Division of Epidemiology, Department of Medicine, Vanderbilt University School of Medicine, Nashville, Tennessee 37203-1738, USA.
Am J Epidemiol. 2010 Oct 15;172(8):962-70. doi: 10.1093/aje/kwq263. Epub 2010 Sep 21.
Fetal growth or gestational age in a woman's pregnancies may modify pregnancy-related breast cancer risk, yet studies of these exposures are few. The authors conducted a population-based case-control study among parous Michigan women aged ≤50 years using linked Michigan Cancer Registry (1985-2004) and Michigan livebirth records (1978-2004). Breast cancer cases (n = 7,591) were matched 1:4 to controls (n = 28,382) on maternal birth year and race. Using conditional logistic regression, the authors examined the associations of gestational age (in weeks) and fetal growth (defined using birth weight percentiles for gestational age) in first and last births with breast cancer risk. Having a small-for-gestational-age or large-for-gestational-age infant at a maternal first or last birth was not associated with breast cancer risk, but having a small-for-gestational-age infant at a last birth at ≥30 years modestly reduced risk: odds ratio = 0.82 (95% confidence interval: 0.68, 0.98). First delivery at <32 or >41 weeks also modestly reduced risk: odds ratio = 0.80 (95% confidence interval: 0.62, 1.04) or 0.92 (95% confidence interval: 0.85, 0.99), respectively. In the largest case-control study to date, fetal growth was not associated with overall breast cancer risk in women aged ≤50, and there was some evidence for reduced breast cancer risk for early or late gestational age in first births only.
在女性妊娠中，胎儿生长或胎龄可能会改变与妊娠相关的乳腺癌风险，但针对这些暴露因素的研究很少。作者在密歇根州进行了一项基于人群的病例对照研究，纳入了年龄≤50 岁的多产妇密歇根州妇女，使用了密歇根癌症登记处（1985-2004 年）和密歇根州活产记录（1978-2004 年）进行了链接。乳腺癌病例（n=7591）按产妇出生年份和种族与对照组（n=28382）1:4 匹配。作者使用条件逻辑回归，检查了首次和末次妊娠的胎龄（周）和胎儿生长（使用胎龄的出生体重百分位定义）与乳腺癌风险的关系。首次或末次妊娠的胎儿小于胎龄或大于胎龄与乳腺癌风险无关，但末次妊娠≥30 岁时胎儿小于胎龄会适度降低风险：比值比=0.82（95%置信区间：0.68, 0.98）。首次分娩<32 周或>41 周也适度降低风险：比值比=0.80（95%置信区间：0.62, 1.04）或 0.92（95%置信区间：0.85, 0.99）。在迄今为止最大的病例对照研究中，在≤50 岁的女性中，胎儿生长与总体乳腺癌风险无关，并且仅在首次妊娠中存在早期或晚期胎龄与降低乳腺癌风险的一些证据。
