Campbell Family Institute for Breast Cancer Research, Ontario Cancer Institute, 610 University Avenue, Toronto, Ontario M5G 2K9, Canada.
Breast Cancer Res. 2010;12(1):R2. doi: 10.1186/bcr2465. Epub 2010 Jan 6.
Striking differences exist between countries in the incidence of breast cancer. The causes of these differences are unknown, but because incidence rates change in migrants, they are thought to be due to lifestyle rather than genetic differences. The goal of this cross-sectional study was to examine breast cancer risk factors in populations with different risks for breast cancer.
We compared breast cancer risk factors among three groups of postmenopausal Canadian women at substantially different risk of developing breast cancer - Caucasians (N = 413), Chinese women born in the West or who migrated to the West before age 21 (N = 216), and recent Chinese migrants (N = 421). Information on risk factors and dietary acculturation were collected by telephone interviews using questionnaires, and anthropometric measurements were taken at a home visit.
Compared to Caucasians, recent Chinese migrants weighed on average 14 kg less, were 6 cm shorter, had menarche a year later, were more often parous, less often had a family history of breast cancer or a benign breast biopsy, a higher Chinese dietary score, and a lower Western dietary score. For most of these variables, Western born Chinese and early Chinese migrants had values intermediate between those of Caucasians and recent Chinese migrants. We estimated five-year absolute risks for breast cancer using the Gail Model and found that risk estimates in Caucasians would be reduced by only 11% if they had the risk factor profile of recent Chinese migrants for the risk factors in the Gail Model.
Our results suggest that in addition to the risk factors in the Gail Model, there likely are other factors that also contribute to the large difference in breast cancer risk between Canada and China.
乳腺癌的发病率在各国之间存在显著差异。这些差异的原因尚不清楚，但由于移民中的发病率发生了变化，因此认为这些差异是由于生活方式而不是遗传差异造成的。本横断面研究的目的是研究具有不同乳腺癌风险的人群中的乳腺癌危险因素。
我们比较了三组处于不同乳腺癌风险的绝经后加拿大女性的乳腺癌危险因素-白种人（N=413），在 21 岁之前在西方出生或移民到西方的中国女性（N=216）和最近的中国移民（N=421）。通过电话访谈使用问卷收集有关危险因素和饮食适应的信息，并在家庭访问中进行人体测量。
与白种人相比，最近的中国移民平均体重轻 14 公斤，身高低 6 厘米，月经初潮晚一年，生育更多，家族史乳腺癌或良性乳腺活检较少，中国饮食评分较高，西方饮食评分较低。对于这些变量中的大多数，西方出生的中国人和早期的中国移民的数值介于白种人和最近的中国移民之间。我们使用 Gail 模型估计了乳腺癌的五年绝对风险，发现如果白种人具有最近的中国移民的风险因素概况，即 Gail 模型中的风险因素，则风险估计值将仅降低 11％。
我们的结果表明，除了 Gail 模型中的危险因素外，可能还有其他因素也导致加拿大和中国之间乳腺癌风险存在巨大差异。
