Lipworth L, Katsouyanni K, Ekbom A, Michels K B, Trichopoulos D
Department of Epidemiology, Harvard School of Public Health, Boston, MA 02115, USA.
Int J Cancer. 1995 Apr 10;61(2):181-4. doi: 10.1002/ijc.2910610207.
We have examined the association between induced or spontaneous abortion and breast cancer risk in Greece. In a hospital-based case-control study in Athens, 820 patients with confirmed breast cancer were compared with 795 orthopedic patient controls and 753 healthy visitor controls, matched to cases by age and interviewer. Logistic regression was used to analyze the data, controlling for demographic, reproductive and nutritional variables. Odds ratio (OR) patterns were similar for the 2 control series, which were therefore combined to increase precision of the estimates. The risk for breast cancer was not increased for women who had a history of abortion, compared to nulliparous women with no history of abortion. Thus ORs and 95% confidence intervals were for nulliparous women with spontaneous abortion, 1.17 (0.64-2.13); for nulliparous women with induced abortion, 0.98 (0.56-1.73); for parous women with no abortion, 0.56 (0.31-1.01); for parous women with spontaneous abortion, 0.61 (0.33-1.14) and for parous women with induced abortion, 0.99 (0.56-1.74). When the analysis was restricted to parous women, using parous women with no history of abortion as the baseline, ORs and 95% confidence intervals were for induced abortion before first full-term pregnancy, 2.06 (1.45-2.90); for induced abortion after first full-term pregnancy, 1.59 (1.24-2.04) and for spontaneous abortion, 1.10 (0.82-1.40). Our findings suggest that an interrupted pregnancy does not impart the long-term protective effect of a full-term pregnancy attributable to terminal differentiation.
我们研究了希腊人工流产或自然流产与乳腺癌风险之间的关联。在雅典一项基于医院的病例对照研究中，将820例确诊乳腺癌患者与795例骨科患者对照及753例健康访客对照进行比较，对照与病例按年龄和访谈者进行匹配。采用逻辑回归分析数据，控制人口统计学、生殖和营养变量。两个对照系列的比值比（OR）模式相似，因此将它们合并以提高估计的精确度。与无流产史的未生育女性相比，有流产史的女性患乳腺癌的风险并未增加。因此，未生育且有自然流产史女性的OR及95%置信区间为1.17（0.64 - 2.13）；未生育且有人工流产史女性的OR及95%置信区间为0.98（0.56 - 1.73）；已生育且无流产史女性的OR及95%置信区间为0.56（0.31 - 1.01）；已生育且有自然流产史女性的OR及95%置信区间为0.61（0.33 - 1.14）；已生育且有人工流产史女性的OR及95%置信区间为0.99（0.56 - 1.74）。当分析仅限于已生育女性时，以无流产史的已生育女性为基线，首次足月妊娠前人工流产的OR及95%置信区间为2.06（1.45 - 2.90）；首次足月妊娠后人工流产的OR及95%置信区间为1.59（1.24 - 2.04）；自然流产的OR及95%置信区间为1.10（0.82 - 1.40）。我们的研究结果表明，妊娠中断不会赋予足月妊娠因终末分化而产生的长期保护作用。
