A recent magazine article stated that bone mineral density (BMD) may one day pre
ID: 3071014 • Letter: A
Question
A recent magazine article stated that bone mineral density (BMD) may one day predict breast cancer risk in older women, according to a study in the Journal of the National Cancer Institute. Researchers followed the health of 8,905 women who were 65 or older and initially cancer free. Eventually 315 participants developed breast cancer. Women with the highest BMD were almost three times more likely to develop breast cancer, compared to the women with low BMD. (Better Homes and Gardens, October 2001, page 224.) (1). Do the results of this study mean that a high bone mineral density (BMD) causes breast cancer in older women? Explain your answer. (2). Explain why it is not possible to conduct a randomized experiment in this situation.
Explanation / Answer
1) Older women who have low bone mass have a decreased risk of breast cancer and conversly higher bone density is associated with increased risk of breast cancer.
Bone mineral density can be accurate marker of body response to oestrogen in that women with higher bone density are thought to be physiologically more sensitive to the hormone effects than women with lower bone density. Because oestrogen have also been linked to breast cancer.
2) It is not possible to conduct a randomised experiment in this situation because bone mineral density is one of the most powerful predictors of breast cancer especially advanced breast cancer among elderly women.