Hahn R A, Moolgavkar S H
Division of Surveillance and Epidemiologic Studies, Centers for Disease Control, Atlanta, GA 30333.
Am J Public Health. 1989 Nov;79(11):1503-7. doi: 10.2105/ajph.79.11.1503.
Risk of breast cancer increases with age at first birth, and is lower in women who bear their first children while young than in nulliparous women. While previous studies have investigated risk of breast cancer in birth cohorts by examining partial aspects of cohort childbearing, the present ecological study assesses total cohort childbearing risk in Connecticut women born between 1855 and 1945. In each cohort, the proportion of women nulliparous and first bearing children in their twenties, thirties, and forties are weighted by relative risks associated with these events as ascertained in previous studies. Summed cohort childbearing risks are compared to the incidence of breast cancer in women 40 years of age and older in the same cohorts. Changes in decade of first birth and nulliparity do not explain the changes in breast cancer incidence observed: while cohort childbearing risk has declined over the period examined, breast cancer incidence has increased in the same cohorts. Alternative explanations for cohort increases in breast cancer incidence are reviewed.
乳腺癌风险随首次生育年龄的增长而增加，在年轻时生育第一胎的女性中，其风险低于未生育女性。虽然先前的研究通过考察队列生育的部分方面来调查出生队列中的乳腺癌风险，但本生态学研究评估了1855年至1945年出生的康涅狄格州女性的总体队列生育风险。在每个队列中，未生育女性以及在二十多岁、三十多岁和四十多岁生育第一胎的女性比例，根据先前研究确定的与这些事件相关的相对风险进行加权。将队列生育风险总和与同队列中40岁及以上女性的乳腺癌发病率进行比较。首次生育和未生育十年的变化并不能解释所观察到的乳腺癌发病率变化：在所研究的时间段内，队列生育风险下降，而同一队列中的乳腺癌发病率却上升了。本文回顾了队列中乳腺癌发病率上升的其他解释。
