Physical Activity and Change in Mammographic Density
Physical Activity and Change in Mammographic Density
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DOI：
10.1093/aje/kwq025
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发表时间：
2010-05-01
影响因子：
5
通讯作者：
Habel, Laurel A.
中科院分区：
文献类型：
--
作者：
Conroy, Shannon M.;Butler, Lesley M.;Habel, Laurel A.
体力活动可能预防乳腺癌的一个潜在机制是降低乳房X光照相密度。乳房X光摄影密度百分比，即致密的乳房组织面积占总乳房面积的比例，随着年龄的增长而下降，是乳腺癌的强烈风险因素。作者假设，与身体活动较少的女性相比，身体活动较多的女性随着年龄的增长，乳房X光检查密度的百分比下降幅度会更大。作者使用全国妇女健康研究(SWAN)中722名参与者的纵向数据(1996-2004)验证了这一假设，SWAN是一组在基线水平处于绝经前和绝经早期的多民族妇女队列，采用多变量、重复测量的线性回归分析。在平均5.6年的时间里，乳房X光摄影密度百分比的平均年降幅为1.1%(标准差=0.1)。总体力活动得分每增加1个单位，乳房X光摄影密度百分比的年降幅较小，降幅为0.09%(标准误差=0.03；P=0.01)。体力活动与非致密乳房面积的变化呈负相关(P<；0.01)，与致密乳房面积的变化无关(P=0.17)。研究结果不支持这样一种假设，即体育锻炼通过包括降低乳房X光照相密度在内的机制来减少乳腺癌。
One potential mechanism by which physical activity may protect against breast cancer is by decreasing mammographic density. Percent mammographic density, the proportion of dense breast tissue area to total breast area, declines with age and is a strong risk factor for breast cancer. The authors hypothesized that women who were more physically active would have a greater decline in percent mammographic density with age, compared with less physically active women. The authors tested this hypothesis using longitudinal data (1996-2004) from 722 participants in the Study of Women's Health Across the Nation (SWAN), a multiethnic cohort of women who were pre- and early perimenopausal at baseline, with multivariable, repeated-measures linear regression analyses. During an average of 5.6 years, the mean annual decline in percent mammographic density was 1.1% (standard deviation = 0.1). A 1-unit increase in total physical activity score was associated with a weaker annual decline in percent mammographic density by 0.09% (standard error = 0.03; P = 0.01). Physical activity was inversely associated with the change in nondense breast area (P < 0.01) and not associated with the change in dense breast area (P = 0.17). Study results do not support the hypothesis that physical activity reduces breast cancer through a mechanism that includes reduced mammographic density.