Michels Karin B, Xue Fei, Terry Kathryn L, Willett Walter C
Obstetrics and Gynecology Epidemiology Center, Channing Laboratory, Brigham and Women's Hospital, Harvard Medical School, Boston, MA 02115, USA.
Carcinogenesis. 2006 Dec;27(12):2464-8. doi: 10.1093/carcin/bgl105. Epub 2006 Jun 15.
A high birthweight has been associated with an increased risk of breast cancer later in life. The role of adult variables, possible effect modifiers and cancer characteristics has been little studied. We explored these in two large prospective cohort studies of women, the Nurses' Health Study (NHS) and the Nurses' Health Study II (NHS II). We collected information on birthweight from 152,608 female nurses participating in NHS and NHS II. During 10 years and 1.3 million person-years of follow-up, invasive breast cancer was newly diagnosed among 828 premenopausal and 2312 postmenopausal women. Data were analyzed using a Cox proportional hazards model. Premenopausal women with a birthweight of <5.5 lbs had a covariate-adjusted hazard ratio (HR) for breast cancer of 0.66 [95% confidence interval (CI) 0.47-0.93] compared with women born at 8.5 lbs or above. Adult height was the only factor explaining some of the association between birthweight and breast cancer incidence; after adjustment for height the HR was 0.73 (95% CI 0.51-1.03). The association between birthweight and the incidence of breast cancer was stronger among women with estrogen-receptor positive and progesterone-receptor positive breast cancer. Among postmenopausal women, no important association between the birthweight and the incidence of breast cancer was detected (HR comparing women with a birthweight of 5.5 lbs or less with women with a birthweight>8.5 lbs: 0.97; 95% CI 0.80-1.16). In these two large prospective cohorts, a low birthweight was associated with a decreased incidence of breast cancer among premenopausal women. This association was independent of other factors operating later in life, except for adult height.
出生体重高与日后患乳腺癌的风险增加有关。成人变量、可能的效应修饰因素和癌症特征的作用鲜有研究。我们在两项针对女性的大型前瞻性队列研究——护士健康研究（NHS）和护士健康研究II（NHS II）中对此进行了探究。我们收集了参与NHS和NHS II的152,608名女性护士的出生体重信息。在10年、130万人年的随访期间，828名绝经前女性和2312名绝经后女性被新诊断出浸润性乳腺癌。数据采用Cox比例风险模型进行分析。出生体重<5.5磅的绝经前女性患乳腺癌的协变量调整风险比（HR）为0.66[95%置信区间（CI）0.47 - 0.93]，而出生体重在8.5磅及以上的女性相比。成人身高是解释出生体重与乳腺癌发病率之间部分关联的唯一因素；调整身高后，HR为0.73（95% CI 0.51 - 1.03）。出生体重与雌激素受体阳性和孕激素受体阳性乳腺癌女性的乳腺癌发病率之间的关联更强。在绝经后女性中，未检测到出生体重与乳腺癌发病率之间存在重要关联（出生体重≤5.5磅的女性与出生体重>8.5磅的女性相比的HR：0.97；95% CI 0.80 - 1.16）。在这两项大型前瞻性队列研究中，低出生体重与绝经前女性乳腺癌发病率降低有关。这种关联独立于生命后期起作用的其他因素，但成人身高除外。
