Fruits, Vegetables, and Micronutrients in Relation to Breast Cancer Modified by Menopause and Hormone Receptor Status

Active Molecular Network Discovery Links Lifestyle Variables to Breast Cancer in the Long Island Breast Cancer Study Project

A healthy lifestyle has been associated with decreased risk of developing breast cancer. Using untargeted metabolomics profiling, which provides unbiased information regarding lifestyle choices such as diet and exercise, we aim to identify the molecular mechanisms connecting lifestyle and breast cancer through network analysis. A total of 100 postmenopausal women, 50 with breast cancer and 50 cancer-free controls, were selected from the Long Island Breast Cancer Study Project (LIBCSP). We measured untargeted plasma metabolomics using liquid chromatography-high-resolution mass spectrometry (LC-HRMS). Using the "enet" package, we retained highly correlated metabolites representing active molecular network (AMN) clusters for analysis. LASSO was used to examine associations between cancer status and AMN metabolites and covariates such as BMI, age, and reproductive factors. LASSO was then repeated to examine associations between AMN metabolites and 10 lifestyle-related variables including smoking, physical activity, alcohol consumption, meat consumption, fruit and vegetable consumption, and supplemental vitamin use. Results were displayed as a network to uncover biological pathways linking lifestyle factors to breast cancer status. After filtering, 851 "active" metabolites out of 1797 metabolomics were retained in 197 correlation AMN clusters. Using LASSO, breast cancer status was associated with 71 "active" metabolites. Several of these metabolites were associated with lifestyle variables including meat consumption, alcohol consumption, and supplemental β-carotene, B12, and folate use. Those metabolites could potentially serve as molecular-level biological intermediaries connecting healthy lifestyle factors to breast cancer, even though direct associations between breast cancer and the investigated lifestyles at the phenotype level are not evident. In particular, DiHODE, a metabolite linked with inflammation, was associated with breast cancer status and connected to β-carotene supplement usage through an AMN. We found several plasma metabolites associated with lifestyle factors and breast cancer status. Future studies investigating the mechanistic role of inflammation in linking supplement usage to breast cancer status are warranted.

Barriers to consumption of fruits and vegetables and strategies to overcome them in low- and middle-income countries: a narrative review

This review provides an overview of the barriers to the consumption of fruits and vegetables (FVs) as well as strategies to improve the intake of FVs in low- and middle-income countries (LMICs). The importance of the consumption of FVs and its role in disease prevention are discussed briefly. Trends in the consumption of FVs in LMICs are also summarised. The WHO recommends that every individual should consume at least five servings or 400 grams of FVs per day. Epidemiological and clinical investigations have demonstrated that FVs contain numerous bioactive compounds with health-protecting activities. Despite their health benefits, the intake of FVs in LMICs remains low. Major barriers identified were socio-demographic factors, environmental conditions, individual and cultural factors, and macrosystem influences. These barriers may be lowered at the household, school, community, and national level through multi-component interventions including behaviour change communication (BCC) initiatives, nutrition education (NE), gardening initiatives, farm to institution programs (FIPs), food baskets, cash transfers, nutrition-agriculture policy and program linkages, and food-market environment-based strategies. This review has research implications due to the positive outcomes of strategies that lower such barriers and boost consumption of FVs in LMICs.

Personalized breast cancer onset prediction from lifestyle and health history information

We propose a method to predict when a woman will develop breast cancer (BCa) from her lifestyle and health history features. To address this objective, we use data from the Alberta's Tomorrow Project of 18,288 women to train Individual Survival Distribution (ISD) models to predict an individual's Breast-Cancer-Onset (BCaO) probability curve. We show that our three-step approach-(1) filling missing data with multiple imputations by chained equations, followed by (2) feature selection with the multivariate Cox method, and finally, (3) using MTLR to learn an ISD model-produced the model with the smallest L1-Hinge loss among all calibrated models with comparable C-index. We also identified 7 actionable lifestyle features that a woman can modify and illustrate how this model can predict the quantitative effects of those changes-suggesting how much each will potentially extend her BCa-free time. We anticipate this approach could be used to identify appropriate interventions for individuals with a higher likelihood of developing BCa in their lifetime.

Association of Fruit, Vegetable, and Animal Food Intakes with Breast Cancer Risk Overall and by Molecular Subtype among Vietnamese Women

BACKGROUND

Evidence on associations between dietary intake and risk of breast cancer subtypes is limited and inconsistent. We evaluated associations of fruit, vegetable, meat, and fish consumption with risk of breast cancer overall and by molecular subtype in the Vietnamese Breast Cancer Study (VBCS).

METHOD

VBCS includes 476 incident breast cancer cases and 454 age-matched controls. Dietary habits over the past 5 years were assessed by in-person interviews using a validated food frequency questionnaire. Associations of food groups with breast cancer were evaluated via logistic regression for overall and molecular subtype with adjustment for age, education, income, family history of cancer, menopausal status, body mass index, exercise, total energy intake, and other potential dietary confounders. Odds ratio (OR) was used to approximate relative risk.

RESULTS

High fruit intake was inversely associated with breast cancer risk, with adjusted ORs [95% confidence intervals (CI)] of 0.67 (95% CI, 0.47-0.95) and 0.41 (95% CI, 0.27-0.61) for second and third tertiles versus first tertile, respectively (Ptrend < 0.001). This association was stronger for triple-negative than other subtypes (Pheterogeneity < 0.001). High intake of freshwater fish was inversely associated with overall breast cancer (ORT3vsT1 = 0.63; 95% CI, 0.42-0.95; Ptrend = 0.03). An inverse association was observed between HER2-enriched subtype and red and organ meat intake (ORT3vsT1 = 0.40; 95% CI, 0.17-0.93; Ptrend = 0.04; Pheterogeneity = 0.50).

CONCLUSIONS

High intakes of fruit and freshwater fish were associated with reduced breast cancer risk; association for the former was stronger for triple-negative subtype.

IMPACT

Our findings suggest high intakes of fruit and freshwater fish may reduce breast cancer risk among Vietnamese women.

Healthy dietary patterns and risk and survival of breast cancer: a meta-analysis of cohort studies

PURPOSES

Dietary patterns have been found to be associated with the overall cancer risk and survival. However, the associations of healthy dietary patterns and breast cancer remain unclear. We aimed to conduct a meta-analysis of prospective cohort studies to estimate the pooled results of the association of healthy dietary patterns with breast cancer risk and survival.

METHODS

PubMed, EMBASE, and Web of Science were searched for literature published until June 24th, 2018 that examined the associations between healthy dietary patterns and breast cancer risk and survival. Risk ratios (RRs) and 95% confidence intervals (CIs) were calculated by using a random-effects model for meta-analysis.

RESULTS

There were 32 articles retrieved for the meta-analysis, with 27 for breast cancer risk and five for breast cancer survival. There was a statistically significant lower risk of breast cancer associated with healthy dietary patterns (RR = 0.93, 95% CI: 0.88, 0.98). Subgroup analysis results suggested that there was an inverse association between breast cancer risk and posterori-derived healthy patterns, but no statistically significant associations were found in other stratified subgroups (a priori-derived diet, study region, menopausal status, or breast cancer subtypes). Healthy dietary patterns were associated inversely with all-cause mortality (RR = 0.76, 95% CI: 0.63, 0.92); however, no association was found for breast cancer-specific mortality.

CONCLUSIONS

The results suggested that healthy dietary patterns might be associated with a reduced risk of breast cancer and all-cause mortality among breast cancer patients. It could be clinically relevant to promote healthy dietary patterns for breast cancer prevention and improve survival among breast cancer patients.

The Role of Food Antioxidants, Benefits of Functional Foods, and Influence of Feeding Habits on the Health of the Older Person: An Overview

This overview was directed towards understanding the relationship of brain functions with dietary choices mainly by older humans. This included food color, flavor, and aroma, as they relate to dietary sufficiency or the association of antioxidants with neurodegenerative diseases such as dementia and Alzheimer’s disease. Impairment of olfactory and gustatory function in relation to these diseases was also explored. The role of functional foods was considered as a potential treatment of dementia and Alzheimer’s disease through inhibition of acetylcholinesterase as well as similar treatments based on herbs, spices and antioxidants therein. The importance of antioxidants for maintaining the physiological functions of liver, kidney, digestive system, and prevention of cardiovascular diseases and cancer has also been highlighted. Detailed discussion was focused on health promotion of the older person through the frequency and patterns of dietary intake, and a human ecology framework to estimate adverse risk factors for health. Finally, the role of the food industry, mass media, and apps were explored for today’s new older person generation.

Patterns of change over time and history of the inflammatory potential of diet and risk of breast cancer among postmenopausal women

We utilized the dietary inflammatory index (DII) to investigate associations between patterns of change in, and history of the inflammatory potential of diet and risk of breast cancer in the Women's Health Initiative (WHI). We included 70,998 postmenopausal women aged 50-79 years recruited from 1993 to 1998 into the WHI Observational Study and Dietary Modification trial control group and followed through August 29, 2014. We utilized data from food frequency questionnaires administered at baseline and Year 3, to calculate average DII scores, patterns of change in DII, and used these measures in multivariable-adjusted Cox regression models to estimate hazards ratios (HR) and 95 % confidence intervals (CI) for incident invasive breast cancer and its subtypes. After 1,093,947 person-years of follow-up, 3471 cases of invasive breast cancer were identified. There was no substantial association between average DII scores or patterns of change in DII and risk of overall invasive breast cancer (HR, 1.03; 95 % CI, 0.90, 1.17; P-trend = 0.79; comparing extreme average DII quintiles). However, there was a significant nonlinear association between average DII scores and the ER-, PR-, HER2+, subtype (HR, 2.37; 95 % CI, 1.08, 5.20; P-trend = 0.18; comparing extreme quintiles). For patterns of change in DII, the age-adjusted association with ER-, PR-, HER2+ subtype comparing women in the proinflammatory stable to those in the anti-inflammatory stable categories (HR, 1.82; 95 % CI, 1.06, 3.13) persisted in the multivariable-adjusted model but was less precise (HR, 1.85; 95 % CI, 0.96, 3.55; P = 0.06). Dietary inflammatory potential may differentially influence the development of specific breast cancer phenotypes.

GST polymorphism and excretion of heterocyclic aromatic amine and isothiocyanate metabolites after Brassica consumption

Brassica vegetable intake has been associated with decreased risk and well-done meat intake has been associated with increased risk of cancers at multiple organ sites in epidemiologic studies. Experimental studies suggest a role of modulation of phase I and phase II metabolizing enzymes as one mechanism for these associations. Heterocyclic aromatic amines (HAAs) are carcinogens formed in meat that has been cooked to well-done and at high temperatures. Phase I metabolizing enzymes catalyze the activation of HAAs, and phase II metabolizing enzymes serve to detoxify the active carcinogens. The glutathione S-transferases (GSTs) are a family of phase II metabolizing enzymes that are induced by, and act to conjugate, isothiocyanates (ITCs), phytochemicals found in Brassica vegetables. This review summarizes the results of feeding studies in humans that examine effects of polymorphisms in GSTs on ITC metabolite excretion, reviews the evidence for modulation of HAA mutagenicity by ITCs, and discusses the need for feeding studies examining potential interactions among polymorphic genes encoding phase I and phase II metabolizing enzymes, meat intake, and Brassica intake to elucidate their role in cancer etiology.

Polycyclic aromatic hydrocarbon-DNA adducts and survival among women with breast cancer

Polycyclic aromatic hydrocarbons (PAH) are mammary carcinogens in animal studies, and a few epidemiologic studies have suggested a link between elevated levels of PAH-DNA adducts and breast cancer incidence. An association between PAH-DNA adducts and survival among breast cancer cases has not been previously reported. We conducted a survival analysis among women with newly diagnosed invasive breast cancer between 1996 and 1997, enrolled in the Long Island Breast Cancer Study Project. DNA was isolated from blood samples that were obtained from cases shortly after diagnosis and assayed for PAH-DNA adducts using ELISA. Among the 722 cases with PAH-DNA adduct measurements, 97 deaths (13.4%) from all causes and 54 deaths (7.5%) due to breast cancer were reported to the National Death Index (NDI) by December 31, 2002. Using Cox proportional hazards models and controlling for age at diagnosis, we did not find evidence that all-cause mortality (hazard ratio (HR)=0.88; 95% confidence interval (CI): 0.57-1.37), or breast cancer mortality (HR=1.20; 95% CI: 0.63-2.28) was strongly associated with detectable PAH-DNA adduct levels compared with non-detectable adducts; additionally, no dose-response association was observed. Among a subgroup with treatment data (n=520), adducts were associated with over a two-fold higher mortality among those receiving radiation, but mortality for adducts was reduced among hormone therapy users. Results from this large population-based study do not provide strong support for an association between detectable PAH-DNA adducts and survival among women with breast cancer, except perhaps among those receiving radiation treatment.

Dietary flavonoid intake and breast cancer survival among women on Long Island

BACKGROUND

Laboratory research and a growing number of epidemiologic studies have provided evidence for a reduced risk of breast cancer associated with dietary intake of certain classes of flavonoids. However, the effects of flavonoids on survival are not known. In a population-based cohort of breast cancer patients, we investigated whether dietary flavonoid intake before diagnosis is associated with subsequent survival.

METHODS

Women ages 25 to 98 years who were newly diagnosed with a first primary invasive breast cancer between August 1, 1996, and July 31, 1997, and participated in a population-based, case-control study (n=1,210) were followed for vital status through December 31, 2002. At the case-control interview conducted shortly after diagnosis, respondents completed a FFQ that assessed dietary intake in the previous 12 months. All-cause mortality (n=173 deaths) and breast cancer-specific mortality (n=113 deaths) were determined through the National Death Index.

RESULTS

Reduced hazard ratios [age- and energy-adjusted hazard ratio (95% confidence interval)] for all-cause mortality were observed among premenopausal and postmenopausal women for the highest quintile of intake, compared with the lowest, for flavones [0.63 (0.41-0.96)], isoflavones [0.52 (0.33-0.82)], and anthocyanidins [0.64 (0.42-0.98)]. No significant trends in risk were observed. Results were similar for breast cancer-specific mortality only.

CONCLUSION

Mortality may be reduced in association with high levels of dietary flavones and isoflavones among postmenopausal U.S. breast cancer patients. Larger studies are needed to confirm our findings.

Carbohydrate intake, glycemic index, glycemic load, and risk of postmenopausal breast cancer in a prospective study of French women

BACKGROUND

Diets high in carbohydrates may result in chronically elevated insulin concentrations and may affect breast cancer risk by stimulation of insulin receptors or through insulin-like growth factor I (IGF-I)-mediated mitogenesis. Insulin response to carbohydrate intake is increased in insulin-resistant states such as obesity.

OBJECTIVE

We sought to evaluate carbohydrate intake, glycemic index (GI), and glycemic load (GL) and subsequent overall and hormone-receptor-defined breast cancer risk among postmenopausal women.

DESIGN

A prospective cohort analysis of dietary carbohydrate and fiber intakes was conducted among 62 739 postmenopausal women from the E3N French study who had completed a validated dietary history questionnaire in 1993. During a 9-y period, 1812 cases of pathology-confirmed breast cancer were documented through follow-up questionnaires. Nutrients were categorized into quartiles and energy-adjusted with the regression-residual method. Cox model-derived relative risks (RRs) were adjusted for known determinants in breast cancer.

RESULTS

Dietary carbohydrate and fiber intakes were not associated with overall breast cancer risk. Among overweight women, we observed an association between GI and breast cancer (RR(Q1-Q4): 1.35; 95% CI: 1.00, 1.82; P for trend = 0.04). For women in the highest category of waist circumference, the RR(Q1-Q4) was 1.28 (95% CI: 0.98, 1.67; P for trend = 0.10) for carbohydrates, 1.35 (95% CI: 1.04, 1.75; P for trend = 0.01) for GI, and 1.37 (95% CI: 1.05, 1.77; P for trend = 0.003) for GL. We also observed a direct association between carbohydrate intake, GL, and estrogen receptor-negative breast cancer risk.

CONCLUSIONS

Rapidly absorbed carbohydrates are associated with postmenopausal breast cancer risk among overweight women and women with large waist circumference. Carbohydrate intake may also be associated with estrogen receptor-negative breast cancer.

Selected antioxidants and risk of hormone receptor-defined invasive breast cancers among postmenopausal women in the Women's Health Initiative Observational Study

BACKGROUND

Few studies have evaluated carotenoids and vitamins C and E in association with the risk of breast cancers defined by estrogen receptor (ER) and progesterone receptor (PR) status.

OBJECTIVE

We examined the associations between dietary and supplemental intakes of these nutrients and risk of breast cancers jointly defined by both ER and PR status among postmenopausal women.

DESIGN

Our investigation was conducted in the Women's Health Initiative Observational Study. After following 84 805 women for an average of 7.6 y, 2879 incident invasive breast cancer cases had been ascertained, of whom 2509 had receptor data. We used Cox proportional hazards models to assess the associations of interest.

RESULTS

Dietary alpha-carotene (highest versus lowest quintile: RR = 0.83; 95% CL = 0.70, 0.99; P for trend = 0.019), beta-carotene (highest versus lowest quintile: RR = 0.78; 95% CL = 0.66, 0.94; P for trend = 0.021), and lycopene (highest versus lowest quintile: RR = 0.85; 95% CL = 0.73, 1.00; P for trend = 0.064) were inversely associated with risk of ER+PR+breast cancer, but not with other breast cancer groups jointly defined by ER and PR status. Total or supplemental beta-carotene and dietary intakes of lutein+zeaxanthin and beta-cryptoxanthin were not associated with breast cancers defined by ER and PR status. Vitamin E (regardless of source) and dietary vitamin C were not associated with breast cancer. However, total and supplemental vitamin C intake had weak positive associations with breast cancer overall.

CONCLUSION

Dietary intake of certain carotenoids might be differentially associated with risk of invasive breast cancers jointly defined by ER and PR status among postmenopausal women.

Whole-food sources of vitamin A more effectively inhibit female rat sexual maturation, mammary gland development, and mammary carcinogenesis than retinyl palmitate

Previous work using an adolescent rat model for breast cancer showed increased tumor occurrence in rats fed a chemopreventive dose of vitamin A. Preclinical models for nutrient-cancer interactions utilizing defined diets do not replicate the complexity of the human diet and may be inadequate to investigate food patterns associated with reduced cancer risk in humans. To evaluate this concept, the effects of vitamin A on sexual maturation, mammary gland development, and sensitivity to carcinogenesis were determined in the context of a human food-based diet (whole food diet). At 20 d of age (p20), female rats received either a whole-food diet with adequate levels of vitamin A, a diet with a 5.5-fold increase in vitamin A from fruits and vegetables (S diet), or a diet with a 6.2-fold increase in vitamin A provided as retinyl palmitate (RP diet). To determine the effect of dietary intervention on pubertal mammary gland development, the dietary intervention period was restricted to postnatal d 21-63. Rats were injected with 50 mg 1-methyl-1-nitrosourea/kg body weight at d 66. Compared with adolescent rats that consumed the Ad diet, consumption of S and RP diets reduced mammary cancer multiplicity (relative risk approximately 0.7, P < or = 0.002), which was associated with a reduction in alveolar gland development. The S diet suppressed the onset of sexual maturation (P < 0.001) and inhibited markers of mammary alveologenesis more than the RP diet. These data demonstrate that the amount and source of vitamin A consumed by adolescent female rats can influence the onset of puberty, mammary gland alveolar development, and breast cancer risk and highlight the relevance of utilizing whole-food diets to evaluate the role of dietary factors in cancer prevention.

A functional 19-base pair deletion polymorphism of dihydrofolate reductase (DHFR) and risk of breast cancer in multivitamin users

BACKGROUND

Dihydrofolate reductase (DHFR) converts dihydrofolate (DHF) into tetrahydrofolate (THF) and plays an essential role in cell metabolism and cellular growth. Folic acid from multivitamins needs to be reduced by DHFR before it participates in cellular reactions.

OBJECTIVES

We examined the relation of a 19-base pair (bp) deletion polymorphism of the DHFR gene with the risk of breast cancer by using data from the Long Island Breast Cancer Study Project, a population-based case-control study. We also investigated the transcriptional effect of this deletion polymorphism.

DESIGN

Dietary data and habitual use of multivitamins were assessed from a modified Block food-frequency questionnaire (FFQ). Genotypes of DHFR were ascertained from 1062 case subjects and 1099 control subjects by allele-specific polymerase chain reaction. Unconditional logistic regression was used to estimate odds ratios (ORs) and 95% CIs.

RESULT

Although the DHFR 19-bp deletion polymorphism was not associated with overall breast cancer risk, we observed a borderline significant additive interaction (P = 0.06) between the DHFR genotype and multivitamin use. The -19-bp allele was associated with greater breast cancer risk in multivitamin users (51.2% of the study population) with an OR of 1.26 (95% CI: 0.96, 1.66) and 1.52 (95% CI: 1.08, 2.13) for the +/- and -/- genotypes, respectively (P for trend = 0.02) than in multivatimin nonusers. A dose-dependent relation (P for trend < 0.001) between DHFR expression and the deletion genotype was observed. Compared with the subjects with the 19-bp +/+ genotype, subjects with the -/- genotype had 4.8-fold DHFR mRNA levels.

CONCLUSIONS

The DHFR 19-bp deletion polymorphism affects the transcription of DHFR gene in humans. Multivitamin supplements may place a subgroup of women (ie, those with the -19-bp allele) at elevated risk of developing breast cancer.

Relationship between urinary 15-F2t-isoprostane and 8-oxodeoxyguanosine levels and breast cancer risk

To evaluate the role of oxidative stress in breast cancer, we measured urinary levels of 15-F(2t)-isoprostane (15-F(2t)-IsoP) and 8-oxodeoxyguanosine (8-oxodG) in 400 cases and 401 controls, participants of the Long Island Breast Cancer Study Project. We also analyzed the effect of different factors that are associated with oxidative stress and might influence 15-F(2t)-IsoP and 8-oxodG levels. We observed a statistically significant trend in breast cancer risk with increasing quartiles of 15-F(2t)-IsoP levels [odds ratio (OR), 1.25; 95% confidence interval (95% CI), 0.81-1.94; OR, 1.53; 95% CI, 0.99-2.35; OR, 1.88; 95% CI, 1.23-2.88, for the 2nd, 3rd, and 4th quartile relative to the lowest quartile, respectively; P(trend) = 0.002]. Although it is possible that increased levels may reflect the stress associated with recent treatment, the positive association was also observed when the analyses were restricted to case women for whom chemotherapy and radiation therapy had not yet been initiated at the time of the urine collection. The association with the highest quartile compared with lowest quartile of 15-F(2t)-IsoP was similar across strata of age, physical activity, fruit and vegetable intake, alcohol intake, cigarette smoking, body mass index, and menopausal status. We did not observe any association of breast cancer risk with 8-oxodG levels, but when cases with radiation treatment were removed from the analysis, a significant inverse trend (P = 0.04) was observed. Among controls, levels of 15-F(2t)-IsoP were higher among current cigarette smokers but did not differ by the amount of physical activity, fruit and vegetable intake, alcohol intake, body mass index, and menopausal status. Among controls, levels of 8-oxodG were higher among postmenopausal women and current and former cigarette smokers but did not differ by the other factors. In summary, our results suggest that urinary markers of lipid peroxidation and oxidative DNA damage may be associated with breast cancer risk.

OGG1 polymorphisms and breast cancer risk

The role of oxidative stress in breast cancer risk is still unclear. OGG1 encodes an 8-oxoguanine DNA glycosylase/AP lyase that catalyzes the removal of 8-oxodeoxyguanosine from DNA. 8-Oxodeoxyguanosine, the most abundant lesion generated by oxidative stress, is highly mutagenic. Environmental sources of oxidative stress, such as alcohol consumption, cigarette smoking, high body mass index (BMI), and low fruits and vegetables intake, may modify the association of genetic polymorphisms with breast cancer risk. We investigated the association between three genetic polymorphisms in OGG1 (Ser(326)Cys, 7143A/G, and 11657A/G) and breast cancer risk among 1,058 cases and 1,102 controls participating in the Long Island Breast Cancer Study Project. No associations were observed between individual OGG1 polymorphisms, haplotypes, or diplotypes and breast cancer. The association between having at least one variant allele and breast cancer risk was stronger among moderate alcohol drinkers for Ser(326)Cys [odds ratio (OR), 1.82; 95% confidence interval (95% CI), 1.06-3.10] relative to nondrinkers with the wild-type genotype and among those with higher BMI for 7143A/G (OR, 1.47; 95% CI, 1.10-1.96) and for 11657A/G (OR, 1.41; 95% CI, 1.05-1.88), relative to women with BMI < 25 kg/m(2) and the wild-type genotype. However, the patterns were not seen for all three single nucleotide polymorphisms (SNP) nor were there any clear allele dose associations; only one interaction was statistically significant, assuming a multiplicative model (11657A/G, P(interaction) = 0.04). In summary, although we found some differences between the three OGG1 SNPs and breast cancer risk among moderate alcohol drinkers and women with higher BMI, replication of these results is needed to rule out spurious findings. In addition, data on functionality of these polymorphisms are crucial to understand if these modest differences are important.

Folate, vitamin B(6), and vitamin B(12) intake and the risk of breast cancer among Mexican women

BACKGROUND

High intake of folate, vitamin B(6), and vitamin B(12) have been hypothesized to lower the risk for breast cancer. We conducted a population-based case-control study to evaluate the risk for breast cancer among Mexican women with relatively low vitamin intakes.

METHODS

We included 475 women (median age, 53 years; range, 23-87 years) diagnosed with incident breast cancer through six hospitals in Mexico City and interviewed them to obtain data on breast cancer risk factors and their usual diet using a food frequency questionnaire. We selected 1,391 (median age, 49 years; range, 18-82 years) controls from the Mexico City population using a national sampling frame.

RESULTS

Compared with women in the lowest quartile, the odds ratio for breast cancer for women in the highest quartile of folate intake was 0.64 [95% confidence intervals (CI), 0.45-0.90; P, test for trend = 0.009] and 0.32 (95% CI, 0.22-0.49; P, test for trend < 0.0001) for vitamin B(12) intake. Among postmenopausal women, intakes of folate and vitamin B(12) were associated with a lower risk of breast cancer and those associations were stronger than among premenopausal women. The inverse association of folate and breast cancer was stronger among women who consumed a high level of vitamin B(12) as compared with women consuming diets low in vitamin B(12). No association was observed for vitamin B(6) intake.

CONCLUSIONS

In this population, high intakes of folate and vitamin B(12) were independently associated with decreased breast cancer risk, particularly among postmenopausal women.

Empirically derived dietary patterns and risk of postmenopausal breast cancer in a large prospective cohort study

BACKGROUND

Inconsistent associations have been reported between diet and breast cancer.

OBJECTIVE

We prospectively examined the association between dietary patterns and postmenopausal breast cancer risk in a US-wide cohort study.

DESIGN

Data were analyzed from 40 559 women who completed a self-administered 61-item Block food-frequency questionnaire in the Breast Cancer Detection Demonstration Project, 1987-1998; 1868 of those women developed breast cancer. Dietary patterns were defined by using principal components factor analysis. Cox proportional hazard regression was used to assess breast cancer risk.

RESULTS

Three major dietary patterns emerged: vegetable-fish/poultry-fruit, beef/pork-starch, and traditional southern. The vegetable-fish/poultry-fruit pattern was associated with higher education than were the other patterns, but was similar in nutrient intake to the traditional southern pattern. After adjustment for confounders, there was no significant association between the vegetable-fish/poultry-fruit and beef/pork-starch patterns and breast cancer. The traditional southern pattern, however, was associated with a nonsignificantly reduced breast cancer risk among all cases (in situ and invasive) that was significant for invasive breast cancer (relative hazard = 0.78; 95% CI = 0.65, 0.95; P for trend = 0.003). This diet was also associated with a reduced risk in women without a family history of breast cancer (P = 0.05), who were underweight or normal weight [body mass index (in kg/m(2)) < 25; P = 0.02], or who had tumors positive for estrogen receptor (P = 0.01) or progesterone receptor (P = 0.003). Foods in the traditional southern pattern associated with reduced breast cancer risk were legumes, low mayonnaise-salad dressing intake, and possibly cabbage.

CONCLUSIONS

The traditional southern diet or its components are associated with a reduced risk of invasive breast cancer in postmenopausal women.

One-Carbon Metabolism,MTHFRPolymorphisms, and Risk of Breast Cancer

Accumulating evidence from epidemiologic studies suggests that risk of breast cancer is reduced in relation to increased consumption of folate and related B vitamins. We investigated independent and joint effects of B vitamin intake as well as two polymorphisms of a key one-carbon metabolizing gene [i.e., methylenetetrahydrofolate reductase (MTHFR) 677C>T and 1298A>C] on breast cancer risk. The study uses the resources of a population-based case-control study, which includes 1,481 cases and 1,518 controls. Significant inverse associations between B vitamin intake and breast cancer risk were observed among non-supplement users. The greatest reduction in breast cancer risk was observed among non-supplement users in the highest quintile of dietary folate intake [odds ratio (OR), 0.61; 95% confidence interval (95% CI), 0.41-0.93] as compared with non-supplement users in the lowest quintile of dietary folate intake (high-risk individuals). The MTHFR 677T variant allele was associated with increased risk of breast cancer (P, trend = 0.03) with a multivariate-adjusted OR of 1.37 (95% CI, 1.06-1.78) for the 677TT genotype. The 1298C variant allele was inversely associated with breast cancer risk (P, trend = 0.03), and was likely due to the linkage of this allele to the low-risk allele of 677C. The MTHFR-breast cancer associations were more prominent among women who did not use multivitamin supplements. Compared with 677CC individuals with high folate intake, elevation of breast cancer risk was most pronounced among 677TT women who consumed the lowest levels of dietary folate (OR, 1.83; 95% CI, 1.13-2.96) or total folate intake (OR, 1.71; 95% CI, 1.08-2.71). From a public heath perspective, it is important to identify risk factors, such as low B vitamin consumption, that may guide an effective prevention strategy against the disease.

Polymorphisms in XRCC1 Modify the Association between Polycyclic Aromatic Hydrocarbon-DNA Adducts, Cigarette Smoking, Dietary Antioxidants, and Breast Cancer Risk

The variability in DNA repair capacity of the general population may depend in part upon common variants in DNA repair genes. X-ray repair cross complementing group 1 (XRCC1) is an important DNA base excision repair gene and exhibits polymorphic variation. Using the Long Island Breast Cancer Study Project, a population-based case-control study, we evaluated the hypothesis that two common single nucleotide polymorphisms of XRCC1 (codon 194 Arg-->Trp and 399 Arg-->Gln) influence breast cancer susceptibility and interact with polycyclic aromatic hydrocarbon (PAH)-DNA adducts, cigarette smoking, and intake of fruits and vegetables and antioxidants. The available sample for genotyping included 1,067 cases and 1,110 controls. Genotyping was done by a high-throughput single-nucleotide extension assay with fluorescence polarization detection of the incorporated nucleotide. We observed no significant increases in risk among all subjects who were carriers of XRCC1 194Trp or 399Gln alleles. Among never smokers, we observed an increased risk of breast cancer in 399Gln carriers [odds ratio (OR), 1.3; 95% confidence interval (CI), 1.0-1.7). Further analysis indicated a suggestive weak additive interaction between the 399Gln allele and detectable PAH-DNA adducts (OR for exposure with mutant genotype, 1.9; 95% CI, 1.2-3.1). The estimated age-adjusted interaction contrast ratio (ICR) and 95% CI (ICR, 0.38; 95% CI, -0.32 to 1.10) indicated that the departure from additivity was not statistically significant, but that there was some suggestion of a relative excess risk due to the interaction. In subjects with at least one copy of XRCC1 194Trp allele, there was a moderate interaction with high intake of fruits and vegetables (>/=35 half-cup servings per week of any fruits, fruit juices, and vegetables, OR, 0.58; 95% CI, 0.38-0.89; ICR, -0.49; 95% CI, -0.03 to -0.95), and dietary plus supplement antioxidant intake with 33% to 42% decreases in breast cancer risk compared with those with the Arg194Arg genotype and low-intake individuals. These results do not show that the two genetic polymorphisms of XRCC1 independently influence breast cancer risk. However, there is evidence for interactions between the two XRCC1 single nucleotide polymorphisms and PAH-DNA adducts or fruit and vegetable and antioxidant intake on breast cancer risk. Further understanding of the biological function of XRCC1 variants and their interactions with PAH-DNA adducts, antioxidants, and other genes in the pathway are needed.

Myeloperoxidase Genotype, Fruit and Vegetable Consumption, and Breast Cancer Risk

Myeloperoxidase (MPO), an antimicrobial enzyme in the breast, generates reactive oxygen species (ROS) endogenously. An MPO G463A polymorphism exists in the promoter region, with the variant A allele conferring lower transcription activity than the common G allele. Because oxidative stress may play a role in breast carcinogenesis, we evaluated MPO genotypes in relation to breast cancer risk among 1,011 cases and 1,067 controls from the Long Island Breast Cancer Study Project (1996-1997). We also assessed the potential modifying effects of dietary antioxidants and hormonally related risk factors on these relationships. Women over 20 years with incident breast cancer who were residents of Nassau and Suffolk Counties, NY, were identified as potential cases. Population-based controls were frequency matched by 5-year age groups. Genotyping was performed with matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF) technology, and suspected breast cancer risk factors and usual dietary intake were assessed during an in-person interview. Unconditional logistic regression was used to estimate odds ratios and 95% confidence intervals. Having at least one A allele was associated with an overall 13% reduction in breast cancer risk. When consumption of fruits and vegetables and specific dietary antioxidants were dichotomized at the median, inverse associations with either GA or AA genotypes were most pronounced among women who consumed higher amounts of total fruits and vegetables (odds ratio, 0.75; 95% confidence interval, 0.58-0.97); this association was not noted among the low-consumption group (P for interaction = 0.04). Relationships were strongest among premenopausal women. Results from this first study of MPO genotypes and breast cancer risk indicate that MPO variants, related to reduced generation of ROS, are associated with decreased breast cancer risk, and emphasize the importance of fruit and vegetable consumption in reduction of breast cancer risk.