Ganry O, Baudoin C, Fardellone P, Peng J, Raverdy N
Medical Information, Epidemiology and Biostatistics, Amiens University Hospital, France.
Eur J Epidemiol. 2004;19(8):785-92. doi: 10.1023/b:ejep.0000036567.60387.39.
Older women with high bone mineral density (BMD) have an increased risk of breast cancer but it is not well known whether this association is associated with the stage of the tumor. The objective of the study is to determine if older women with high BMD are likely to develop a more aggressive form of breast cancer, as defined by mortality.
We prospectively studied 1504 women who were 75 years of age or older at the entry in the study (range, 75-90 years), between 1992 and 1994. BMD was measured by dual-photon X-ray absorptiometry at three skeletal sites (trochanter, Ward's triangle, femoral neck). The women were followed for a mean of 7 years for the occurrence of breast cancer. Cox proportional-hazards models were used to obtain estimates of the relative risk of breast cancer and relative risk of death according to the BMD.
Forty-five incident breast cancer cases were identified. In multivariate analyses of the risk of breast cancer for women in the highest tertile of BMD was greater than for women in the lowest tertile. Indeed, the women with a trochanter BMD in the highest tertile were at 2.3-fold increased risk compared with women in the lowest tertile. The women with highest tertile BMD measured at the Ward's triangle and at the femoral neck were respectively at 2.2-and 3.3-fold increased risk compared with women at the lowest risk. The 7-year survival rates were markedly less favorable for women in the second and third tertile of the three skeletal sites compared with the lowest tertile. The risk of death was greater for women in the highest tertile of BMD than for women in the lowest tertile at every skeletal site.
Elderly women with high BMD have an increased risk of breast cancer, especially advanced cancer, compared with women with low BMD.
骨矿物质密度（BMD）高的老年女性患乳腺癌的风险增加，但这种关联是否与肿瘤分期有关尚不清楚。本研究的目的是确定骨密度高的老年女性是否更有可能发展为一种更具侵袭性的乳腺癌，以死亡率来定义。
我们对1992年至1994年间纳入研究时年龄在75岁及以上（范围为75 - 90岁）的1504名女性进行了前瞻性研究。通过双能X线吸收法在三个骨骼部位（大转子、沃德三角、股骨颈）测量骨密度。对这些女性随访平均7年以观察乳腺癌的发生情况。使用Cox比例风险模型来估计根据骨密度的乳腺癌相对风险和死亡相对风险。
共确定了45例新发乳腺癌病例。在多变量分析中，骨密度处于最高三分位数的女性患乳腺癌的风险高于最低三分位数的女性。实际上，大转子骨密度处于最高三分位数的女性与最低三分位数的女性相比，风险增加了2.3倍。在沃德三角和股骨颈处骨密度处于最高三分位数的女性与风险最低的女性相比，风险分别增加了2.2倍和3.3倍。三个骨骼部位中处于第二和第三三分位数的女性的7年生存率明显低于最低三分位数的女性。在每个骨骼部位，骨密度处于最高三分位数的女性的死亡风险都高于最低三分位数的女性。
与骨密度低的女性相比，骨密度高的老年女性患乳腺癌尤其是晚期癌症的风险增加。
