Framingham Data Links High Bone Mass And Breast Cancer

New data from the Framingham study has suggested that bone mass, takenas a measure of a women's exposure to estrogen over her lifetime, can be predictive of who is at risk of developing breast cancer.

The study, reported in the New England Journal of Medicine (February 27), found that women in the highest quartile of bone mass were at a significantly higher risk of breast cancer than those in the lowest quartile. The authors conclude that "the mechanisms underlying this relation are not understood, but cumulative exposure to estrogen may play a part." This could raise questions for women who take hormone replacement therapy, but the US National Osteoporosis Foundation stresses that the study examined endogenous estrogen, rather than HRT use.

"There are many factors that influence attaining maximum bone mass besides estrogen, and more study is needed before bone densitometry can be recommended as a tool to assess natural estrogen exposure and breast cancer risk," said Robert Lindsay, NOF president. Even in the upper quartile, the risk of breast cancer is low in comparison to the risk of osteoporosis in the group with low bone mass, he said.