Common osteoporosis drugs are associated with a decrease in risk of breast cancer

Women who take some types of bone-building drugs used to prevent and treat osteoporosis may be at lower risk of breast cancer, according to a study by US researchers published in the British Journal of Cancer.

The study found that women who used bisphosphonate drugs, such as Fosamax, Boniva and Zomita, for more than two years had a nearly 40% reduction in risk as compared to those who did not, according to lead author Polly Newcomb, head of the Cancer Prevention Program at Fred Hutchinson Cancer Research Center. "This large study provides new evidence that the use of bisphosphonates is associated with a potentially important reduction in breast cancer risk," Dr Newcomb said.

The protective effect was observed only among women who were not obese. "Obese women may have elevated estrogen levels, so underlying hormones may influence the ability of bisphosphonates to reduce breast cancer risk," Dr Newcomb noted.