Bone mineral density testing is done to diagnose osteoporosis and help assess the risk of fractures. The study is the first to investigate the relationships among bone mineral density, traditional breast cancer risk assessment tool results, and breast cancer incidence among the same group of postmenopausal women.
To investigate these relationships, Dr. Zhao Chen of the University of Arizona Mel and Enid Zuckerman College of Public Health and her colleagues studied approximately 10,000 post-menopausal women taking part in the Women's Health Initiative, a study conducted in 40 clinical centres throughout the United States.
The researchers assessed the women's initial bone mineral density level as well as their score on the Gail risk model, a well known and commonly used tool that estimates five year and lifetime risk of invasive breast cancer for women 35 years of age or older. They then followed the women for an average of approximately eight years, noting which women developed breast cancer.
As expected, the study found that women with a high Gail score had a 35 percent increased risk of developing breast cancer compared to women with a lower Gail score. But the study also found a 25 percent increase in the risk of developing the disease with each unit increase in total hip bone mineral density t-score. While the two scores were independent of each other, women who had the highest scores on both assessments had a much higher risk in breast cancer.
Additional studies are needed to determine if the results from this investigation are applicable to a broader group of women, including minorities. The findings do not change the use of bone mineral density testing to diagnose osteoporosis or the need to treat osteoporosis in order to reduce the risk of fractures.
MEDICA.de; Source: American Cancer Society