Talamini R, Franceschi S, La Vecchia C, Negri E, Borsa L, Montella M, Falcini F, Conti E, Rossi C
Servizio di Epidemiologia, Centro di Riferimento Oncologico, Aviano, Italy.
Eur J Cancer. 1996 Feb;32A(2):303-10. doi: 10.1016/0959-8049(95)00615-x.
The aim of the study was to elucidate the role of reproductive and menstrual factors in the aetiology of breast cancer, overall and by menopausal status. A cooperative case-control study was conducted between 1991 and 1994 in six different Italian areas (including three from the centre and the south). The study included 2569 histologically confirmed incident cases of breast cancer (median age 55 years, range 23-78 years) and 2588 control women (median age 56 years, range 20-79 years) admitted to the same hospitals for a variety of acute conditions unrelated to the hypotheses in study. A trend of increasing risk with increasing age at menopause (odds ratio (OR) for age at menopause > or = 53 versus < 45 years = 1.8; 95% confidence interval (CI) = 1.4-2.2). High parity reduced cancer risk (OR for > or = 4 versus 1 birth = 0.7; 95% CI = 0.5-0.9). Overall, nulliparous women showed a 20% lower risk than uniparous ones (OR = 0.8; 95% CI = 0.7-1.0). Late age at first birth (or pregnancy) had an independent adverse effect (OR for first birth at > or = 32 versus < 20 years = 1.7; 95% CI = 1.3-2.1) both before and after menopause. An approximately 2-fold elevation of breast cancer risk was evident up to 10 years after the last birth. No trend in risk was evident for induced abortions (OR = 1.2 for 1 and 1.1 for > or = 2 induced abortions versus 0). Other examined menstrual and reproductive characteristics did not seem important. Multiparity, early age at first birth and early age at menopause were therefore the most important determinants of breast cancer risk. The effects of the timing of births was significantly heterogeneous in pre- and postmenopausal women because of the transient adverse effect of such events, evident only in premenopausal women.
本研究的目的是阐明生殖和月经因素在乳腺癌病因中的作用，包括总体情况以及按绝经状态分析。1991年至1994年期间，在意大利六个不同地区（包括来自中部和南部的三个地区）开展了一项合作病例对照研究。该研究纳入了2569例经组织学确诊的乳腺癌新发病例（中位年龄55岁，范围23 - 78岁）和2588名对照女性（中位年龄56岁，范围20 - 79岁），这些对照女性因各种与研究假设无关的急性疾病入住同一医院。绝经年龄越大，风险呈上升趋势（绝经年龄≥53岁与＜45岁相比的优势比（OR）= 1.8；95%置信区间（CI）= 1.4 - 2.2）。高生育次数降低了癌症风险（生育次数≥4次与1次相比的OR = 0.7；95% CI = 0.5 - 0.9）。总体而言，未生育女性的风险比生育一次的女性低20%（OR = 0.8；95% CI = 0.7 - 1.0）。首次生育（或怀孕）年龄较大有独立的不良影响（首次生育年龄≥32岁与＜20岁相比的OR = 1.7；95% CI = 1.3 - 2.1），在绝经前后均如此。最后一次生育后长达10年，乳腺癌风险明显升高约2倍。人工流产方面未见风险趋势（人工流产1次的OR = 1.2，人工流产≥2次的OR = 1.1，与0次相比）。其他检查的月经和生殖特征似乎并不重要。因此，多生育、早育和早绝经是乳腺癌风险的最重要决定因素。由于生育时间的影响仅在绝经前女性中明显存在且具有短暂的不良影响，所以生育时间对绝经前和绝经后女性的影响存在显著差异。
