哺乳与子宫内膜癌关系的病例对照研究

目的探讨哺乳对子宫内膜癌发生的影响.方法采用病例对照研究方法,对1997年1月～2001年12月确诊的30～69岁、有上海市区户口的832例子宫内膜癌病例与随机抽取的846例全人群对照进行生育及哺乳史的调查,取其中有活产史的病例754例和对照805例,采用非条件logistic回归分析,调整可能的混杂因素,以评估哺乳对子宫内膜癌发生的比数比和95%可信区间.结果在有活产史的妇女中,哺乳者患子宫内膜癌的危险低于从未哺乳者,OR=0.76,95%CI:0.56～1.03.随着累积哺乳月数和每次活产平均哺乳月数的增加,发生子宫内膜癌的危险呈显著的下降趋势(趋势检验P值分别为0.05和＜0.01).这种下降趋势亦见于末次哺乳年龄与子宫内膜癌的联系中,而且随着停止哺乳年数的增加,哺乳的保护作用下降.未见哺乳与活产次数的交互作用.结论哺乳,尤其是近期哺乳,有可能降低子宫内膜癌的发病危险.

Lactation and the risk of endometrial cancer-a population-based casecontrol study in shanghai women

Objective To test the hypothesis that breastfeeding may decrease the risk of endometrial cancer. Methods During the period of January 1997 and December 2001, a population-based case-control study was conducted in urban shanghai to evaluate the association of lactation with endometrial cancer risk. In-person interviews were completed for 832 women newly diagnosed with endometrial cancer at ages 30 to 69 and 846 controls frequency-matched to cases on age to attain their reproductive histories and breast feeding experiences. For 754 parous cases and 805 parous controls, unconditional logistic regression models were used in the analysis to adjust potenital confounders and obtain maximum likelihood estimates of the odds ratios (ORs) and 95% confidence intervals (CIs) after adjusting for potential confounders. Results A significant inverse association between lactation and endometrial cancer risk was observed among parous women, with adjusted OR = 0. 76, 95% CI: 0. 56-1. 03. Increasing duration of lactation,measured either by lifetime duration of lactation or by months of breastfeeding per live birth, was associated with decreased risk of the disease (P for trend were 0. 05 and <0. 01, respectively). Older age at cessation of breastfeeding practice elicited protective effect on the risk of endometrial cancer. More recent breastfeeding was related to significantly reduced risks and the apparent protective effect waned with increasing time since cessation of breastfeeding. Joint effect of breastfeeding and number of live birth, however, was not observed in our study. Conclusion Our study suggests that breastfeeding, especially recent lactation among parous women in Shanghai, may reduce the risk of endometrial cancer.