Wingo P A, Newsome K, Marks J S, Calle E E, Parker S L
Epidemiology and Surveillance Research Department, American Cancer Society, Atlanta, GA 30329-4251, USA.
Cancer Causes Control. 1997 Jan;8(1):93-108. doi: 10.1023/a:1018443507512.
To evaluate the relationship between breast cancer risk and spontaneous and induced abortion, we conducted a detailed descriptive review of 32 epidemiologic studies that provided data by type of abortion and by various measures of exposure to abortion-number of abortions, timing of abortion in relation to first full-term pregnancy, length of gestation, and age at first abortion. Breast cancer risk did not appear to be associated with an increasing number of spontaneous or induced abortions. Our review also suggested that breast cancer risk probably was not related to the other measures of exposure to abortion, and probably did not differ by age or a family history of breast cancer. Finally, the data appeared to suggest a slightly increased risk among nulliparous women, but this tendency was based primarily on studies with a small number of nulliparous women who had had spontaneous or induced abortions. Definitive conclusions about an association between breast cancer risk and spontaneous or induced abortion are not possible at present because of inconsistent findings across studies. Future investigations should consider prospective designs, separate analyses of spontaneous and induced abortions, appropriate referent groups, and adequate adjustment for confounding and effect modification. Future investigations also should attempt to determine whether any increased risks reflect the transient increase in breast cancer risk hypothesized for full-term pregnancy or a causal relationship specific to spontaneous or induced abortion.
为评估乳腺癌风险与自然流产和人工流产之间的关系，我们对32项流行病学研究进行了详细的描述性综述，这些研究按流产类型以及流产暴露的各种衡量指标——流产次数、流产时间与首次足月妊娠的关系、妊娠时长以及首次流产时的年龄——提供了数据。乳腺癌风险似乎与自然流产或人工流产次数的增加无关。我们的综述还表明，乳腺癌风险可能与其他流产暴露衡量指标无关，并且可能不因年龄或乳腺癌家族史而有所不同。最后，数据似乎表明未生育女性的风险略有增加，但这种趋势主要基于对少数有自然流产或人工流产史的未生育女性的研究。由于各项研究结果不一致，目前尚无法就乳腺癌风险与自然流产或人工流产之间的关联得出明确结论。未来的调查应考虑前瞻性设计、对自然流产和人工流产进行单独分析、合适的参照组以及对混杂因素和效应修正进行充分调整。未来的调查还应尝试确定任何增加的风险是否反映了为足月妊娠假设的乳腺癌风险的短暂增加，或者是否反映了自然流产或人工流产特有的因果关系。
