Mediterranean diet and breast density in the Minnesota Breast Cancer Family Study

Dietary Patterns, Dietary Interventions, and Mammographic Breast Density: A Systematic Literature Review

BACKGROUND

Breast cancer (BC) is the most common and deadliest malignancy among women. High mammographic breast density (MBD) is an established modifiable risk marker for BC, and it is of interest, for prevention purposes, to consider lifestyle factors that may modulate both MBD and BC risk. Here, we conducted a systematic review of the most up-to-date evidence on the association between diet as a whole and MBD.

METHODS

We considered as eligible for inclusion in our review (PROSPERO registration code CRD42022335289) the studies published until 31 December 2021, that reported on the association between a priori or a posteriori dietary patterns (in observational studies) or dietary interventions (in randomized controlled trials) and MBD.

RESULTS

In total, twelve studies were included. MBD tended to be inversely associated with adherence to dietary patterns characterized by high consumption of plant-based foods and low in meat, animal fats, and alcohol, defined both a priori (e.g., Mediterranean diet and WCRF/AICR guidelines) or a posteriori (e.g., "fruit-vegetable-cereal" and "salad-sauce-pasta/grains" patterns). Findings from intervention studies were in fair agreement with those from observational studies.

CONCLUSIONS

While further studies are needed, we found suggestive evidence that the adoption of a healthy diet is associated with lower MBD.

Breast Density: Current Knowledge, Assessment Methods, and Clinical Implications

Breast density is an accepted independent risk factor for the future development of breast cancer, and greater breast density has the potential to mask malignancies on mammography, thus lowering the sensitivity of screening mammography. The risk associated with dense breast tissue has been shown to be modifiable with changes in breast density. Numerous studies have sought to identify factors that influence breast density, including age, genetic, racial/ethnic, prepubertal, adolescent, lifestyle, environmental, hormonal, and reproductive history factors. Qualitative, semiquantitative, and quantitative methods of breast density assessment have been developed, but to date there is no consensus assessment method or reference standard for breast density. Breast density has been incorporated into breast cancer risk models, and there is growing consciousness of the clinical implications of dense breast tissue in both the medical community and public arena. Efforts to improve breast cancer screening sensitivity for women with dense breasts have led to increased attention to supplemental screening methods in recent years, prompting the American College of Radiology to publish Appropriateness Criteria for supplemental screening based on breast density.

Sugar-sweetened beverage consumption and breast composition in a longitudinal study of Chilean girls

Background

Frequent sugar-sweetened beverage (SSB) intake has been associated with indirect markers of breast cancer risk, such as weight gain in adolescents and early menarche. How SSB intake relates to breast composition in adolescent girls has not been explored.

Methods

We evaluated the association between prospective intake of SSB and breast density in a cohort of 374 adolescent girls participating in the Growth and Obesity Cohort Study in Santiago, Chile. Multivariable linear regression models were used to analyze the association between average daily SSB intake quartiles and breast composition (absolute fibroglandular volume [aFGV], percent fibroglandular volume [%FGV], total breast volume [tBV]). Models were adjusted for potential confounding by BMI Z-score, age, daily energy intake (g/day), maternal education, hours of daily television watching after school, dairy intake (g/day), meat intake (g/day), waist circumference, and menarche. To examine the sensitivity of the association to the number of dietary recalls for each girl, analyses were further stratified by girls with one dietary recall and girls with > one dietary recall.

Results

A total of 881 dietary recalls were available for 374 girls prior to the breast density assessment. More than 60% of the cohort had > one dietary recall available. In multivariable analyses, we found no association between SSB intake quartile and aFGV (Q2 vs Q1 β: − 5.4, 95% CI − 15.1, 4.4; Q3 vs Q1 β: 1.3, 95% CI − 8.6, 11.3; Q4 vs Q1 β: 3.0, 95% CI − 7.1, 13). No associations were noted for %FGV and tBV. Among girls with at least one dietary recall, we found no significant associations between SSB intake quartiles and %FGV, aFGV, or tBV.

Conclusion

Overall, we observed no evidence that SSB intake was associated with breast density in adolescent Chilean girls.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13058-021-01495-8.

The epidemiologic factors associated with breast density: A review

In recent years, some studies have evaluated the epidemiologic factors associated with breast density. However, the variant and inconsistent results exist. In addition, breast density has been proved to be a significant risk factor associated with breast cancer. Our review summarized the published studies and emphasized the crucial factors including epidemiological factors associated with breast density. In addition, we also discussed the potential reasons for the discrepant results with risk factors. To decrease the incidence and mortality rates for breast cancer, in clinical practice, breast density should be included for clinical risk models in addition to epidemiological factors, and physicians should get more concentrate on those women with risk factors and provide risk-based breast cancer screening regimens.

Family history of breast cancer is associated with elevated risk of prostate cancer: evidence for shared genetic risks

INTRODUCTION

Although breast and prostate cancers arise in different organs and are more frequent in the opposite sex, multiple studies have reported an association between their family history. Analysis of single nucleotide polymorphism data, based on distant relatives, has revealed a small positive genetic correlation between these cancers explained by common variants. The estimate of genetic correlation based on close relatives reveals the extent to which shared genetic risks are explained by both common and rare variants. This estimate is unknown for breast and prostate cancer.

METHOD

We estimated the relative risks, heritability, and genetic correlation of breast cancer and prostate cancer, based on the Minnesota Breast and Prostate Cancer Study, a family study of 141 families ascertained for breast cancer.

RESULTS

Heritability of breast cancer was 0.34 (95% credible interval: 0.23-0.49) and 0.65 (95% credible interval: 0.36-0.97) for prostate cancer, and the genetic correlation was 0.23. In terms of odds ratios, these values correspond to a 1.3 times higher odds of breast cancer among probands, given that the brother has prostate cancer.

CONCLUSION

This study shows the inherent relation between prostate cancer and breast cancer; an incident of one in a family increases the risk of developing the other. The large difference between estimates of genetic correlation from distant and close relatives, if replicated, suggests that rare variants contribute to the shared genetic risk of breast and prostate cancer. However, the difference could steam from genotype-by-family effects shared between the two types of cancers.

Adolescent and early adulthood inflammation-associated dietary patterns in relation to premenopausal mammographic density

BACKGROUND

Adolescence and early adulthood has been identified as a critical time window for establishing breast cancer risk. Mammographic density is an independent risk factor for breast cancer that may be influenced by diet, but there has been limited research conducted on the impact of diet on mammographic density. Thus, we sought to examine the association between adolescent and early adulthood inflammatory dietary patterns, which have previously been associated with breast cancer risk, and premenopausal mammographic density among women in the Nurses' Health Study II (NHSII).

METHODS

This study included control participants with premenopausal mammograms from an existing breast cancer case-control study nested within the NHSII who completed a Food Frequency Questionnaire in 1998 about their diet during high school (HS-FFQ) (n = 685) and/or a Food Frequency Questionnaire in 1991 (Adult-FFQ) when they were 27-44 years old (n = 1068). Digitized analog film mammograms were used to calculate the percent density, absolute dense, and non-dense areas. Generalized linear models were fit to evaluate the associations of a pro-inflammatory dietary pattern and the Alternative Healthy Eating Index (AHEI, an anti-inflammatory dietary pattern) with each breast density measure.

RESULTS

Significant associations were observed between an adolescent pro-inflammatory dietary pattern and mammographic density in some age-adjusted models; however, these associations did not remain after adjustment for BMI and other breast cancer risk factors. No associations were observed with the pro-inflammatory pattern or with the AHEI pattern in adolescence or early adulthood in fully adjusted models.

CONCLUSIONS

To our knowledge, this is the first study to evaluate the dietary patterns during adolescence and early adulthood in relation to mammographic density phenotypes. Our findings do not support an association between adolescent and early adulthood diet and breast density in mid-adulthood that is independent of BMI or other breast cancer risk factors.

Dietary energy density is positively associated with breast density among young women

BACKGROUND

Breast density is an established predictor of breast cancer risk, and there is considerable interest in associations of modifiable lifestyle factors, such as diet, with breast density.

OBJECTIVE

To determine whether dietary energy density (ED) is associated with percent dense breast volume (%DBV) and absolute dense breast volume (ADBV) in young women.

DESIGN

A cross-sectional analysis was conducted with women who participated in the Dietary Intervention Study in Children Follow-Up Study. %DBV and ADBV were measured by magnetic resonance imaging. Diet was assessed by three 24-hour recalls. Dietary ED (kilocalories/gram) was calculated using three methods: food only, food and caloric beverages, and food and all beverages.

PARTICIPANTS/SETTING

One hundred seventy-two women (aged 25 to 29 years) who were enrolled in the Dietary Intervention Study in Children Follow-Up Study. Participants who reported breast augmentation or reduction surgery or were pregnant or lactating within 3 months before breast density assessment were excluded.

MAIN OUTCOME MEASURES

ADBV and %DBV.

STATISTICAL ANALYSES PERFORMED

Multivariable linear mixed effects models were used. Final models were adjusted for race, smoking status, education, parity, duration of sex hormone use, whole body percent fat, childhood body mass index z score, and energy from beverages.

RESULTS

After adjustment, each 1 kcal/g unit increase in food-only ED was associated with a 25.9% (95% CI 6.2% to 56.8%) increase in %DBV (P=0.01). Childhood body mass index z score modified the association between food-only ED and %DBV such that a significant positive association was observed only in women who were heavier as children. Food-only ED was not associated with ADBV in all women, but a borderline significant positive association was observed in women who had higher childhood body mass index z scores.

CONCLUSIONS

This is the first report to suggest a potential role for dietary ED in breast density; the effects of long-term exposure to high-ED diets on breast cancer risk remain unknown.

Calorie intake, olive oil consumption and mammographic density among Spanish women

High mammographic density (MD) is one of the main risk factors for development of breast cancer. To date, however, relatively few studies have evaluated the association between MD and diet. In this cross-sectional study, we assessed the association between MD (measured using Boyd's semiquantitative scale with five categories: <10%, 10–25%, 25–50%, 50–75% and >75%) and diet (measured using a food frequency questionnaire validated in a Spanish population) among 3,548 peri- and postmenopausal women drawn from seven breast cancer screening programs in Spain. Multivariate ordinal logistic regression models, adjusted for age, body mass index (BMI), energy intake and protein consumption as well as other confounders, showed an association between greater calorie intake and greater MD [odds ratio (OR) = 1.23; 95% confidence interval (CI) = 1.10-1.38, for every increase of 500 cal/day], yet high consumption of olive oil was nevertheless found to reduce the prevalence of high MD (OR = 0.86;95% CI = 0.76-0.96, for every increase of 22 g/day in olive oil consumption); and, while greater intake of whole milk was likewise associated with higher MD (OR = 1.10; 95%CI 1.00-1.20, for every increase of 200 g/day), higher consumption of protein (OR = 0.89; 95% CI 0.80-1.00, for every increase of 30 g/day) and white meat (p for trend 0.041) was found to be inversely associated with MD. Our study, the largest to date to assess the association between diet and MD, suggests that MD is associated with modifiable dietary factors, such as calorie intake and olive oil consumption. These foods could thus modulate the prevalence of high MD, and important risk marker for breast cancer.

Association of Mediterranean diet, dietary supplements and alcohol consumption with breast density among women in South Germany: a cross-sectional study

BACKGROUND

Effects of dietary factors, such as adherence to Mediterranean diet, multivitamin-multimineral supplements use and alcohol consumption on mammographic breast density, an important biomarker of breast cancer risk, are not sufficiently consistent to elaborate preventive recommendations. This study aims to investigate the association between current diet and mammographic density.

METHODS

We performed a cross-sectional study in 424 pre- and post-menopausal women aged 21 to 84 years. Current Mediterranean dietary pattern, multivitamin-multimineral supplements use, alcohol consumption and potential confounders were assessed with a self-administered questionnaire in the University Hospital Ulm (2007-2008). Radiologists evaluated mammographic density according to the American College of Radiology (ACR) classification, which was summarized in low = ACR1/2 and high = ACR3/4 mammographic density. Logistic regression models were used to assess the association between current diet and mammographic density.

RESULTS

Adherance to Mediterranean dietary pattern was inversely associated with mammographic density in the models adjusted for age and BMI (per 1 unit increase of score OR 0.95; 95%CI 0.90-0.997). Current use of multivitamin-multimineral supplements was also inversely associated with mammographic density (OR 0.53; 95%CI 0.34-0.83). Further adjustment revealed similar point estimates but the associations were no longer statistically significant. Compared to non-drinkers, excessive alcohol consumption (<10 g/d) was positively associated with mammographic density (OR 1.47; 95%CI 0.82-2.63).

CONCLUSIONS

Our results show that dietary factors are associated with mammographic density. Adherence to Mediterranean diet and current use of multivitamin-multimineral supplements could be inversely associated with mammographic density and may suggest a protective effect against breast cancer, whereas high alcohol consumption was associated with increased mammographic density.

Diet across the Lifespan and the Association with Breast Density in Adulthood

Studies have shown inconsistent results regarding the association between dietary factors across the lifespan and breast density and breast cancer in women. Breast density is a strong risk factor for breast cancer, and the mechanism through which it influences cancer risk remains unclear. Breast density has been shown to be modifiable, potentially through dietary modifications. The goal of this paper is to summarize the current studies on diet and diet-related factors across all ages, determine which dietary factors show the strongest association with breast density, the most critical age of exposure, and identify future directions. We identified 28 studies, many of which are cross-sectional, and found that the strongest associations are among vitamin D, calcium, dietary fat, and alcohol in premenopausal women. Longitudinal studies with repeated dietary measures as well as the examination of overall diet over time are needed to confirm these findings.

Phytochemical potential of Eruca sativa for inhibition of melanoma tumor growth

Solvent extracts from the aerial and root parts and seed oil from E. sativa (rocket salad) were assayed for anticancer activity against melanoma cells. The seed oil (isothiocyanates rich) significantly (p<0.01) reduced the tumor growth comparable to the control. Remarkably, the seed oil inhibited melanoma growth and angiogenesis in mice without any major toxicity. The findings qualify seed oil for further investigations in the real of cancer prevention and treatment.

Dietary patterns and breast cancer risk: a systematic review and meta-analysis

BACKGROUND

Dietary patterns, which represent whole-diet and possible food and nutrient interactions, have been linked to the risk of various cancers. However, the associations of these dietary patterns with breast cancer remain unclear.

OBJECTIVE

We critically appraised the literature and conducted meta-analyses to pool the results of studies to clarify the relation between dietary patterns and breast cancer risk.

DESIGN

MEDLINE and EMBASE were searched for relevant articles that identified common dietary patterns published up to November 2009. Multivariable-adjusted odds ratios (ORs) comparing highest and lowest categories of dietary pattern scores and multivariable-adjusted ORs for a 20th-percentile increase in dietary pattern scores were combined by using random-effects meta-analyses.

RESULTS

Case-control and cohort studies were retrieved that identified prudent/healthy (n = 18), Western/unhealthy (n = 17), and drinker (n = 4) dietary patterns. There was evidence of a decrease in the risk of breast cancer in the highest compared with the lowest categories of prudent/healthy dietary patterns (OR = 0.89; 95% CI: 0.82, 0.99; P = 0.02) in all studies and in pooled cohort studies alone. An increase in the risk of breast cancer was shown for the highest compared with the lowest categories of a drinker dietary pattern (OR = 1.21; 95% CI: 1.04, 1.41; P = 0.01). There was no evidence of a difference in the risk of breast cancer between the highest and the lowest categories of Western/unhealthy dietary patterns (OR = 1.09; 95% CI: 0.98, 1.22; P = 0.12).

CONCLUSION

The results of this systematic review and meta-analysis indicate that some dietary patterns may be associated with breast cancer risk.

Dietary patterns, risk and prognosis of breast cancer

Survival in women diagnosed with early-stage, invasive breast cancer has improved dramatically in the past 10–15 years. This is largely due to the use of pharmacological therapies targeting a reduction in estrogen action and exposure. Women diagnosed with breast cancer often alter their eating behavior towards healthier food choices in an attempt to improve their survival and their overall health and well being. Mounting interest in the role of diet to modify breast cancer survival and/or comorbidity and mortality has led researchers to evaluate the effects of differential dietary patterns on this disease. Current findings suggest a possible, but inconsistent, benefit of a prudent, vegetable-rich, low-fat/high-vegetable eating pattern on disease-free survival, but the results to date are limited by strong treatment effectiveness and low overall recurrence rates. It is more likely this prudent eating pattern will improve non-breast cancer mortality (e.g., cardiovascular disease) compared with a Western dietary pattern. Efforts to educate women diagnosed with breast cancer to consume a diet lower in total and saturated fat, higher in vegetables and fiber, and which results in mild to modest weight loss among overweight/obese women is sensible in light of the high survivability of breast cancer and need to direct attention to comorbidities that likely increase as a consequence of treatment and treatment-related weight gain and sedentary behavior. Additional research is needed to address the importance of diet in the breast cancer patient, particularly in relation to the effect of select dietary patterns on factors that influence individual recurrence risk (e.g., hormone levels, drug metabolism and oxidative stress), as well as factors that influence non-breast cancer morbidity risk and causes of death in the survivor population.