Department of Environmental Epidemiology, Nofer Institute of Occupational Medicine, Lodz, Poland.
Department of Biological and Environmental Monitoring, Nofer Institute of Occupational Medicine, Lodz, Poland.
PLoS One. 2020 May 20;15(5):e0233369. doi: 10.1371/journal.pone.0233369. eCollection 2020.
Cadmium (Cd) is a heavy metal, which is widespread in the environment and has been hypothesized to be a metalloestrogen and a breast cancer risk factor. Mammographic density (MD) reflects the composition of the breast and was proposed to be used as a surrogate marker for breast cancer. The aim of our study was to investigate association between cadmium concentration in urine and mammographic density.
A cross-sectional study included 517 women aged 40-60 years who underwent screening mammography in Łódź, Poland. Data were collected through personal interviews and anthropometric measurements. Spot morning urine samples were obtained. The examination of the breasts included both craniocaudal and mediolateral oblique views. Raw data ("for processing") generated by the digital mammography system were analysed using Volpara Imaging Software, The volumetric breast density(%) and fibrograndular tissue volume(cm3) were determined. Cadmium concentration in urine was analysed using the standard ICP-MS method.
After adjusting for key confounders including age, BMI, family breast cancer, mammographic device, season of the year of mammography, and age at menarche, an inverse association of Cd and volumetric breast density was found, which was attenuated after further adjustment for smoking. Associations of Cd with dense volume were null.
These findings suggest that Cd is not positively associated with breast density, a strong marker of breast cancer risk, when examined in a cross-sectional fashion.
镉（Cd）是一种重金属，广泛存在于环境中，据推测它是一种金属雌激素和乳腺癌的危险因素。乳腺密度（MD）反映了乳房的成分，被提议作为乳腺癌的替代标志物。我们的研究目的是调查尿液中镉浓度与乳腺密度之间的关联。
这是一项横断面研究，包括 517 名年龄在 40-60 岁之间的波兰罗兹妇女，她们接受了乳房 X 光筛查。数据通过个人访谈和人体测量收集。采集早晨的尿液样本。乳房检查包括头尾位和内外斜位。数字乳房 X 光摄影系统生成的原始数据（“待处理”）使用 Volpara 成像软件进行分析，确定体积乳腺密度（%）和纤维腺体组织体积（cm3）。使用标准的 ICP-MS 方法分析尿液中的镉浓度。
在调整了关键混杂因素（包括年龄、BMI、家族乳腺癌、乳房 X 光设备、乳房 X 光摄影的季节和初潮年龄）后，发现 Cd 与体积乳腺密度呈负相关，进一步调整吸烟因素后，这种关联减弱。 Cd 与致密体积之间的关联为零。
这些发现表明，在横断面研究中，Cd 与乳腺密度（乳腺癌风险的一个强标志物）之间没有正相关关系。
