Department of Epidemiology, University of Florida, College of Public Health and Health Professions and College of Medicine, Gainesville, Florida.
Cancer Epidemiology Department, Moffitt Cancer Center & Research Institute, Tampa, Florida.
Cancer Epidemiol Biomarkers Prev. 2022 Feb;31(2):436-442. doi: 10.1158/1055-9965.EPI-21-0853. Epub 2021 Dec 3.
We investigated the associations of oral contraceptives (OC) with percent breast density (PD), absolute dense area (DA), nondense area (NDA), and a novel image intensity variation (V) measure in premenopausal women.
This study included 1,233 controls from a nested case-control study within Nurses' Health Study II cohort. Information on OCs was collected in 1989 and updated biennially. OC use was defined from the questionnaire closest to the mammogram date. PD, DA, and NDA were measured from digitized film mammograms using a computer-assisted thresholding technique; the V measure was obtained with a previously developed algorithm measuring the SD of pixel values in the eroded breast region. Generalized linear regression was used to assess associations between OCs and density measures (square root-transformed PD, DA, and NDA, and -untransformed V).
OC use was not associated with PD [current vs. never: β = -0.06; 95% confidence interval (CI), -0.37-0.24; past vs. never: β = 0.10; 95% CI, -0.09-0.29], DA (current vs. never: β = -0.20; 95% CI -0.59-0.18; past vs. never: β = 0.13; 95% CI, -0.12-0.39), and NDA (current vs. never: β = -0.19; 95% CI, -0.56-0.18; past vs. never: β = -0.01; 95% CI, -0.28-0.25). Women with younger age at initiation had significantly greater V-measure (<20 years vs. never: β = 26.88; 95% CI, 3.18-50.58; 20-24 years vs. never: β = 20.23; 95% CI, -4.24-44.71; 25-29 years vs. never: β = 2.61; 95% CI -29.00-34.23; ≥30 years vs. never: β = 0.28; 95% CI, -34.16-34.72, = 0.03).
Our findings suggest that an earlier age at first OC use was associated with significantly greater V.
These findings could guide decisions about the age for OC initiation.
我们研究了口服避孕药 (OC) 与绝经前妇女的乳腺密度百分比 (PD)、绝对致密区 (DA)、非致密区 (NDA) 和新的图像强度变化 (V) 测量值之间的关联。
这项研究包括来自护士健康研究 II 队列的嵌套病例对照研究中的 1233 名对照者。OC 信息于 1989 年收集，并每两年更新一次。OC 使用情况根据最接近乳房 X 光片拍摄日期的问卷确定。PD、DA 和 NDA 是从数字化胶片乳房 X 光片中使用计算机辅助阈值技术测量的；V 测量值是使用以前开发的算法测量侵蚀性乳房区域的像素值的 SD 获得的。广义线性回归用于评估 OC 与密度测量值（平方根转换的 PD、DA 和 NDA，以及未转换的 V）之间的关联。
OC 使用与 PD 无关 [当前 vs. 从未：β=-0.06；95%置信区间 (CI)，-0.37-0.24；过去 vs. 从未：β=0.10；95%CI，-0.09-0.29]、DA（当前 vs. 从未：β=-0.20；95%CI，-0.59-0.18；过去 vs. 从未：β=0.13；95%CI，-0.12-0.39）和 NDA（当前 vs. 从未：β=-0.19；95%CI，-0.56-0.18；过去 vs. 从未：β=-0.01；95%CI，-0.28-0.25）。起始年龄较小的女性 V 测量值明显更高（<20 岁 vs. 从未：β=26.88；95%CI，3.18-50.58；20-24 岁 vs. 从未：β=20.23；95%CI，-4.24-44.71；25-29 岁 vs. 从未：β=2.61；95%CI-29.00-34.23；≥30 岁 vs. 从未：β=0.28；95%CI，-34.16-34.72，p=0.03）。
我们的研究结果表明，OC 首次使用的年龄越早，V 值越大。
这些发现可能有助于指导 OC 起始年龄的决策。
