important implications, as tamoxifen is one of the most commonly prescribed medications for preventing a recurrence of breast cancer. Currently, more than 500,000 women take the drug, according to a study conducted by researchers from Oxford University.

Other aspects of breast cancer treatment may contribute to type 2 diabetes risk. It can be very difficult to maintain a healthy weight while undergoing chemotherapy, as the medication alters the way foods taste. Many people find it difficult to eat healthier foods that may be more acidic. Furthermore, chemotherapy causes fatigue, and many breast cancer patients become less physically active than they once were.

However, the researchers did take some of these factors into consideration, indicating tamoxifen may play a direct role in the development of type 2 diabetes among breast cancer patients.