Mammographic density and ageing: A collaborative pooled analysis of cross-sectional data from 22 countries worldwide

Abstract

BackgroundMammographic density (MD) is one of the strongest breast cancer risk factors. Its age-related characteristics have been studied in women in western countries, but whether these associations apply to women worldwide is not known.Methods and findingsWe examined cross-sectional differences in MD by age and menopausal status in over 11,000 breast-cancer-free women aged 35–85 years, from 40 ethnicity- and location-specific population groups across 22 countries in the International Consortium on Mammographic Density (ICMD). MD was read centrally using a quantitative method (Cumulus) and its square-root metrics were analysed using meta-analysis of group-level estimates and linear regression models of pooled data, adjusted for body mass index, reproductive factors, mammogram view, image type, and reader. In all, 4,534 women were premenopausal, and 6,481 postmenopausal, at the time of mammography. A large age-adjusted difference in percent MD (PD) between post- and premenopausal women was apparent (–0.46 cm [95% CI: −0.53, −0.39]) and appeared greater in women with lower breast cancer risk profiles; variation across population groups due to heterogeneity (I2) was 16.5%. Among premenopausal women, the √PD difference per 10-year increase in age was −0.24 cm (95% CI: −0.34, −0.14; I2 = 30%), reflecting a compositional change (lower dense area and higher non-dense area, with no difference in breast area). In postmenopausal women, the corresponding difference in √PD (−0.38 cm [95% CI: −0.44, −0.33]; I2 = 30%) was additionally driven by increasing breast area. The study is limited by different mammography systems and its cross-sectional rather than longitudinal nature.ConclusionsDeclines in MD with increasing age are present premenopausally, continue postmenopausally, and are most pronounced over the menopausal transition. These effects were highly consistent across diverse groups of women worldwide, suggesting that they result from an intrinsic biological, likely hormonal, mechanism common to women. If cumulative breast density is a key determinant of breast cancer risk, younger ages may be the more critical periods for lifestyle modifications aimed at breast density and breast cancer risk reduction.

PAM50 and Risk of Recurrence Scores for Interval Breast Cancers

“…Multiple studies have shown high mammographic density to be associated with interval cancers(44–46), including our own findings herein. However, it is difficult to disentangle tumor biology and mammographic density because younger women have both higher density and more aggressive tumor characteristics(47,48). We were unable to consider the independent contributions of age, race, and mammographic density due to sample size.…”

SAR analysis of directive antenna on anatomically real breast phantoms for microwave holography

“…Figure shows the SAR analysis on the phantoms of different age group at randomly picked fixed distance and power corresponding to 5 mm and 1 mW, respectively. It is found that the change in SAR values is nonsymmetrical for different patients because there is no fixed defined pattern of variation in the breast tissue density and age of the patients, breast density may differ for two individuals of the same age group . The same is evident from the aforementioned figure, that the SAR values for different age groups vary independently, even though the distance of antenna and the microwave source power are fixed with the similar antenna placed in the vicinity of all breast models.…”

Using an automated measure of breast density to explore the association between ethnicity and mammographic density in Australian women

“…A range of approaches have been taken to examining this issue in terms of study design as well as the method(s) used to assess mammographic density . Some studies have reported, for example, that the characteristic associations seen between mammographic density and age (or menopausal status) are seen consistently across different ethnic groups or that mammographic density is not different in women of different ethnicities, especially when data are adjusted for BMI . The picture may also be influenced by which ethnicities are considered Asian, as the picture may be different for women from East and South Asia …”