WASHINGTON (AP) _ Older women with high bone density are about two times more likely to develop breast cancer, a study finds.
The study, appearing Wednesday in the Journal of the National Cancer Institute, followed the health history of 8,905 women who were 65 or older and free of breast cancer. After six years, the study found, those who scored highest on three types of bone mineral density tests were also more likely to develop breast cancer.
Women with high bone density were also more likely to be diagnosed with advanced breast cancer, the study found.
``The results suggest that bone mineral density is one of the most powerful predictors of breast cancer, especially advanced breast cancer, among elderly women,'' Dr. Jane Cauley, a researcher at the University of Pittsburgh Medical Center and a co-author of the study said in a statement.
Bone density, the researchers said, is not a cause of breast cancer, but it is an indirect measure of levels of hormone, such as testosterone and estrogen, that have been linked both to bone density and to breast cancer.
In the study, the researchers measured the bone density in the wrist, forearm and heel of the women. The women were then monitored for more than six years.
During that period, 315 of the 8,905 developed breast cancer. Analysis showed that women in the quarter of the group with the highest bone density in the forearm were about 2.8 times as likely to develop breast cancer as those who were in the lowest bone density quarter of the group. A similar relationship was found for the other bone density tests.