Hip bone density may help determine breast cancer risk

Washington, July 29 : Assessing the hip-bone density may help predict breast cancer risk in older, postmenopausal women.

Bone mineral density testing is done to diagnose osteoporosis and helps assess the risk of fractures.

Low bone mineral density is linked to higher risk of fractures, while normal density is linked to lower risk of fractures. It is possible that over a woman's lifetime, hormonal and other factors that lead to higher bone mineral density (and lower risk of fractures) can also lead to higher risk of breast cancer.

In the study led by Dr. Zhao Chen of the University of Arizona Mel and Enid Zuckerman College of Public Health, the team looked at nearly 10,000 post-menopausal women with an average age 63 taking part in the Women's Health Initiative.

They 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.

Over the period of 8 years, the researchers 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.

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.

Women who had the highest scores on both assessments had a much higher risk in breast cancer.

The findings suggest that adding bone mineral density to currently used risk assessment tools may significantly improve the prediction of breast cancer risk.

"Future studies should investigate whether incorporating bone mineral density and Gail score with other risk factors, such as breast density, can further improve the identification of women at high risk for developing breast cancer," the authors wrote.

The bone mineral density can also be used as an alternative tool for assessing breast cancer risk when Gail score is not available.

The new study will be published in the September 1, 2008 issue of Cancer.

ANI