Percent mammographic density (PMD) is a strong breast cancer risk factor, however, other mammographic features, such as V, the standard deviation (SD) of pixel intensity, may be associated with risk. We assessed whether PMD, automated PMD (APD), and V, yielded independent associations with breast cancer risk. We included 1900 breast cancer cases and 3921 matched controls from the Nurses’ Health Study (NHS) and the NHSII. Using digitized film mammograms, we estimated PMD using a computer-assisted thresholding technique. APD and V were determined using an automated computer algorithm. We used logistic regression to generate odds ratios (ORs) and 95% confidence intervals (CIs). Median time from mammogram to diagnosis was 4.1 years (interquartile range: 1.6–6.8 years). PMD (OR _{per SD}:1.52, 95% CI: 1.42, 1.63), APD (OR _{per SD}:1.32, 95% CI: 1.24, 1.41), and V (OR _{per SD}:1.32, 95% CI: 1.24, 1.40) were positively associated with breast cancer risk. Associations for APD were attenuated but remained statistically significant after mutual adjustment for PMD or V. Women in the highest quartile of both APD and V (OR _{vs Q1/Q1}: 2.49, 95% CI: 2.02, 3.06), or PMD and V (OR _{vs Q1/Q1}: 3.57, 95% CI: 2.79, 4.58) had increased breast cancer risk. An automated method of PMD assessment is feasible and yields similar, but somewhat weaker, estimates to a manual measure. PMD, APD and V are each independently, positively associated with breast cancer risk. Women with dense breasts and greater texture variation are at the highest relative risk of breast cancer.

乳房 X 光密度百分比 (PMD) 是乳腺癌的一个重要风险因素，然而，其他乳房 X 光检查特征，例如 V、像素强度的标准差 (SD)，可能与风险相关。我们评估了 PMD、自动 PMD (APD) 和 V 是否与乳腺癌风险产生独立关联。我们纳入了来自护士健康研究 (NHS) 和 NHSII 的 1900 例乳腺癌病例和 3921 例匹配对照。使用数字化胶片乳房 X 光照片，我们使用计算机辅助阈值技术估计 PMD。 APD 和 V 使用自动计算机算法确定。我们使用逻辑回归来生成比值比 (OR) 和 95% 置信区间 (CI)。从乳房 X 光检查到诊断的中位时间为 4.1 年（四分位数范围：1.6-6.8 年）。 PMD（OR_{每 SD} ：1.52，95% CI：1.42、1.63）、APD（OR_{每 SD} ：1.32、95% CI：1.24、1.41）和 V（OR_{每 SD} ：1.32、95% CI：1.24、1.40 ）与乳腺癌风险呈正相关。在对 PMD 或 V 进行相互调整后，APD 的相关性减弱，但仍具有统计学意义。女性处于 APD 和 V 的最高四分位数（OR_{与 Q1/Q1} ：2.49，95% CI：2.02、3.06），或 PMD 和 V（ OR _{vs Q1/Q1} ：3.57，95% CI：2.79，4.58）乳腺癌风险增加。 PMD 评估的自动化方法是可行的，并且产生与手动测量相似但稍弱的估计。 PMD、APD 和 V 各自独立地与乳腺癌风险呈正相关。乳房致密且质地变化较大的女性患乳腺癌的相对风险最高。