Women's College Research Institute, Women's College Hospital, 76 Grenville St., 6th Floor, Toronto, ON, Canada.
Department of Nutritional Sciences, University of Toronto, Toronto, ON, Canada.
BMC Cancer. 2019 Jun 26;19(1):631. doi: 10.1186/s12885-019-5855-2.
Mammographic density is one of the strongest risk factors for breast cancer. In the general population, mammographic density can be modified by various exposures; whether this is true for women a strong family history is not known. Thus, we evaluated the association between reproductive, hormonal, and lifestyle risk factors and mammographic density among women with a strong family history of breast cancer but no BRCA1 or BRCA2 mutation.
We included 97 premenopausal and 59 postmenopausal women (age range: 27-68 years). Risk factor data was extracted from the research questionnaire closest in time to the mammogram performed nearest to enrollment. The Cumulus software was used to measure percent density, dense area, and non-dense area for each mammogram. Multivariate generalized linear models were used to evaluate the relationships between breast cancer risk factors and measures of mammographic density, adjusting for relevant covariates.
Among premenopausal women, those who had two live births had a mean percent density of 28.8% vs. 41.6% among women who had one live birth (P=0.04). Women with a high body weight had a lower mean percent density compared to women with a low body weight among premenopausal (17.6% vs. 33.2%; P=0.0006) and postmenopausal women (8.7% vs. 14.7%; P=0.04). Among premenopausal women, those who smoked for 14 years or longer had a lower mean dense area compared to women who smoked for a shorter duration (25.3cm vs. 53.1cm; P=0.002). Among postmenopausal women, former smokers had a higher mean percent density (19.5% vs. 10.8%; P=0.003) and dense area (26.9% vs. 16.4%; P=0.01) compared to never smokers. After applying the Bonferroni correction, the association between body weight and percent density among premenopausal women remained statistically significant.
In this cohort of women with a strong family history of breast cancer, body weight was associated with mammographic density. These findings suggest that mammographic density may explain the underlying relationship between some of these risk factors and breast cancer risk, and lend support for the inclusion of mammographic density into risk prediction models.
乳腺密度是乳腺癌的最强危险因素之一。在一般人群中，乳腺密度可以通过各种暴露因素改变；对于有强烈乳腺癌家族史的女性，这种情况是否如此尚不清楚。因此，我们评估了生殖、激素和生活方式危险因素与无 BRCA1 或 BRCA2 突变的乳腺癌家族史强的女性的乳腺密度之间的关联。
我们纳入了 97 名绝经前和 59 名绝经后女性（年龄范围：27-68 岁）。风险因素数据从与最近接受的乳房 X 光检查最接近的研究问卷中提取。使用 Cumulus 软件测量每个乳房 X 光片的百分比密度、致密区和非致密区。使用多变量广义线性模型评估乳腺癌危险因素与乳腺密度测量值之间的关系，同时调整相关协变量。
在绝经前女性中，生育两次的女性的平均百分比密度为 28.8%，而生育一次的女性为 41.6%（P=0.04）。与体重较低的女性相比，体重较高的绝经前（17.6%比 33.2%；P=0.0006）和绝经后女性（8.7%比 14.7%；P=0.04）的平均百分比密度较低。在绝经前女性中，吸烟 14 年或以上的女性的平均致密区面积低于吸烟时间较短的女性（25.3cm 比 53.1cm；P=0.002）。在绝经后女性中，与从不吸烟者相比，以前吸烟者的平均百分比密度（19.5%比 10.8%；P=0.003）和致密区面积（26.9%比 16.4%；P=0.01）更高。在应用 Bonferroni 校正后，绝经前女性的体重与百分比密度之间的关联仍具有统计学意义。
在这个有强烈乳腺癌家族史的女性队列中，体重与乳腺密度有关。这些发现表明，乳腺密度可能解释了这些危险因素与乳腺癌风险之间的潜在关系，并支持将乳腺密度纳入风险预测模型。
