The Association Between Mammographic Breast Density and Bone Mineral Density in the Study of Women's Health Across the Nation

Understanding mammographic breast density profile in China: A Sino-Australian comparative study of breast density using real-world data from cancer screening programs

AIM

This study aims at understanding mammographic density profile in China by comparing the density between women in China and Australia.

METHODS

Data of 3250 women aged 45-69 were obtained from the Cancer Screening Program in Urban China and data of 1384 Australian counterparts at same age range were gathered from the Lifepool project. Demographic and reproductive details and mammograms for each cohort were collected. Mammographic density was assessed using AutoDensity, and two metrics, percentage density (PD) and dense area (DA), were applied. T-tests were used to compare the means of mammographic density between two populations of all, premenopausal, and postmenopausal women. Two-way ANOVA was conducted to examine interactions of population (Chinese/Australian) and each variable of interest upon mammographic density.

RESULTS

Chinese women had 9.61%, 8.20%, and 9.28% higher PD than their Australian counterparts in all, premenopausal, and postmenopausal women, respectively (all p < 0.001). The mean differences in DA between two population were 1.81 cm² (p < 0.001), 0.55 cm² (p = 0.472), and 1.76 cm² (p = 0.003) for all, premenopausal, and postmenopausal women, respectively. There were significant interactions between population and age (F[4, 4624] = 4.12, p = 0.003), BMI (F[2, 4628] = 3.92, p = 0.020), age at first birth (F[1, 4250] = 11.69, p < 0.001), breastfeeding history (F[1, 4479] = 17.79, p < 0.001), and breastfeeding duration (F[1, 3526] = 66.90, p < 0.001) upon PD. Interaction was only found for breastfeeding history (F[1, 4479] = 4.79, p = 0.029) and breastfeeding duration (F[1, 3526] = 17.72, p < 0.001) for DA.

CONCLUSIONS

Both PD and DA were found to be higher in Chinese women compared to Australian women. The density difference by menopause status was shown and breastfeeding history affected breast density differently in both populations.

Is There an Association Between Bone Mineral Density and Mammographic Density? A Systematic Review

INTRODUCTION

Both bone mineral density (BMD) and breast density are related to reproductive hormone levels. This suggests that BMD and breast density could be meaningfully associated, and serve as surrogate markers for breast cancer risk. However, few studies have investigated the association of BMD with percent mammographic density, making it difficult to draw meaningful conclusions.

MATERIALS AND METHODS

We conducted a systematic review of studies published in electronic databases till April 2016 using the following search terms: "bone density," "bone mineral density," "mammographic breast density," "breast density," and "mammographic density." We identified 203 articles, of which 8 met the inclusion criteria for this review.

RESULTS

BMD does not appear to be associated with percent mammographic density. BMD at the spine was weakly positively associated with percent mammographic density among postmenopausal women who were not hormone users, while BMD at the hip and legs was positively associated with percent mammographic density among premenopausal women. On the other hand, one study reported an inverse association of BMD at the spine and hip with percent mammographic density among perimenopausal women.

CONCLUSION

In this review, we found no evidence of an association between BMD and percent mammographic density.

Bone mineral density and mammographic density in Mexican women

BACKGROUND

Bone mineral density (BMD) is a putative marker for lifetime exposure to estrogen. Studies that have explored whether BMD is a determinant of mammographic density (MD) have observed inconsistent results. Therefore,we examined this potential association in a sample of women (n = 1,516) from the clinical sub-cohort in the Mexican teachers’ cohort (n = 115,315).

METHODS

We used multivariable linear regression to assess the association between quartiles of BMD and percent MD, as well as total dense and non-dense area of the breast, stratified by menopausal status. We also examined the associations by body mass index (BMI) (< 30 kg/m(2), ≥ 30 kg/m(2)).

RESULTS

Overall, there was no association between BMD and MD among premenopausal women. However, when we stratified by BMI, there was a modest inverse association between BMD and percent MD (difference between extreme quartiles = -2.8, 95 % CI -5.9, 0.27, p trend = 0.04) among women with BMI < 30 kg/m(2), but a positive association among obese women (comparable difference = 5.1, 95 % CI 0.02, 10.1, p trend = 0.03;p interaction < 0.01). Among postmenopausal women, BMD and percent MD were positively associated after adjustment for BMI (p trend < 0.01). Postmenopausal women in the highest two quartiles of BMD had 4–5 % point higher percent MD compared to women in the lowest quartile. The association did not differ by BMI in postmenopausal women (p interaction = 0.76).

CONCLUSION

Among obese premenopausal women as well as postmenopausal women, BMD was positively associated with percent MD. Among leaner premenopausal women, BMD and percent MD were modestly inversely associated. These findings support the hypothesis that cumulative exposure to estrogen (as measured by BMD) may influence MD.

Mammogram retrieval on similar mass lesions

Enormous numbers of digital mammograms have been produced in hospitals and breast screening centers. To exploit those valuable resources in aiding diagnoses and research, content-based mammogram retrieval systems are required to effectively access the mammogram databases. This paper presents a content-based mammogram retrieval system, which allows medical professionals to seek mass lesions that are pathologically similar to a given example. In this retrieval system, shape and margin features of mass lesions are extracted to represent the characteristics of mammographic lesions. To compare the similarity between the query example and any lesion within the databases, this study proposes a similarity measure scheme which involves the hierarchical arrangement of mammographic features and a weighting distance measure. This makes similarity measure of the retrieval system consistent with the way radiologists observe mass lesions. This study used the DDSM dataset to evaluate the effectiveness of the extracted shape feature and margin feature, respectively. Experimental results demonstrate that, when Zernike moments are used, round-shape masses are the most discriminative among four types of shape; the circumscribed-margin masses can be effectively discriminated among the four types of margins. Moreover, the result also shows that, when retrieving round-shape and circumscribed margin masses, this retrieval system can achieve the highest precision among all mass lesion types.

The relationship between bone mineral density and mammographic density in Korean women: the Healthy Twin study

Mammographic density is one of the strong risk factors for breast cancer. A potential mechanism for this association is that cumulative exposure to mammographic density may reflect cumulative exposure to hormones that stimulate cell division in breast stroma and epithelium, which may have corresponding effects on breast cancer development. Bone mineral density (BMD), a marker of lifetime estrogen exposure, has been found to be associated with breast cancer. We examined the association between BMD and mammographic density in a Korean population. Study subjects were 730 Korean women selected from the Healthy Twin study. BMD (g/cm(2)) was measured with dual-energy X-ray absorptiometry. Mammographic density was measured from digital mammograms using a computer-assisted thresholding method. Linear mixed model considering familial correlations and a wide range of covariates was used for analyses. Quantitative genetic analysis was completed using SOLAR. In premenopausal women, positive associations existed between absolute dense area and BMD at ribs, pelvis, and legs, and between percent dense area and BMD at pelvis and legs. However, in postmenopausal women, there was no association between BMD at any site and mammographic density measures. An evaluation of additive genetic cross-trait correlation showed that absolute dense area had a weak-positive additive genetic cross-trait correlation with BMD at ribs and spines after full adjustment of covariates. This finding suggests that the association between mammographic density and breast cancer could, at least in part, be attributable to an estrogen-related hormonal mechanism.

Alcohol, tobacco, and mammographic density: a population-based study

Mammographic density (MD), or the proportion of the breast with respect to its overall area that is composed of dense tissue, is a strong risk factor for breast cancer. Studies support a positive association of mammographic density and alcohol drinking. This was a cross-sectional multicenter study based on 3584 women, aged 45-68 years, recruited from seven screening centers within the Spanish breast cancer screening program network. The association between MD, alcohol consumption and tobacco use was evaluated by using ordinal logistic models with random center-specific intercepts. We found a weak positive association between current alcohol intake and higher MD, with current alcohol consumption increasing the odds of high MD by 13% (OR = 1.13; 95% CI 0.99-1.28) and high daily grams of alcohol being positively associated with increased MD (P for trend = 0.045). There were no statistically significant differences in MD between smokers and non-smokers. Nevertheless, increased number of daily cigarettes and increased number of accumulated lifetime cigarettes were negatively associated with high MD (P for trend 0.017 and 0.021). The effect of alcohol on MD was modified by menopausal status and tobacco smoking: whereas, alcohol consumption and daily grams of alcohol were positively associated with higher MD in postmenopausal women and in women who were not currently smoking, alcohol consumption had no effect on MD in premenopausal women and current smokers. Our results support an association between recent alcohol consumption and high MD, characterized by a modest increase in risk at low levels of current consumption and a decrease in risk among heavier drinkers. Our study also shows how the effects of alcohol in the breast can be modified by other factors, such as smoking.

Breast density changes associated with postmenopausal hormone therapy: post hoc radiologist- and computer-based analyses

OBJECTIVE

The aim of this study was to assess the impact of oral hormone therapy (HT) on breast density in postmenopausal women and to compare the use of computer-based automated approaches for the assessment of breast density with reference to traditional methods.

METHODS

Low-dose oral estrogen (1 mg) continuously combined with drospirenone (2 mg) was administered to postmenopausal women for up to 2 years (26 treatment cycles, 28 d/cycle) in a randomized, placebo-controlled trial. This post hoc analysis assessed the changes in breast density measured from digitized images by two radiologist-based approaches (Breast Imaging Reporting and Data System score and interactive threshold) and one computer-based technique (heterogeneity examination of radiographs). Correlations of temporal changes in breast density with changes in serum estradiol levels, biochemical markers of bone metabolism, and bone mineral density at the spine and femur were also assessed.

RESULTS

Breast density assessed by the radiologist-based approaches increased significantly from baseline in the HT group (P < 0.01), with significant divergence from placebo at 2 years (P < 0.01). Heterogeneity examination of radiograph score by computer-based technique was unchanged in the HT group and decreased significantly with placebo (P < 0.001) to produce a significant group divergence (P < 0.05). Changes in mammographic markers by radiologist- and computer-based approaches correlated with each other in the HT group (P < 0.01) but not in the placebo group.

CONCLUSIONS

HT for 2 years in postmenopausal women significantly increased radiologist-assessed breast density compared with placebo, in addition to significant changes in estrogen levels, markers of bone metabolism, and bone mineral density. Computer-automated techniques may be comparable with and offer advantages over traditional methods.

Lean body mass, not estrogen or progesterone, predicts peak bone mineral density in premenopausal women

Estrogen and body fat content are important predictors of bone mineral density (BMD) in postmenopausal women, but their association with BMD in premenopausal women is less clear. Mounting evidence suggests that dietary fats can have detrimental effects on bone health. In a cross-sectional sample of healthy 30- to 40-y-old women (n = 242), we investigated the predictors of BMD at the hip and spine by multilevel multiple regression analyses. Predictor variables in the models included dietary intake of various fats, serum concentrations of sex steroids, blood chemistries and markers of metabolic syndrome, anthropometric variables, and ethnicity. Among these premenopausal women, lean body mass was the strongest independent predictor (P < 0.0001) and African-American ethnicity (P < 0.05) was another positive independent predictor of BMD at the hip and spine. Dietary fats were not independent predictors of BMD of hip and spine. Lean body mass and being African-American explained 33% of the variance in hip BMD. Lean body mass, African-American ethnicity, and serum concentrations of triglycerides (a negative predictor, P = 0.0001) explained 28% of the variance in spine BMD. In contrast, luteal phase serum concentrations of estradiol, progesterone, and testosterone were not predictors of BMD. It remains to be determined whether efforts to increase lean body mass in premenopausal women with normal levels of endogenous estrogen may be an effective preventive strategy to preserve bone health.

Bone mineral density at menopause does not predict breast cancer incidence

In this prospective study in 2,137 perimenopausal and early postmenopausal women who were followed over a 13.1-year period of time, we observed no association between bone mineral density measured at the beginning of menopause and the subsequent risk of breast cancer.

INTRODUCTION

This study aimed to investigate the relationship between BMD and the risk of breast cancer (BC) in young postmenopausal women.

METHODS

As part of a clinical research program, 2,137 women who were perimenopausal or within their 5 first postmenopausal years were scanned between 1988-1990 and reviewed on average 13.1 years after their initial examination. Ninety-eight incident BC cases were recorded throughout the follow-up.

RESULTS

Women with incident BC significantly differed from those who had never had BC with regard to age at menarche, age of birth of 1st child, familial history of BC and postmenopausal hormone therapy (PHT) use. There was no significant difference between the two groups for baseline DXA of the spine. There was a trend for BC cases for having lower femoral neck BMD compared to women without BC. However, women with low BMD were more likely to have taken PHT by the end of the study. In Cox multivariate analyses the relationship between BC risk and femoral neck BMD no longer existed.

CONCLUSIONS

There was no relationship between BMD measured within the first postmenopausal years and the risk of BC, which makes unlikely the possibility of using BMD as a predictor factor for BC in early postmenopausal women.