a Food Science and Nutrition, University of Minnesota , St. Paul , Minnesota , USA.
Nutr Cancer. 2013;65(7):969-81. doi: 10.1080/01635581.2013.815787. Epub 2013 Oct 15.
Prolonged lactation (≥24 mo) has been associated with reduced breast cancer risk. This research examined this association in postmenopausal women in the Women's Health Initiative (WHI) Hormone Trial (HT) and Observational Study (OS). This retrospective cohort analysis included 69,358 predominantly overweight (65.4%), white (83.2%) postmenopausal women without breast cancer. Women in the HT were randomized to 0.625 mg conjugated equine estrogen (CEE), 0.625 CEE + 2.5 mg medroxyprogesterone acetate (CEE/MPA), or placebo. OS participants had no restrictions on hormone use. Lactation history was assessed via WHI Reproductive History Questionnaire. Most women breastfed at least 1 mo (58.0%); 35.4% breastfed 1-2 children; and 6.5% stated having breastfed ≥24mo. Women in the HT-CEE who breastfed their first child between 20-24 yr of age demonstrated a nonsignificant decreased risk of breast cancer (HR: 0.62; 95% CI: 0.38, 1.01). OS participants who reported CEE/MPA hormone use and age of first breastfeeding ≥30 yr showed a significant increased risk of breast cancer (HR: 1.66; 95% CI: 1.14, 2.41). Risk was increased if age of last breastfeeding was ≥35yr (HR: 1.50; 95% CI: 1.05, 2.14). This research did not demonstrate a significantly decreased risk of postmenopausal breast cancer in women who breastfed for ≥24 mo during their lifetime.
延长哺乳期（≥24 个月）与降低乳腺癌风险有关。这项研究在女性健康倡议（WHI）激素试验（HT）和观察研究（OS）中检查了绝经后妇女的这种关联。这项回顾性队列分析包括 69358 名主要超重（65.4%）、白人（83.2%）、无乳腺癌的绝经后妇女。HT 中的女性被随机分配到 0.625 毫克结合马雌激素（CEE）、0.625 CEE + 2.5 毫克醋酸甲羟孕酮（CEE/MPA）或安慰剂。OS 参与者没有激素使用限制。哺乳史通过 WHI 生殖史问卷进行评估。大多数女性至少母乳喂养 1 个月（58.0%）；35.4%母乳喂养 1-2 个孩子；6.5%表示母乳喂养≥24 个月。HT-CEE 中首次母乳喂养年龄在 20-24 岁的女性乳腺癌风险呈非显著降低（HR：0.62；95%CI：0.38，1.01）。报告使用 CEE/MPA 激素和首次母乳喂养年龄≥30 岁的 OS 参与者显示乳腺癌风险显著增加（HR：1.66；95%CI：1.14，2.41）。如果最后一次母乳喂养年龄≥35 岁，则风险增加（HR：1.50；95%CI：1.05，2.14）。这项研究没有表明在一生中母乳喂养≥24 个月的绝经后妇女患乳腺癌的风险显著降低。
