Diet and breast cancer

Associations of Vitamins and Related Cofactor Metabolites with Mammographic Breast Density in Premenopausal Women

BACKGROUND

Identifying biological drivers of mammographic breast density (MBD), a strong risk factor for breast cancer, could provide insight into breast cancer etiology and prevention. Studies on dietary factors and MBD have yielded conflicting results. There are, however, very limited data on the associations of dietary biomarkers and MBD.

OBJECTIVE

We aimed to investigate the associations of vitamins and related cofactor metabolites with MBD in premenopausal women.

METHODS

We measured 37 vitamins and related cofactor metabolites in fasting plasma samples of 705 premenopausal women recruited during their annual screening mammogram at the Washington University School of Medicine, St. Louis, MO. Volpara was used to assess volumetric percent density (VPD), dense volume (DV), and nondense volume (NDV). We estimated the least square means of VPD, DV, and NDV across quartiles of each metabolite, as well as the regression coefficient of a metabolite in continuous scale from multiple covariate-adjusted linear regression. We corrected for multiple testing using the Benjamini-Hochberg procedure to control the false discover rate (FDR) at a 5% level.

RESULTS

Participants' mean VPD was 10.5%. Two vitamin A metabolites (β-cryptoxanthin and carotene diol 2) were positively associated, and one vitamin E metabolite (γ-tocopherol) was inversely associated with VPD. The mean VPD increased across quartiles of β-cryptoxanthin (Q1 = 7.2%, Q2 = 7.7%, Q3 = 8.4%%, Q4 = 9.2%; P-trend = 1.77E-05, FDR P value = 1.18E-03). There was a decrease in the mean VPD across quartiles of γ-tocopherol (Q1 = 9.4%, Q2 = 8.1%, Q3 = 8.0%, Q4 = 7.8%; P -trend = 4.01E-03, FDR P value = 0.04). Seven metabolites were associated with NDV: 3 vitamin E (γ-CEHC glucuronide, δ-CEHC, and γ-tocopherol) and 1 vitamin C (gulonate) were positively associated, whereas 2 vitamin A (carotene diol 2 and β-cryptoxanthin) and 1 vitamin C (threonate) were inversely associated with NDV. No metabolite was significantly associated with DV.

CONCLUSION

We report novel associations of vitamins and related cofactor metabolites with MBD in premenopausal women.

Logistic LASSO Regression for Dietary Intakes and Breast Cancer

A multitude of dietary factors from dietary fat to macro and micronutrients intakes have been associated with breast cancer, yet data are still equivocal. Therefore, utilizing data from the large, multi-year, cross-sectional National Health and Nutrition Examination Survey (NHANES), we applied a novel, modern statistical shrinkage technique, logistic least absolute shrinkage and selection operator (LASSO) regression, to examine the association between dietary intakes in women, ≥50 years, with self-reported breast cancer (n = 286) compared with women without self-reported breast cancer (1144) from the 1999–2010 NHANES cycle. Logistic LASSO regression was used to examine the relationship between twenty-nine variables, including dietary variables from food, as well as well-established/known breast cancer risk factors, and to subsequently identify the most relevant variables associated with self-reported breast cancer. We observed that as the penalty factor (λ) increased in the logistic LASSO regression, well-established breast cancer risk factors, including age (β = 0.83) and parity (β = −0.05) remained in the model. For dietary macro and micronutrient intakes, only vitamin B12 (β = 0.07) was positively associated with self-reported breast cancer. Caffeine (β = −0.01) and alcohol (β = 0.03) use also continued to remain in the model. These data suggest that a diet high in vitamin B12, as well as alcohol use may be associated with self-reported breast cancer. Nonetheless, additional prospective studies should apply more recent statistical techniques to dietary data and cancer outcomes to replicate and confirm the present findings.

Antiproliferative Activity of Ursolic Acid in MDA-MB-231 Human Breast Cancer Cells through Nrf2 Pathway Regulation

The potential mechanisms of action of ursolic acid (UA) in regulating cell proliferation in MDA-MB-231 human breast cancer cells through Nrf2 pathway were investigated. UA significantly inhibited the proliferation of MDA-MB-231 cells at a dose ≥10 μM in a dose-dependent manner, and no cytotoxicity was observed at concentrations below 29.87 ± 2.60 μM. The expressions of Nrf2 and p-Nrf2, in whole cell and nucleus, and NQO1 were inhibited by UA treatment, whereas the Keap1 expression was upregulated. No significant difference was observed in the Nrf2 mRNA levels, indicating that UA reduced Nrf2 expression not through mRNA but through a post-translational mechanism. Additionally, EGF-induced p-Nrf2 and its downstream NQO1 and SOD1 enzymes were abolished by UA. However, EGF or p-EGFR had no effect on the expressions of Keap1. These results suggested that the proliferative inhibitory effect of UA might be partially through downregulating Nrf2 via the Keap1/Nrf2 pathway and EGFR/Nrf2 pathway in MDA-MB-231 cells.

Dietary Inflammatory Index and Risk of Breast Cancer Based on Hormone Receptor Status: A Case-Control Study in Korea

Breast cancer is the most common cancer in women globally, and the risk of developing breast cancer is associated with inflammation. The present study aimed to examine the association between the Dietary Inflammatory Index (DII^®) and breast cancer in Korean women and investigate whether the tumor’s hormone receptor status affects this association. In this case-control study, we enrolled 364 breast cancer patients and 364 age-matched controls. DII scores were calculated from dietary intake evaluated by a 106-item food frequency questionnaire. The DII score was significantly higher in cases than in controls. After adjusting for potential confounders, the odds ratio (OR) of breast cancer was higher in the highest DII tertile (OR = 3.68, 95% confidence interval (CI): 2.34–5.80, p for trend < 0.0001) than in the lowest tertile. We found that higher DII scores were related to an increased risk of breast cancer for estrogen receptor (ER)+/progesterone receptor (PR)+ tumors regardless of menopausal status (OR = 2.59, 95% CI: 1.37–4.88 in the highest DII category, p for trend = 0.01 for premenopausal women; OR = 11.00, 95% CI: 2.93–41.30 in the highest DII category, p for trend = 0.0004 for postmenopausal women), but not for ER−/PR− status. Our results suggested that the DII scores are positively associated with breast cancer risk in Korean women and that this relationship is more robust in ER+/PR+ tumors.

Vegetable-Fruit-Soybean Dietary Pattern and Breast Cancer: A Meta-Analysis of Observational Studies

Breast cancer is one of the most common cancers among women worldwide, and several studies have investigated the association of dietary patterns and breast cancer. However, findings of studies are inconclusive. Therefore, we aimed to conduct a meta-analysis to summarize the available data regarding the association of vegetable-fruit-soybean dietary pattern and breast cancer. A systematic literature search was conducted via PubMed, Web of Science and EMBASE to identify eligible cohort studies before February 2019. A total of 12 cohort studies were included in the meta-analysis. The summary relative risks (RR) with 95% CI were calculated with a fixed-effects model. The overall RR of breast cancer for the highest versus lowest intake of vegetable-fruit-soybean dietary pattern was 0.87 (95% CI, 0.82-0.91), with little heterogeneity (p=0.73, I2=0%). There was no obvious publication bias according to funnel plot and Begg's and Egger's test. In summary, the evidence from this meta-analysis indicates that vegetable-fruit-soybean dietary pattern was inversely associated with breast cancer. However, well-designed randomized controlled trials are needed to elicit the clear effect of vegetable-fruit-soybean dietary pattern and breast cancer. Women can reduce the risks of breast cancer by eating more fruits and vegetables and soybeans, which is a constructive suggestion.

Relationship between Plasma Fatty Acid Composition and Diet over Previous Years in the Italian Centers of the European Prospective Investigation into Cancer and Nutrition (EPIC)

Fatty acid levels in plasma phospholipids were related to food intake over the previous year as estimated by semiquantitative food frequency questionnaires compiled by 280 men and 246 women from the EPIC centers of Varese, Turin, Florence and Ragusa (Italy). Fatty acid content was determined by gas chromatography and analyzed in relation to age, sex and center. The most important finding was that plasma monounsaturated fatty acid levels, mainly oleic acid, were associated with olive oil consumption (r = 0.28 men, r = 0.19 women, both P <0.01). To our knowledge, this is the first time that these nonessential plasma fatty acids have been related to their dietary source in a population eating a varied and freely chosen diet. We confirmed that long-chain n-3 fatty acids in plasma phospholipids are associated with fish consumption and that odd chain 15: 0 and 17: 0 fatty acid levels are associated with dairy products and pizza-with-mozzarella consumption. N-6 polyunsaturated fatty acid levels reflected dietary intake of seed oils, mayonnaise and biscuits. Alcohol intake was positively associated with palmitic and palmitoleic acid and negatively associated with linoleic acid. These associations suggest indirect relations between alcohol consumption and other features of diet, and also that ethanol has an effect on fat metabolism. We found numerous indirect relationships (ie, not due to dietary consumption of food sources of the fatty acids) between plasma fatty acids and diet, which we propose as due to the influence of complex life-style factors.

Risk factors for breast cancer in a cohort of mammographic screening program: a nested case-control study within the FRiCaM study

Breast cancer is the most common cancer diagnosis and the leading cause of cancer death among women in the world, and differences across populations indicate a role of hormonal, reproductive and lifestyle factors. This study is based on a cohort of 78,050 women invited to undergo a mammogram by Local Health Authority of Milan, between 2003 and 2007. We carried out a nested case–control study including all the 3303 incident breast cancer cases diagnosed up to 2015, and 9909 controls matched by age and year of enrollment. Odds ratios (ORs) and corresponding 95% confidence intervals (CIs) were estimated using logistic regression models. The ORs were 0.88 (95% CI: 0.78–0.98) for an age at menarche ≥14 years and 1.39 (95% CI: 1.07–1.81) for an age of 30 years or older at first pregnancy. Body mass index (BMI) was positively associated with breast cancer risk in women older than 50 years (OR = 1.89, 95% CI: 1.54–2.31, for BMI≥30 vs. <20), while the association tended to be inverse in younger women. A high mammographic density increased breast cancer risk (OR = 2.61, 95% CI: 2.02–3.38 for density >75% vs. adipose tissue). The ORs were 1.67 (95% CI: 1.47–1.89) and 2.04 (95% CI: 1.38–3.00) for one first‐degree relative and two or more relatives affected by breast cancer, respectively. Our study confirms the role of major recognized risk factors for breast cancer in our population and provides the basis for a stratification of the participants in the mammographic screening according to different levels of risk.

DNA Damage, Mutagenesis and Cancer

A large number of chemicals and several physical agents, such as UV light and γ-radiation, have been associated with the etiology of human cancer. Generation of DNA damage (also known as DNA adducts or lesions) induced by these agents is an important first step in the process of carcinogenesis. Evolutionary processes gave rise to DNA repair tools that are efficient in repairing damaged DNA; yet replication of damaged DNA may take place prior to repair, particularly when they are induced at a high frequency. Damaged DNA replication may lead to gene mutations, which in turn may give rise to altered proteins. Mutations in an oncogene, a tumor-suppressor gene, or a gene that controls the cell cycle can generate a clonal cell population with a distinct advantage in proliferation. Many such events, broadly divided into the stages of initiation, promotion, and progression, which may occur over a long period of time and transpire in the context of chronic exposure to carcinogens, can lead to the induction of human cancer. This is exemplified in the long-term use of tobacco being responsible for an increased risk of lung cancer. This mini-review attempts to summarize this wide area that centers on DNA damage as it relates to the development of human cancer.

Dietary fibre intake and risk of breast cancer: A systematic review and meta-analysis of epidemiological studies

Current evidence from randomised controlled trials on the effects of dietary fibre intake on breast cancer risk is inconsistent. We conducted a meta-analysis to determine the effectiveness of dietary fibre intake in reducing breast cancer risk. We searched for prospective and case-control studies on dietary fibre intake and breast cancer risk in the English language through March 2016. Twenty-four epidemiologic studies obtained through the PubMed, Embase, Web of Science, and Cochrane Library databases were systematically reviewed. A random-effects model was used to compute the pooled risk estimates by extracting the risk estimate of the highest and lowest reported categories of intake from each study. The meta-analyses showed a 12% decrease in breast cancer risk with dietary fibre intake. The association between dietary fibre intake and breast cancer risk was significant when stratified according to Jadad scores, study types, and menopause status. Dose-response analysis showed that every 10 g/d increment in dietary fibre intake was associated with a 4% reduction in breast cancer risk, and little evidence of publication bias was found. Thus, dietary fibre consumption is significantly associated with a reduced risk of breast cancer, particularly in postmenopausal women.

Cucurmin, anticancer, & antitumor perspectives: A comprehensive review

Cucurmin, a naturally yellow component isolated from turmeric, ability to prevent various life-style related disorders. The current review article mainly emphasizes on different anticancer perspectives of cucurmin, i.e., colon, cervical, uterine, ovarian, prostate head and neck, breast, pulmonary, stomach and gastric, pancreatic, bladder oral, oesophageal, and bone cancer. It holds a mixture of strong bioactive molecule known as cucurminoids that has ability to reduce cancer/tumor at initial, promotion and progression stages of tumor development. In particular, these compounds block several enzymes required for the growth of tumors and may therefore involve in tumor treatments. Moreover, it modulates an array of cellular progressions, i.e., nitric oxide synthetase activity, protein kinase C activity, epidermal growth factor (EGF) receptor intrinsic kinase activity, nuclear factor kappa (NF-kB) activity, inhibiting lipid peroxidation and production of reactive oxygen species. However, current manuscript summarizes most of the recent investigations of cucurmin but still further research should be conducted to explore the role of curcumin to mitigate various cancers.

Outdoor Light at Night and Breast Cancer Incidence in the Nurses' Health Study II

BACKGROUND

Animal and epidemiologic studies suggest that exposure to light at night (LAN) may disrupt circadian patterns and decrease nocturnal secretion of melatonin, which may disturb estrogen regulation, leading to increased breast cancer risk.

OBJECTIVES

We examined the association between residential outdoor LAN and breast cancer incidence using data from the nationwide U.S.-based Nurses' Health Study II cohort.

METHODS

We followed 109,672 women from 1989 through 2013. Cumulative LAN exposure was estimated using time-varying satellite data for a composite of persistent nighttime illumination at ∼1 km² scale for each residence during follow-up. Incident invasive breast cancer cases were confirmed by medical record review. We used Cox proportional hazard models to calculate hazard ratios (HRs) and 95% confidence intervals (CIs), adjusting for anthropometric, reproductive, lifestyle, and socioeconomic risk factors.

RESULTS

Over 2,187,425 person-years, we identified 3,549 incident breast cancer cases. Based on a fully adjusted model, the estimated HR for incident breast cancer with an interquartile range (IQR) (31.6 nW/cm²/sr) increase in cumulative average outdoor LAN was 1.05 (95% CI: 1.00, 1.11). An association between LAN and breast cancer appeared to be limited to women who were premenopausal at the time of a case [HR=1.07 (95% CI: 1.01, 1.14) based on 1,973 cases vs. HR=1.00 (95% CI: 0.91, 1.09) based on 1,172 cases in postmenopausal women; p-interaction=0.08]. The LAN-breast cancer association was observed only in past and current smokers at the end of follow-up [HR=1.00 (95% CI: 0.94, 1.07) based on 2,215 cases in never smokers; HR=1.10 (95% CI: 1.01, 1.19) based on 1,034 cases in past smokers vs. HR=1.21 (95% CI: 1.07, 1.37) for 300 cases in current smokers; p-interaction=0.08].

CONCLUSIONS

Although further work is required to confirm our results and to clarify potential mechanisms, our findings suggest that exposure to residential outdoor light at night may contribute to invasive breast cancer risk. https://doi.org/10.1289/EHP935.

The dietary patterns are a modifying risk factor for breast cancer: An ecological study

A comparative study of dietary patterns (DPs) with breast cancer (BC) incidence in different countries has been performed. It was established that in the countries with a high incidence of BC (76 per 100 000 people) the levels of consumption of the "nutrients of animal foods," "fruits and beverages," and "alcoholic drinks" are 1.5-2 times higher and that of "cereals and vegetables" is 1.5 times lower than in the countries with a low incidence of BC (35 per 100 000). In Mediterranean countries, where incidence of BC is 51 per 100 000, the levels of consumption of "animal foods" is two times lower than the levels of consumption of "cereals and vegetables." A method of assessing the impact of DPs on the incidence of BC has been proposed.

The role of background diet on the effects of eicosapentaenoic acid and docosahexaenoic acid supplementation in healthy pre-menopausal women: a randomized, cross-over, controlled study

Background

The links between dietary fat intake, polyunsaturated fatty acid intake and breast cancer risk remain equivocal, with some studies pointing to improvements in risk upon omega-3 supplementation. However, the background diet is poorly controlled in most studies, potentially confounding this link. Therefore, this study examined the hypothesis that in order to see the benefits of omega-3 fatty acid supplementation, the background diet must be low in fat.

Methods

Of the 56 healthy, pre-menopausal women randomized to one of two experimental arms, consisting of a two-treatment, randomized, cross-over design, 41 completed the 10 month intervention. The two diet phases (habitual and low-fat) were separated by a washout phase, each lasting 3 menstrual cycles. During each diet phase, women were supplemented with 1.2 g eicosapentaenoic acid + docosahexaenoic acid per day.

Results

Red blood cell fatty acid composition indicated that more eicosapentaenoic acid and docosahexaenoic acid was incorporated in the low-fat diet than the habitual diet, though both diet phases resulted in significant increases in the omega-3 to omega-6 ratio. In the context of omega-3 supplementation in breast cancer risk reduction, we also measured fatty acid incorporation into nipple aspirate fluid. Similar changes to red blood cells were noted in nipple aspirate fluid, with higher incorporation of eicosapentaenoic acid in the low-fat diet phase.

Conclusions

These data suggest that the total level of dietary fat has some direct impact on fatty acid partitioning in addition to the recognized importance of fatty acid ratios, and supports the hypothesis that dietary fat intake must be considered a confounder in supplementation trials. Additionally, we demonstrate that n3 supplementation both reaches and imparts improvements in lipid content and n3:n6 at the target breast tissue.

Trial registration

Trial was been retrospectively registered at clinicaltrials.gov (RegNCT02816125).

Genetically Predicted Body Mass Index and Breast Cancer Risk: Mendelian Randomization Analyses of Data from 145,000 Women of European Descent

BACKGROUND

Observational epidemiological studies have shown that high body mass index (BMI) is associated with a reduced risk of breast cancer in premenopausal women but an increased risk in postmenopausal women. It is unclear whether this association is mediated through shared genetic or environmental factors.

METHODS

We applied Mendelian randomization to evaluate the association between BMI and risk of breast cancer occurrence using data from two large breast cancer consortia. We created a weighted BMI genetic score comprising 84 BMI-associated genetic variants to predicted BMI. We evaluated genetically predicted BMI in association with breast cancer risk using individual-level data from the Breast Cancer Association Consortium (BCAC) (cases  =  46,325, controls  =  42,482). We further evaluated the association between genetically predicted BMI and breast cancer risk using summary statistics from 16,003 cases and 41,335 controls from the Discovery, Biology, and Risk of Inherited Variants in Breast Cancer (DRIVE) Project. Because most studies measured BMI after cancer diagnosis, we could not conduct a parallel analysis to adequately evaluate the association of measured BMI with breast cancer risk prospectively.

RESULTS

In the BCAC data, genetically predicted BMI was found to be inversely associated with breast cancer risk (odds ratio [OR]  =  0.65 per 5 kg/m2 increase, 95% confidence interval [CI]: 0.56-0.75, p = 3.32 × 10-10). The associations were similar for both premenopausal (OR   =   0.44, 95% CI:0.31-0.62, p  =  9.91 × 10-8) and postmenopausal breast cancer (OR  =  0.57, 95% CI: 0.46-0.71, p  =  1.88 × 10-8). This association was replicated in the data from the DRIVE consortium (OR  =  0.72, 95% CI: 0.60-0.84, p   =   1.64 × 10-7). Single marker analyses identified 17 of the 84 BMI-associated single nucleotide polymorphisms (SNPs) in association with breast cancer risk at p < 0.05; for 16 of them, the allele associated with elevated BMI was associated with reduced breast cancer risk.

CONCLUSIONS

BMI predicted by genome-wide association studies (GWAS)-identified variants is inversely associated with the risk of both pre- and postmenopausal breast cancer. The reduced risk of postmenopausal breast cancer associated with genetically predicted BMI observed in this study differs from the positive association reported from studies using measured adult BMI. Understanding the reasons for this discrepancy may reveal insights into the complex relationship of genetic determinants of body weight in the etiology of breast cancer.

Consumption of Fresh Yellow Onion Ameliorates Hyperglycemia and Insulin Resistance in Breast Cancer Patients During Doxorubicin-Based Chemotherapy: A Randomized Controlled Clinical Trial

PURPOSE

Doxorubicin has been found to be associated with insulin resistance in animal models. Onion, a so-called functional food, is noted to affect the insulin signaling pathway of diabetes in vitro. To our knowledge, this is the first study to investigate the effects of consuming fresh yellow onions on insulin-related indices compared with a low-onion-containing diet among breast cancer (BC) patients treated with doxorubicin.

METHODS

This parallel-design, randomized, triple-blind, controlled clinical trial was conducted on 56 eligible BC patients (aged 30-63 years), diagnosed with invasive ductal carcinoma. Following their second cycle of chemotherapy, subjects were assigned in a stratified-random allocation to receive body mass index-dependent 100 to 160 g/d of onion as high onion group (HO; n = 28) or 30 to 40 g/d small onions in low onion group (LO; n = 28) for 8 weeks intervention. Participants, care givers, and those who assessed laboratory analyses were blinded to the assignments (IRCT Registry No.: IRCT2012103111335N1).

RESULTS

The compliance level of participants in the analysis was as high as 87.85%. A total of 23 available cases was analyzed in each group. The daily use of HO resulted in a significant decrease in serum fasting blood glucose and insulin levels in comparison with LO, over the period of study ( P < .001). Posttreatment with HO showed a significant decrease in homeostasis model of assessment-insulin resistance relative to changes in the LO group ( P < .05). A comparison of the changes that occurred throughout pre- and postdose treatments indicated improved quantitative insulin sensitivity check index ( P < .05) and controls on C-peptide in the HO group ( P < .05).

CONCLUSIONS

The present study demonstrated the effectiveness of onion to ameliorate hyperglycemia and insulin resistance in BC during doxorubicin-based chemotherapy.

Dietary patterns and breast cancer risk in a prospective Japanese study

BACKGROUND

The association between dietary patterns and breast cancer has been inconsistent.

METHODS

This study examined associations between dietary patterns and risk of developing breast cancer among 23,172 women from the Japan Collaborative Cohort Study, including 119 incidences of breast cancer diagnosed during a median 16.9-year follow-up period. Factor analysis was conducted to obtain dietary patterns, and Cox proportional models were used to estimate hazard ratios (HR) and 95 % confidence intervals (95 % CI) for breast cancer morbidity.

RESULTS

Three dietary patterns were identified: ''vegetable pattern'' (vegetables, potatoes, seaweed, tofu, fruits, fresh fish, eggs, and miso soup); ''animal food pattern'' (meat, deep-fried foods, fried vegetables, fish paste and salt-preserved fish); and "dairy product pattern'' (milk, dairy products, fruits, coffee and tea). After adjusting for potential confounders, the vegetable and dairy product patterns were not significantly associated with risk of breast cancer. However, the animal food pattern was significantly associated with a decreased risk of breast cancer morbidity among premenopausal women by HR 0.47 for the 2nd tertile (95 % CI 0.22-1.00) and HR 0.42 for the 3rd tertile (95 % CI 0.18-0.93), compared with the bottom tertile (p for trend 0.04).

CONCLUSION

We found no significant association between the vegetable and dairy product dietary patterns and breast cancer risk; however, an animal product diet may reduce risk of breast cancer among premenopausal Japanese women.

Linoleic acid and breast cancer risk: a meta-analysis

Objective

Prior studies on linoleic acid, the predominant n-6 fatty acid, and breast cancer risk have generated inconsistent results. We performed a meta-analysis to summarize the evidence regarding the relationship of dietary and serum linoleic acid with breast cancer risk.

Design

Pertinent studies were identified by a search of PubMed and EMBASE. The fixed- or random-effect pooled measure was selected based on between-study heterogeneity.

Results

Eight prospective cohort studies and four prospective nested case–control studies, involving 10 410 breast cancer events from 358 955 adult females across different countries, were included in present study. Compared with the lowest level of linoleic acid, the pooled relative risk (RR; 95 % CI) of breast cancer was 0·98 (0·93, 1·04) for the highest level of linoleic acid. The pooled RR (95 % CI) for dietary and serum linoleic acid were 0·99 (0·92, 1·06) and 0·98 (0·88, 1·08), respectively. The RR (95 % CI) of breast cancer was 0·97 (0·91, 1·04), 0·95 (0·85, 1·07), 0·96 (0·86, 1·07), 0·98 (0·87, 1·10) and 0·99 (0·85, 1·14) for linoleic acid intake of 5, 10, 15, 20 and 25 g/d, respectively. The risk of breast cancer decreased by 1 % (RR=0·99; 95 % CI 0·93, 1·05) for every 10 g/d increment in linoleic acid intake.

Conclusions

This meta-analysis indicated that both dietary linoleic acid intake and serum linoleic acid level were associated with decreased risk of breast cancer, although none of the associations were statistically significant. Further investigations are warranted.

Serum and hair zinc levels in breast cancer: a meta-analysis

Many studies have investigated the association between serum/hair zinc levels and breast cancer, but the results were inconsistent. To compare the serum and hair zinc levels in women with breast cancer and controls, we conducted a systematic literature search of PubMed, Web of Science, Cochrane Library and Embase to identify relevant studies with publication dates up through November 2014. Based on a random effects model, summary standard mean differences (SMDs) and the corresponding 95% confidence intervals (CIs) were used to compare the serum and hair zinc levels in women with breast cancer and controls. Fourteen studies that investigated serum zinc levels and seven studies that assessed hair zinc levels were included. Our study observed no difference in serum zinc levels between breast cancer cases and controls (SMD (95%CI): -0.65[-1.42, 0.13]). However, we determined that hair zinc levels were lower in women with breast cancer compared with those of controls (SMD (95%CI): -1.99[-3.46, -0.52]). In conclusion, this study was the first to provide evidence that hair zinc levels in female breast cancer patients are lower than in controls; however, there was no significant difference in serum zinc levels between female breast cancer patients and controls.

Comparison of essential and toxic elements in esophagus, lung, mouth and urinary bladder male cancer patients with related to controls

There is a compelling evidence in support of negative associations between essential trace and toxic elements in different types of cancer. The aim of the present study was to investigate the relationship between carcinogenic (As, Cd, Ni) and anti-carcinogenic (Se, Zn) trace elements in scalp hair samples of different male cancerous patients (esophagus, lung, mouth, and urinary bladder). For comparative purposes, the scalp hair samples of healthy males of the same age group (ranged 35-65 years) as controls were analyzed. Both controls and patients have the same socioeconomic status, localities, dietary habits, and smoking locally made cigarette. The scalp hair samples were oxidized by 65% nitric acid: 30% hydrogen peroxide (2:1) ratio in microwave oven followed by atomic absorption spectrometry. The validity and accuracy of the methodology were checked using certified reference material of human hair BCR 397. The mean concentrations of As, Cd, and Ni were found to be significantly higher in scalp hair samples of patients having different cancers as compared to the controls, while reverse results were obtained in the case of Se and Zn levels (p < 0.01). The study revealed that the carcinogenic processes are significantly affecting the trace elements burden and mutual interaction of essential trace and toxic elements in the cancerous patients.

Normolipidic dietary fat modifies circulating Renin-Angiotensin system-regulating aminopeptidase activities in rat with breast cancer

HYPOTHESIS

Renin-angiotensin system (RAS) has been considered not only as a regulator of systemic volume and electrolyte balance but also has been recently involved in various pathological processes such as cancer. In the etiology of breast cancer, dietary factors have been analyzed and especially the influence of dietary fat has been studied, but the underlying mechanisms remain unclear. In this study, we analyzed RAS-regulating enzymes in serum of rats with N-methyl nitrosourea (NMU)-induced breast cancer fed with different diets.

STUDY DESIGN

Four groups of rats were injected intraperitoneally with 3 doses of 50 mg/kg body weight of NMU at different days after birth and were fed with an AIN-93 commercial diet or AIN-93 diets with 4% fat constituted respectively by extra virgin olive oil, refined sunflower oil, and refined sunflower oil enriched to 50% with oleic acid.

METHOD

After sacrifice, blood and tumor samples were collected by spectrophotometric determinations of RAS-regulating enzymes in plasma and histopathology studies.

RESULTS

We show that the type of dietary fat does not influence latency period, incidence of animals with tumors, incidence of mortality, or tumor yield per rat. However, changes were observed in tumor volume and the histopathology. The type of dietary fat also differently modified the enzymes involved in RAS regulation.

CONCLUSIONS

It might suggest that one of the mechanisms by which dietary fat affects breast cancer is the modification of the RAS system, which may be consider as a new target for integrative therapies.

Factors influencing the mammography utilization among Taiwanese women with intellectual disabilities, a nationwide population-based study

Women with intellectual disabilities (ID) have cognitive impairment and communication difficulties; for both caregivers and clinical personnel, discovering the early symptoms of breast cancer among women with ID is challenging. The mammography utilization rate of women with ID was significantly lower than that of women in the general population. This study employed a 2008 database of people with disabilities in Taiwan as a research target and analyzed the mammography utilization rate of women with ID aged 50–69 years. In addition, relevant factors influencing mammography utilization among women with ID were also investigated. A total of 4370 participants were recruited and the majority were illiterate or had elementary-level educations (82.27%). The majority of the participants had ID that was more severe than mild (83.80%). The mammography utilization rate of women with ID was 4.32%, which was significantly lower than that of women in the general population (12%). The mammography utilization rate among women with ID who were married, had higher education levels, and had been diagnosed with cancer, diabetes, or mild ID was significantly higher. However, the mammography utilization rate among women with ID, who had elementary-level educations or were illiterate, was only 4.03%. The utilization rate among women with profound ID was only 2.65%. Women with ID who had undergone pap smears or had utilized adult preventive health services demonstrated a significantly higher mammography utilization rate. This study identified that education level, a diagnosis of diabetes, and the application of pap smears or adult preventive health services were primary factors that influenced the mammography utilization rate among women with ID. This study also observed that in Taiwan, the mammography utilization rate of women with ID was lower than that of pap smears and adult preventive health services, and was only half of that of people with disabilities. An unequal situation existed in regard to the acceptance of breast cancer screening among women with ID, and a different form of strategic planning must be adopted in public health policy. Because ID differs from other disabilities and most women with ID are illiterate, tailored courses are required to train primary caregivers and clinical personnel in providing knowledge and services. The objectives are to diagnose breast cancer at an early stage to decrease the risk of mortality and ensure their rights to health.

Beliefs and perceptions about the causes of breast cancer: a case-control study

BACKGROUND

Attributions of causality are common for many diseases, including breast cancer. The risk of developing breast cancer can be reduced by modifications to lifestyle and behaviours to minimise exposure to specific risk factors, such as obesity. However, these modifications will only occur if women believe that certain behaviours/lifestyle factors have an impact on the development of breast cancer.

METHOD

The Breast Cancer, Environment and Employment Study is a case-control study of breast cancer conducted in Western Australia between 2009 and 2011. As part of the study 1109 women with breast cancer and 1633 women without the disease completed a Risk Perception Questionnaire in which they were asked in an open-ended question for specific cause/s to the development of breast cancer in themselves or in others. The study identified specific causal beliefs, and assessed differences in the beliefs between women with and without breast cancer.

RESULTS

The most common attributions in women without breast cancer were to familial or inherited factors (77.6%), followed by lifestyle factors, such as poor diet and smoking (47.1%), and environmental factors, such as food additives (45.4%). The most common attributions in women with breast cancer were to mental or emotional factors (46.3%), especially stress, followed by lifestyle factors (38.6%) and physiological factors (37.5%), particularly relating to hormonal history.

CONCLUSIONS

While the majority of participants in this study provided one or more causal attributions for breast cancer, many of the reported risk factors do not correspond to those generally accepted by the scientific community. These misperceptions could be having a significant impact on the success of prevention and early detection programs that seek to minimise the pain and suffering caused by this disease. In particular, women who have no family history of the disease may not work to minimise their exposure to the modifiable risk factors.

Concentration of cd, pb, hg, and se in different parts of human breast cancer tissues

Breast cancer is the major cause of cancer morbidity and mortality between women in the world. Metals involved in environmental toxicology are closely related to tumor growth and cancer. On the other hand, some metals such as selenium have anticarcinogenic properties. The aim of this study is to determine the concentration of cadmium, lead, mercury, and selenium in separated parts of tegmen, tumor, tumor adiposity, and tegmen adiposity of 14 breast cancer tissues which have been analyzed by graphite furnace atomic absorption (AA-670) and ICP-OES (ULTIMA 2CE). Our results show that Se and Hg have maximum and minimum concentration, respectively. Statistical analysis reveals no significant differences between metal accumulations in different parts of cancer tissues (P > 0.05) and this observation might be due to the close relation of separated parts of fatty breast organ. Thus, we could conclude that a high level of these heavy metals is accumulated in Iranian cancerous breasts and their presence can be one of the reasons of cancer appearance.

Estrogenic endocrine-disrupting chemicals: molecular mechanisms of actions on putative human diseases

Endocrine-disrupting chemicals (EDC), including phthalates, bisphenol A (BPA), phytoestrogens such as genistein and daidzein, dichlorodiphenyltrichloroethane (DDT), and 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD), are associated with a variety of adverse health effects in organisms or progeny by altering the endocrine system. Environmental estrogens, including BPA, phthalates, and phytoestrogens, are the most extensively studied and are considered to mimic the actions of endogenous estrogen, 17β-estradiol (E2). Diverse modes of action of estrogen and estrogen receptors (ERα and ERβ) have been described, but the mode of action of estrogenic EDC is postulated to be more complex and needs to be more clearly elucidated. This review examines the adverse effects of estrogenic EDC on male or female reproductive systems and molecular mechanisms underlying EDC effects that modulate ER-mediated signaling. Mechanisms of action for estrogenic EDC may involve both ER-dependent and ER-independent pathways. Recent findings from systems toxicology of examining estrogenic EDC are also discussed.

Dietary patterns and breast cancer risk in the California Teachers Study cohort

BACKGROUND

Evidence that diet is associated with breast cancer risk is inconsistent. Most studies have examined risks associated with specific foods and nutrients, rather than measures of overall diet.

OBJECTIVE

This study aimed to evaluate dietary patterns and their relation to breast cancer risk in a large cohort of women.

DESIGN

Data from 91,779 women in the California Teachers Study cohort were analyzed, including data from 4140 women with a diagnosis of invasive breast cancer made between 1995 and 2009. Five predominant dietary patterns were identified by using principal components factor analysis: a plant-based diet, high in fruit and vegetables; a high-protein, high-fat diet, high in meats, eggs, fried foods, and high-fat condiments; a high-carbohydrate diet, high in convenience foods, pasta, and bread products; an ethnic diet, high in legumes, soy-based foods, rice, and dark-green leafy vegetables; and a salad and wine diet, high in lettuce, fish, wine, low-fat salad dressing, and coffee and tea.

RESULTS

The plant-based pattern was associated with a reduction in breast cancer risk (RR: 0.85; 95% CI: 0.76, 0.95 for the highest compared with the lowest consumption quintile; P-trend = 0.003); risk reduction was greater for estrogen receptor-negative progesterone receptor-negative (ER-PR-) tumors (RR: 0.66; 95% CI: 0.48, 0.91; P-trend = 0.03). The salad and wine pattern was associated with an increased risk of estrogen receptor-positive progesterone receptor-positive tumors (RR: 1.29; 95% CI: 1.12, 1.49); this effect was only slightly attenuated after adjustment for alcohol consumption.

CONCLUSION

The finding that greater consumption of a plant-based dietary pattern is associated with a reduced breast cancer risk, particularly for ER-PR- tumors, offers a potential avenue for prevention.

Prospective association between dietary fiber intake and breast cancer risk

BACKGROUND

Mechanistic hypotheses suggest a potential effect of dietary fiber on breast carcinogenesis through the modulation of insulin-like growth factor bioactivity, estrogen metabolism and inflammation. An association between dietary fiber intake and breast cancer risk has been suggested in epidemiological studies but remains inconclusive. In particular, data is lacking regarding the different types of dietary fibers.

OBJECTIVE

The objective was to investigate the prospective relationship between dietary fiber intake and breast cancer risk, taking into account different types of dietary fiber (overall, insoluble, soluble and from different food sources: cereals, vegetables, fruits and legumes).

DESIGN

4684 women from the SU.VI.MAX cohort were included in this analysis as they completed at least three 24h-dietary records within the first two years of follow-up. Among them, 167 incident invasive breast cancers were diagnosed during a median follow-up of 12.6 years (between 1994 and 2007). The associations between quartiles of dietary fiber intake and breast cancer risk were characterized using multivariate Cox proportional hazards models.

RESULTS

Total fiber intake was not associated with breast cancer risk (HR(Quartile4vs.Quartile1) = 1.29 (95%CI 0.66-2.50), P-trend = 0.5), nor was fiber intake from cereals (P-trend = 0.1), fruits (P-trend = 0.9) and legumes (P-trend = 0.3). In contrast, vegetable fiber intake was related to a decreased risk of breast cancer (HR(Q4vs.Q1) = 0.50 (0.29-0.88), P-trend = 0.03). Overall vegetable intake (in g/day) was not associated with breast cancer risk (P-trend = 0.2).

CONCLUSION

This prospective study suggests that vegetable fiber intake may contribute to reduce breast cancer risk, in line with experimental mechanistic data.

Genetic polymorphisms in RAD23B and XPC modulate DNA repair capacity and breast cancer risk in Puerto Rican women

Studies have shown that DNA repair capacity (DRC) is significantly decreased in breast cancer patients, but the molecular causes of inter-individual variation in DRC are unknown. We hypothesized that genetic variation in the nucleotide excision repair pathway genes can modulate DRC and breast cancer risk in Puerto Rican women. A total of 228 breast cancer cases and 418 controls were recruited throughout Puerto Rico. For all study participants, eight single nucleotide polymorphisms (SNPs) in the genes XPC, XPD, and RAD23B were genotyped using a TaqMan PCR, and the DRC levels of UV induced-DNA damage was measured in peripheral lymphocytes using a host cell reactivation assay. After adjustment for confounders, RAD23B rs1805329 (Ala249Val) was found to be significantly associated with breast cancer risk under all models tested (P < 0.001). There was also a significant association between breast cancer risk and RAD23B rs10739234 (intronic) under the recessive model (P = 0.003, OR: 2.72, 95% CI: 1.40-5.30). In cases, there was a statistically significant difference in mean DRC per genotype for RAD23B rs1805329 (P < 0.001) and XPC rs2607775 (P = 0.002). When we modeled the combined effect of multiple SNPs that each independently affected DRC on cancer risk, we observed incremental augmentations in risk with increasing number of risk genotypes at those loci (P overall model <0.001). The increase in adverse genotypes was also correlated with a progressive decrease in DRC values. Our data indicate an additive effect of the NER SNPs on DRC and breast cancer risk in Puerto Rican women.

Coffee Consumption Associated with Increased Mortality of Women with Breast Cancer

BACKGROUND

There has been some speculation that caffeine consumption may affect breast cancer. Most case-control studies have not documented evidence of a caffeine-breast cancer incidence link; however, there has been very little analysis of the possible effects of caffeine consumption on breast cancer survival.

METHODS

We examined overall a 20-year survival of 96 women treated for breast cancer between 1990 and 1994. As part of their health history, these women were asked about coffee drinking.

RESULTS

Fifty-three women drank one cup a day (79.2% survival), 22 women had two cups a day (72.7% survival), and 21 women drank three or more cups a day (42.9% survival). The effect of coffee consumption on survival was significant (p=0.006, the log rank test). To exclude the effects of lymph node involvement, age at diagnosis, and smoking history, Cox regression was performed. The effect of coffee was significant (p=0.001), independent of the effects of lymph node involvement (p=0.012) and age at diagnosis (p=0.014), and unrelated to a smoking history (p=0.721).

CONCLUSION

Fatigued breast cancer survivors have an abnormal proinflammatory cytokine activity, an average of 5 years after diagnosis, as well as significant serum cortisol derangements compared to other survivors. One possible interpretation of our results suggests that there is an abnormal hypothalamic-pituitary-adrenal axis functioning in breast cancer patients with persistent fatigue, who might be using coffee to self-medicate. In other words, coffee consumption in the present study might be a surrogate marker for fatigue. Because of the paucity of data regarding caffeine intake, poor sleep, fatigue, and breast cancer survival, further studies could be worthwhile.

A comparative genotoxicity study of a supraphysiological dose of triiodothyronine (T₃) in obese rats subjected to either calorie-restricted diet or hyperthyroidism

This study was designed to determine the genotoxicity of a supraphysiological dose of triiodothyronine (T₃) in both obese and calorie-restricted obese animals. Fifty male Wistar rats were randomly assigned to one of the two following groups: control (C; n = 10) and obese (OB; n = 40). The C group received standard food, whereas the OB group was fed a hypercaloric diet for 20 weeks. After this period, half of the OB animals (n = 20) were subjected to a 25%-calorie restriction of standard diet for 8 weeks forming thus a new group (OR), whereas the remaining OB animals were kept on the initial hypercaloric diet. During the following two weeks, 10 OR animals continued on the calorie restriction diet, whereas the remaining 10 rats of this group formed a new group (ORS) given a supraphysiological dose of T₃ (25 µg/100 g body weight) along with the calorie restriction diet. Similarly, the remaining OB animals were divided into two groups, one that continued on the hypercaloric diet (OB, n = 10), and one that received the supraphysiological dose of T₃ (25 µg/100 g body weight) along with the hypercaloric diet (OS, n = 10) for two weeks. The OB group showed weight gain, increased adiposity, insulin resistance, increased leptin levels and genotoxicity; T₃ administration in OS animals led to an increase in genotoxicity and oxidative stress when compared with the OB group. The OR group showed weight loss and normalized levels of adiposity, insulin resistance, serum leptin and genotoxicity, thus having features similar to those of the C group. On the other hand, the ORS group, compared to OR animals, showed higher genotoxicity. Our results indicate that regardless of diet, a supraphysiological dose of T₃ causes genotoxicity and potentiates oxidative stress.

Comparing an olive oil-enriched diet to a standard lower-fat diet for weight loss in breast cancer survivors: a pilot study

BACKGROUND

Traditional diets that include moderate to high intakes of extra virgin olive oil have been related to a decrease in breast cancer risk. We hypothesized that an olive oil-enriched diet would lead to greater weight loss and acceptance, compared with a standard diet, in women previously diagnosed with invasive breast cancer.

METHODS

Participants consumed a National Cancer Institute (NCI) diet (total fat > 15% and < 30%) and a plant-based olive oil diet (PBOO; > or = 3 tablespoons of olive oil/day) for 8 weeks, each with random assignment to the order. We established a weight loss goal of at least 5% of baseline weight. After completion of the two diet trials, each participant self-selected one of the diets for an additional 6 months of follow-up for weight management. Body measures were done before and after each diet and after follow-up; fasting blood samples were collected after each diet and after follow-up.

RESULTS

Forty-four overweight women started and 28 completed the 44-week protocol. Twelve (80%) of the 15 women who started with the PBOO diet achieved a weight loss of > or = 5% compared to 4 (31%) of the 13 who started with the NCI diet (p < 0.01). Nineteen of the 22 women eligible for follow-up chose the PBOO diet, and all completed the study. Of the 3 women who chose the NCI diet for follow-up, 1 completed the study. The PBOO diet resulted in lower triglycerides (NCI 105 +/- 46 mg/dL, PBOO 96 +/- 37 mg/dL, p = 0.06) and higher high-density lipoprotein cholesterol (HDL-C) (NCI 64 +/- 13 mg/dL, PBOO 68 +/- 12 mg/dL, p = 0.001).

CONCLUSIONS

An olive oil-enriched diet brought about greater weight loss than a lower-fat diet in an 8-week comparison. Moreover, these women chose, overwhelmingly, the olive oil-enriched diet for 6 months of follow-up. An olive oil-enriched diet may be more efficacious for weight loss in breast cancer survivors than a standard lower-fat diet.

Inhibitory effect of luteolin on estrogen biosynthesis in human ovarian granulosa cells by suppression of aromatase (CYP19)

Inhibition of aromatase, the key enzyme in estrogen biosynthesis, is an important strategy in the treatment of breast cancer. Several dietary flavonoids show aromatase inhibitory activity, but their tissue specificity and mechanism remain unclear. This study found that the dietary flavonoid luteolin potently inhibited estrogen biosynthesis in a dose- and time-dependent manner in KGN cells derived from human ovarian granulosa cells, the major source of estrogens in premenopausal women. Luteolin decreased aromatase mRNA and protein expression in KGN cells. Luteolin also promoted aromatase protein degradation and inhibited estrogen biosynthesis in aromatase-expressing HEK293A cells, but had no effect on recombinant expressed aromatase. Estrogen biosynthesis in KGN cells was inhibited with differing potencies by extracts of onion and bird chili and by four other dietary flavonoids: kaempferol, quercetin, myricetin, and isorhamnetin. The present study suggests that luteolin inhibits estrogen biosynthesis by decreasing aromatase expression and destabilizing aromatase protein, and it warrants further investigation as a potential treatment for estrogen-dependent cancers.

Identification of the prevalent BRCA1 and BRCA2 mutations in the female population of Puerto Rico

Mutations in the breast cancer 1, early onset (BRCA1) and breast cancer 2 (BRCA2) genes are responsible for the majority of hereditary breast cancers. Knowledge of the incidence and prevalence of BRCA mutations in a specific population or ethnic group is necessary to provide accurate genetic counseling for breast cancer patients and their families; however, these data have not been gathered in the population of Puerto Rico. We conducted a retrospective study of female breast cancer patients undergoing genetic testing for BRCA mutations in the highest-volume breast surgery practices in San Juan, Puerto Rico. Data collection includes three-generation family cancer history and results from complete BRCA sequencing. A total of six different deleterious mutations were observed, including one mutation in BRCA1 and five mutations in BRCA2. Three recurrent mutations (BRCA1 del exon1-2, BRCA2 4150G>T, and BRCA2 6027del4) account for over 70% of all the BRCA mutations observed in this study population. This study examines for the first time the characteristics of hereditary breast cancer in Puerto Rico and assesses the accuracy of existing genetic risk assessment tools in that population. This data is expected to contribute to providing accurate and efficient tools for the clinical management of hereditary breast cancer in Puerto Rico.

Dietary fat and breast cancer in postmenopausal women according to ethnicity and hormone receptor status: the Multiethnic Cohort Study

Dietary fat has been widely studied as a risk factor for breast cancer, with little consistency in results. The Multiethnic Cohort Study (MEC) provides an opportunity to assess this relationship for possible heterogeneity across different racial/ethnic groups, as well as by stratification on several other variables associated with risk. Therefore, we investigated the associations between dietary fat, overall and by type, and breast cancer risk among 85,089 postmenopausal women who entered the MEC by completing a comprehensive dietary questionnaire in 1993 to 1996. During a mean follow-up of 12 years, 3,885 incident invasive breast cancer cases were identified. The multivariate HR [95% confidence interval (CI)] for the highest versus lowest quintile of intake was 0.94 (95% CI, 0.85-1.05) for total fat and 0.93 (95% CI, 0.83-1.04) for saturated fat. Other specific types of dietary fat, including individual fatty acids, were not related to risk of postmenopausal breast cancer. We found no heterogeneity in these null findings across the five ethnic groups. Furthermore, we found no evidence that the association between dietary fat and postmenopausal breast cancer risk differed by estrogen/progesterone receptor status, tumor stage, body mass index, hormone replacement therapy use, follow-up period, family history of breast cancer, and smoking status at baseline. In conclusion, this comprehensive prospective analysis in the MEC does not support a role of adult intake of dietary fat in the etiology of postmenopausal breast cancer.

Diets and hormonal levels in postmenopausal women with or without breast cancer

The role of diet in breast cancer (BC) risk is unclear. Fiber could reduce BC risk, through the enterohepatic circulation of estrogens. We examined the relationship between diet and sex hormones in postmenopausal women with or without BC. Thirty-one postmenopausal women (10 omnivores, 11 vegetarians, and 10 BC omnivores) were recruited. Dietary records (5 days) and hormone levels (3 days) were evaluated on 4 occasions over 1 yr. Vegetarians showed a lower fat/fiber ratio, a higher intake of total and cereal fiber (g/d)/body weight (kg), a significantly lower level of plasma estrone-sulfate, estradiol, free-estradiol, free-testosterone, and ring D oxygenated estrogens, and a significantly higher level of sex-hormone-binding-globulin than BC subjects. Fiber was consumed in slightly larger amounts by omnivores than by BC subjects. Omnivores had significantly lower plasma testosterone and estrone-sulfate but higher sex-hormone-binding-globulin than BC subjects. No difference was found for the urinary 16-oxygenated estrogens. However, the 2-MeO-E1/2-OH-E1 ratio was significantly lower in omnivores than in BC group. This ratio is positively associated with the fat/fiber ratio. In conclusion, testosterone may contribute to causing alterations in the levels of catechol estrogens and 16-oxygenated estrogens. The fat/fiber ratio appears to be useful in evaluating dietary effects on estrogen metabolism.

Dietary fiber intake and risk of breast cancer: a meta-analysis of prospective cohort studies

BACKGROUND

Observational and preclinical studies suggest that dietary fiber intake may reduce the risk of breast cancer, but the results are inconclusive.

OBJECTIVE

We aimed to examine the association between dietary fiber intake and risk of breast cancer by conducting a meta-analysis of prospective cohort studies.

DESIGN

Relevant studies were identified by a PubMed database search through January 2011. Reference lists from retrieved articles were also reviewed. We included prospective cohort studies that reported RRs with 95% CIs for the association between dietary fiber intake and breast cancer risk. Both fixed- and random-effects models were used to calculate the summary risk estimates.

RESULTS

We identified 10 prospective cohort studies of dietary fiber intake and risk of breast cancer involving 16,848 cases and 712,195 participants. The combined RR of breast cancer for the highest compared with the lowest dietary fiber intake was 0.89 (95% CI: 0.83, 0.96), and little evidence of heterogeneity was observed. The association between dietary fiber intake and risk of breast cancer did not significantly differ by geographic region, length of follow-up, or menopausal status of the participants. Omission of any single study had little effect on the combined risk estimate. Dose-response analysis showed that every 10-g/d increment in dietary fiber intake was associated with a significant 7% reduction in breast cancer risk. Little evidence of publication bias was found.

CONCLUSION

This meta-analysis provides evidence of a significant inverse dose-response association between dietary fiber intake and breast cancer risk.

Plasma and urinary alkylresorcinol metabolites as potential biomarkers of breast cancer risk in Finnish women: a pilot study

Alkylresorcinols (ARs) are shown to be good biomarkers of consumption of rye and whole-grain wheat products in man. The aim of this pilot study was to investigate AR metabolites as potential biomarkers of breast cancer (BC) risk in Finnish women since intake of cereal fiber and its components has been proposed to reduce this risk through an effect on the enterohepatic circulation of estrogens. This was a cross-sectional and observational pilot study. A total of 20 omnivores, 20 vegetarians, and 16 BC women (6-12 mo after operation) were investigated on 2 occasions 6 mo apart. Dietary intake (5-days record), plasma/urinary AR metabolites [3,5-dihydroxybenzoic acid (DHBA) and 3-(3,5-dihydroxyphenyl)-1-propanoic acid (DHPPA)] and plasma/urinary enterolactone were measured. The groups were compared using nonparametric tests. We observed that plasma DHBA (P = 0.007; P = 0.03), plasma DHPPA (P = 0.02; P = 0.01), urinary DHBA (P = 0.001; P = 0.003), urinary DHPPA (P = 0.001; P = 0.001), and cereal fiber intake (P = 0.007; P = 0.003) were significantly lower in the BC group compared to the vegetarian and omnivore groups, respectively. Based on measurements of AR metabolites in urine and in plasma, whole-grain rye and wheat cereal fiber intake is low in BC subjects. Thus, urinary and plasma AR metabolites may be used as potential biomarkers of BC risk in women. This novel approach will likely also facilitate studies of associations between rye and whole-grain wheat cereal fiber intake and other diseases. Our findings should, however, be confirmed with larger subject populations.

Diet and predictors of dietary intakes in women with family history of breast and/or ovarian cancer

BACKGROUND

Dietary intakes of vegetable, fruit, fiber, folate, and B vitamins have been associated with reduced breast and/or ovarian cancer risk. However, few studies have assessed dietary intakes and factors associated with diet in women with family history of breast and/or ovarian cancer (FHBOC). We examined dietary intakes and predictors of diet in women with FHBOC (n=211) enrolled in a population-based cancer family registry.

METHODS

We assessed diet via a food frequency questionnaire, family history by telephone and demographic variables by questionnaire. Descriptive statistics were performed, and multivariate linear regression analyses were conducted to examine variables [body mass index (BMI), age, parity, energy intake, alcohol use, smoking and education] associated with dietary intakes.

RESULTS

Mean daily intakes were: 2.57 vegetable servings [+/-standard deviation (SD) 1.22], 1.56 fruit servings (+/-0.9), 11.21g fiber (+/-5.32) and 33.85% energy from fat (+/-9.05), 241.98microg folate (+/-120.80) and 1.33mg vitamin B6 (+/-0.62). Regression analyses showed that younger age, smoking, lower education and higher BMI had a significant association with decreasing vegetable, fruit and/or fiber intakes. BMI had a significant positive association with % energy from fat. Similar results were observed when assessing independent variables with micronutrient intakes studied.

CONCLUSIONS

These data suggest that women with FHBOC should be encouraged to meet dietary guidelines for cancer prevention. Specifically, public health dietary interventions should target women with FHBOC who are smokers, less educated, have a higher BMI and are younger. Such interventions may potentially reduce breast and/or ovarian cancer risk in this population.

Urinary polyphenols and breast cancer risk: results from the Shanghai Women's Health Study

Polyphenols, the most abundant dietary antioxidants, also possess many other anticarcinogenic activities. Urinary metabolites of polyphenols could complement dietary assessment of the bioavailability of these nutrients. We conducted a study of 353 incident breast cancer cases and 701 individually matched controls nested within the Shanghai Women's Health Study cohort of women aged 40-70 years at baseline. Liquid chromatography photo-diode array electrospray mass spectrometry was used to measure tea polyphenols (epicatechin, epigallocatechin, and their metabolites) and flavonols (e.g., quercetin and kaempferol). Multivariate conditional logistic regression analyses were used to assess associations between breast cancer risk and urinary excretion rates of polyphenols. Urinary excretion of tea polyphenols increased with increasing tea leaves consumed among controls, but not among breast cancer cases. Compared with cases, controls had higher levels of urinary total polyphenols and tea polyphenols, particularly epicatechin. In contrast, we did not find any dose-response relationship between urinary polyphenols and breast cancer risk. Urinary excretion of epicatechin was inversely associated with breast cancer risk [odds ratio (OR) and 95% confidence interval (CI) of 0.59 (0.39-0.88) for the intermediate tertile]. In spline regression, we found an overall dose-response relationship between epicatechin level and risk of breast cancer, although it was not apparent in low and middle urinary excretion range. In conclusion, high epicatechin may be related to a reduced risk of breast cancer. Further studies are warranted to confirm our findings.

A maternal high-fat diet during pregnancy in rats results in a greater risk of carcinogen-induced mammary tumors in the female offspring than exposure to a high-fat diet in postnatal life

The association between a high-fat diet and breast cancer risk is controversial. We hypothesized that the exposure of rats to a high-fat diet in utero via the maternal diet would result in a greater risk of carcinogen-induced mammary tumors than high-fat diet exposure in postnatal life. Rats were exposed to a high-fat diet with 40% of the energy source as safflower oil in utero (In utero group), at postnatal days 30-50 (Puberty group), postnatal days 150-170 (Adult group), postnatal days 1-230 (Postnatal group) or for their whole life from in utero (Whole group). Chow diet-fed rats were used as the Nonexposure group. Mammary tumor incidence was significantly higher in the In utero (60%), Postnatal (61%) and Whole (91%) groups than in the Nonexposure group (32%), but there was no significant difference between the Puberty (44%), Adult (44%) and Nonexposure groups. Arachidonic acid levels were 10 times higher in mammary tumor tissue than in the normal mammary gland across all groups and were positively correlated with tumor weight. We conclude that the timing, but not the duration, of high-fat diet exposure makes rats more susceptible to carcinogen-induced mammary tumors and that exposure in utero to a maternal high-fat diet during pregnancy is more important in increasing the risk of mammary tumors in the female offspring than exposure of the offspring to the same high-fat diet later in life.

Greater vegetable and fruit intake is associated with a lower risk of breast cancer among Chinese women

The effect of vegetable and fruit consumption on breast cancer risk is controversial. We examined the association between vegetable and fruit intake and breast cancer risk in a hospital-based case-control study conducted in Guangdong, China. Four hundred and thirty-eight cases were frequency matched to 438 controls by age (5-year interval) and residence (rural/urban). Dietary intake was assessed by face-to-face interviews using a validated food frequency questionnaire. Multivariate logistic regression was used to estimate the odds ratios (ORs) and 95% confidence interval (CI) after adjusting for various potential confounders. Total vegetable and fruit intake was found to be inversely associated with breast cancer risk. The ORs of the highest quartile relative to the lowest quartile of total vegetable and fruit intake were 0.28 (95% CI 0.18-0.43) and 0.53 (95% CI 0.34-0.82), respectively. Consumption of individual vegetable and fruit groups such as dark green leafy vegetables, cruciferous vegetables, carrots and tomatoes, banana, watermelon/papaya/cantaloupe were all inversely and significantly related with breast cancer risk. An inverse association was also observed for vitamin A, carotene, vitamin C, vitamin E, and fiber intake. These data indicate that greater intake of vegetables and fruits is associated with a decreased risk of breast cancer among Chinese women residing in Guangdong.

Dietary carbohydrates, fiber, and breast cancer risk in Chinese women

BACKGROUND

Few studies have investigated the association of dietary carbohydrate and fiber intake with breast cancer risk in women in China, where carbohydrate intake is traditionally high.

OBJECTIVE

The objective was to prospectively evaluate the association of dietary carbohydrates, glycemic index, glycemic load, and dietary fiber with breast cancer risk and to determine whether the effect of these dietary intakes is modified by age and selected insulin- or estrogen-related risk factors.

DESIGN

A total of 74,942 women aged 40-70 y were recruited into the Shanghai Women's Health Study, a population-based cohort study. Dietary intake was assessed by in-person interviews. A Cox proportional hazards regression model was used to evaluate associations.

RESULTS

During an average of 7.35 y of follow-up, 616 incident breast cancer cases were documented. A higher carbohydrate intake was associated with a higher risk of premenopausal breast cancer (P for trend = 0.002). Compared with the lowest quintile, the hazard ratios (and 95% CIs) were 1.47 (1.00, 2.32) and 2.01 (1.26, 3.19) for the fourth and fifth quintiles, respectively. A similar pattern was found for glycemic load. The association between carbohydrate intake and breast cancer was significantly modified by age; the increased breast cancer risk associated with carbohydrate intake was restricted to women who were younger than 50 y. No significant association of breast cancer risk with glycemic index or dietary fiber intake was found.

CONCLUSION

Our data suggest that a high carbohydrate intake and a diet with a high glycemic load may be associated with breast cancer risk in premenopausal women or women <50 y.

Vitamin supplement use and risk for breast cancer: the Shanghai Breast Cancer Study

OBJECTIVE

The influence of vitamin supplements on breast cancer risk is unclear and the interactive effects of dietary and supplemental sources are unknown. This study investigated (1) the association between self-reported vitamin supplement use (multivitamin, A, B, C, and E) and breast cancer and (2) the combined effect of vitamin supplements in relation to dietary vitamin intakes on breast cancer risk.

METHODS

The Shanghai Breast Cancer Study was a population-based case-control study conducted in Shanghai in 1996-1998 (Phase I) and 2002-2004 (Phase II). Participants were aged 25-64 (Phase I) and 20-70 years (Phase II). The analyses included 3,454 incident breast cancer cases and 3,474 controls. Unconditional logistic regression models were used to determine adjusted odds ratios (ORs) for breast cancer risk associated with vitamin supplement use.

RESULTS

Overall, breast cancer risk was not related to any vitamin supplement intake. However, a 20% reduction in breast cancer risk was observed with vitamin E supplement use among women with low-dietary vitamin E intake (OR = 0.8; 95% confidence interval (CI), 0.6-1.0). A non-significant 20% risk reduction was observed among vitamin B supplement users with low B dietary intake (OR = 0.8; 95% CI, 0.6-1.1). Frequent use of a vitamin B supplement was adversely associated with breast cancer risk among those with high dietary vitamin B intake (OR = 1.4; 95% CI: 0.9-2.1; P for interaction = 0.07).

CONCLUSIONS

This study suggests that vitamins E and B supplements may confer protection against breast cancer among women who have low dietary intake of those vitamins.

Information Needs of Women At Risk of Breast Cancer

Purpose: Information needs and current information sources related to healthy eating, active living, and healthy body weight were examined in women attending breast cancer risk assessment clinics.

Methods: Convenience sampling was used to recruit 257 women over 20 years old. The women completed a selfadministered survey (52.8% response rate) containing both closed- and open-ended questions. Most respondents were 49 or younger, were English-speaking, reported annual family incomes over $140,000, and resided in urban communities.

Results: Participants reported a need for general information concerning healthy eating, active living, and healthy body weight. For example, they wanted information on reading food labels (51.0%), healthy recipes (51.0%), activities for increasing overall fitness (52.5%), and achieving healthy body weights (48.6%). They also wanted information concerning the relationships between cancer risk and specific foods and nutrients, such as antioxidants (65.0%), supplements (60.7%), phytochemicals (47.5%), and omega-3 fatty acids (45.5%). Participants most often turned to magazines, friends, and family members when they wanted information on healthy eating, active living, and healthy body weight.

Conclusions: These findings present an opportunity for dietitians to enhance their leadership role in creating and disseminating evidence-based information to meet the expressed needs of women who may be at increased risk for breast cancer.