Department of Epidemiology, the Graduate School of Public Health and Institute of Health and Environment, Seoul National University, Seoul, Korea.
Cancer Epidemiol Biomarkers Prev. 2010 Jun;19(6):1523-31. doi: 10.1158/1055-9965.EPI-09-1005. Epub 2010 May 25.
Both greater body size and higher mammographic density seem to be associated with a risk of breast cancer. To understand a mechanism through which body size confers a higher risk of breast cancer, associations between mammographic measures and various measures of body size were examined.
Study subjects were 730 Korean women selected from the Healthy Twin study. Body size measurements were completed according to standard protocol. Mammographic density was measured from digital mammograms using a computer-assisted method from which the total area and the dense area of the breast were calculated, and nondense area and percent of dense area were straightforwardly derived. Linear mixed models considering familial correlations were used for analyses.
Total and nondense areas were positively associated with current body mass index (BMI), BMI at 35 years, total fat percent, waist circumference, and waist-hip ratio, whereas percent dense area was inversely associated with these characteristics in both premenopausal and postmenopausal women. Height was not associated with any mammographic measure. Total and nondense areas had strong positive genetic correlations with current BMI, total fat percent, waist circumference, and waist-hip ratio, whereas percent dense area had strong inverse genetic correlations with these body size measurements.
Mammographic density and obesity are inversely associated with each other possibly from common genetic influences that have opposite effects on mammographic density and obesity in Korean women.
The association between obesity and breast cancer does not seem to be mediated through mammographic density.
更大的体型和更高的乳房密度似乎都与乳腺癌风险相关。为了了解体型如何增加乳腺癌风险的机制，研究人员检查了乳房 X 光摄影测量值与各种体型测量值之间的关联。
研究对象是从健康双胞胎研究中选择的 730 名韩国女性。根据标准方案完成体型测量。使用计算机辅助方法从数字乳房 X 光片中测量乳房密度，计算乳房的总区域和致密区域，并直接得出非致密区域和致密区域百分比。考虑家族相关性的线性混合模型用于分析。
总区域和非致密区域与当前体重指数（BMI）、35 岁时的 BMI、总脂肪百分比、腰围和腰臀比呈正相关，而绝经前和绝经后妇女的致密区域百分比与这些特征呈负相关。身高与任何乳房 X 光摄影测量值均无关联。总区域和非致密区域与当前 BMI、总脂肪百分比、腰围和腰臀比具有很强的正遗传相关性，而致密区域百分比与这些体型测量值具有很强的负遗传相关性。
乳房密度和肥胖症相互之间呈负相关，这可能是由于共同的遗传影响，这些遗传影响对韩国女性的乳房密度和肥胖症具有相反的作用。
肥胖与乳腺癌之间的关联似乎不是通过乳房 X 光摄影密度来介导的。
