Parity, age at first and last birth, and risk of breast cancer: A population-based study in Sweden
Parity, age at first and last birth, and risk of breast cancer: A population-based study in Sweden
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DOI：
10.1007/bf01806150
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发表时间：
1996-01-01
影响因子：
3.8
通讯作者：
Adami, HO
中科院分区：
文献类型：
--
作者：
Lambe, M;Hsieh, CC;Adami, HO
产次与乳腺癌风险之间的关联，以及首次生育年龄和末次生育年龄对乳腺癌风险的相对重要性，在一项嵌套于1925年至1960年出生的瑞典妇女的全国队列的病例对照研究中进行了估计。共有12，782名乳腺癌女性和5倍于年龄匹配的对照组，年龄小于60岁，同时具有生育信息，被纳入分析。产次增加与乳腺癌风险显着降低相关，每增加一次分娩，风险就会降低10%（比值比0.90 [95%CI 0.88-0.91]）。在一项仅限于有两次或两次以上产次的妇女的分析中，在调整了中期生育年龄的影响后，首次生育年龄每增加5岁，乳腺癌的风险增加约13%（比值比1.13 [1.08-1.19]）。最后一次生育年龄每增加5岁，乳腺癌风险就会有轻微的增加，但具有统计学意义（比值比1.05 [1.01-1.09]）。目前的研究结果与最近的主张相矛盾，即最后一次生育年龄比第一次生育年龄对乳腺癌风险的影响更大。第一胎年龄作为风险调节因子的优势可能反映了第一次怀孕诱导的乳腺细胞终末分化所提供的保护。
Associations between parity and the risk of breast cancer, and the relative importance of age at first and age at last birth on breast cancer risk, were estimated in a case-control study nested in a nation-wide cohort of Swedish women born between 1925 and 1960. A total of 12,782 women with breast cancer and five times as many individually age-matched controls, aged less than 60 years with concomitant fertility information, were included in the analysis. Increasing parity was associated with a pronounced decrease in the risk of breast cancer with each additional birth conferring a 10 percent risk reduction (odds ratio 0.90 [95% CI 0.88-0.91]). In an analysis limited to women with two or more parities, and after adjustment for the effects of ages at interim births, the risk of breast cancer increased by about 13 percent for each five year increment in age at first birth (odds ratio 1.13 [1.08-1.19]). For every five year-increase in age at last birth there was a small risk increase of marginal statistical significance (odds ratio 1.05 [1.01-1.09]).The present findings contradict recent claims that age at last birth has a stronger effect than age at first birth on breast cancer risk. The dominance of age at first birth as risk modulator is likely to reflect the protection afforded by the terminal differentiation of breast cells induced by a first pregnancy.