Maskarinec G, Meng L, Ursin G
Cancer Research Center of Hawaii, Honolulu, Hawaii 96813, USA.
Int J Epidemiol. 2001 Oct;30(5):959-65. doi: 10.1093/ije/30.5.959.
Breast cancer incidence is considerably lower among Japanese and Chinese women than among Caucasian and Native Hawaiian even in second and third generation migrants. Mammographic densities, which refer to the radiological appearance of the healthy female breast, are related to breast cancer risk. The purpose of this project was to explore the hypothesis that women from ethnic groups at high breast cancer risk are more likely to have high levels of densities than women from low breast cancer risk groups.
In a cross-sectional design, 514 pre- and post-menopausal women recruited at mammography screening clinics completed a self-administered questionnaire. We used a computer-assisted method to measure the dense and the total areas of the breast and to compute per cent breast density. Student's t-tests and multiple linear regression were applied to examine ethnic differences and to explore determinants of mammographic densities, respectively.
The unadjusted mean dense area was 15% smaller in Chinese and Japanese women than in the Caucasian/Hawaiian group. However, because of their smaller breast size, the per cent of the breast occupied by dense tissue in Chinese and Japanese women was 20% higher than in Caucasian women. Body mass index, age, menopausal status, parity, and oestrogen therapy were associated with mammographic densities, but they did not account for all ethnic differences.
Whereas this study detected some ethnic differences in mammographic densities, the importance of dense areas and per cent densities as indicators of breast cancer risk in ethnically diverse populations remains to be clarified.
即使在第二代和第三代移民中，日本和中国女性的乳腺癌发病率也远低于白种人和夏威夷原住民女性。乳腺X线摄影密度指健康女性乳房的放射学表现，与乳腺癌风险相关。本项目的目的是探讨以下假设：乳腺癌风险高的种族群体中的女性比乳腺癌风险低的群体中的女性更有可能具有高水平的密度。
在一项横断面设计中，在乳腺X线摄影筛查诊所招募的514名绝经前和绝经后女性完成了一份自我管理的问卷。我们使用计算机辅助方法测量乳房的致密区域和总面积，并计算乳房密度百分比。分别应用学生t检验和多元线性回归来检验种族差异并探索乳腺X线摄影密度的决定因素。
中国和日本女性未经调整的平均致密区域比白种人/夏威夷人群体小15%。然而，由于她们的乳房尺寸较小，中国和日本女性乳房中致密组织所占的百分比比白种人女性高20%。体重指数、年龄、绝经状态、生育史和雌激素治疗与乳腺X线摄影密度相关，但它们并不能解释所有的种族差异。
尽管本研究发现了乳腺X线摄影密度方面的一些种族差异，但致密区域和密度百分比作为不同种族人群乳腺癌风险指标的重要性仍有待阐明。
