Department of Epidemiology, University of Florida, College of Public Health and Health Professions and College of Medicine, Gainesville, Florida.
Department of Epidemiology, Harvard T.H. Chan School of Public Health, Boston, Massachusetts.
Cancer Epidemiol Biomarkers Prev. 2024 Jun 3;33(6):804-811. doi: 10.1158/1055-9965.EPI-23-1318.
We investigated the associations between several reproductive factors related to childbearing and the variation (V) measure (a novel, objective, single summary measure of breast image intensity) by menopausal status.
Our study included 3,814 cancer-free women within the Nurses' Health Study (NHS) and NHSII cohorts. The data on reproductive variables and covariates were obtained from biennial questionnaires closest to the mammogram date. V-measures were obtained from mammographic images using a previously developed algorithm capturing the standard deviation of pixel values. We used multivariate linear regression to examine the associations of parity, age at first birth, time between menarche and first birth, time since last pregnancy, and lifetime breastfeeding duration with V-measure, adjusting for breast cancer risk factors, including the percentage of mammographic density (PMD). We further examined whether these associations were statistically accounted for (mediated) by PMD.
Among premenopausal women, none of the reproductive factors were associated with V. Among postmenopausal women, inverse associations of parity and positive associations of age at first birth with V were mediated by PMD (percent mediated: nulliparity: 66.7%, P < 0.0001; parity: 50.5%, P < 0.01; age at first birth 76.1%, P < 0.001) and were no longer significant in PMD-adjusted models. Lifetime duration of breastfeeding was positively associated with V [>36 vs. 0 ≤1 months β = 0.29; 95% confidence interval (CI) 0.07; 0.52, Ptrend < 0.01], independent of PMD.
Parity, age at first birth, and breastfeeding were associated with postmenopausal V.
This study highlights associations of reproductive factors with mammographic image intensity.
我们研究了与生育相关的几种生殖因素与绝经状态之间的关联（V 度量（一种新的、客观的、单一的乳房图像强度综合指标））。
我们的研究包括了护士健康研究（NHS）和 NHSII 队列中的 3814 名无癌症的女性。生殖变量和协变量的数据是从最接近乳房 X 光日期的两年一次的问卷中获得的。V 度量是从乳房 X 光图像中使用以前开发的算法获得的，该算法捕捉了像素值的标准偏差。我们使用多元线性回归来研究生育次数、首次生育年龄、初潮与首次生育的时间间隔、上次怀孕时间和终生母乳喂养时间与 V 度量的关系，同时调整了乳腺癌风险因素，包括乳腺密度百分比（PMD）。我们进一步研究了这些关联是否通过 PMD 进行了统计学上的解释（中介）。
在绝经前女性中，没有一种生殖因素与 V 相关。在绝经后女性中，生育次数与 V 的反比关系以及首次生育年龄与 V 的正相关关系通过 PMD 进行了中介（中介百分比：未生育：66.7%，P<0.0001；生育：50.5%，P<0.01；首次生育年龄：76.1%，P<0.001），并且在 PMD 调整后的模型中不再显著。终生母乳喂养时间与 V 呈正相关[>36 个月与 0≤1 个月β=0.29；95%置信区间（CI）0.07；0.52，Ptrend<0.01]，独立于 PMD。
生育次数、首次生育年龄和母乳喂养与绝经后 V 相关。
本研究强调了生殖因素与乳房 X 光图像强度之间的关联。
