Nutritional epidemiology of postmenopausal breast cancer in western New York

Investigation of the Association between Drinking Water Habits and the Occurrence of Women Breast Cancer

Risk and protective factors for breast cancer (BC) include lifestyle, diet, reproduction, and others. Increased risk for colon cancer was linked with low water intake. The link between water consumption and BC was scarcely studied. We investigated the association between water and fluid consumption and the occurrence of BC in a retrospective case-control study in the Shaare Zedek Medical Center, Jerusalem, in 206 women aged 25-65 years (106 with newly diagnosed BC, and 100 controls). A food frequency questionnaire (FFQ), consumption of water, foods, and beverages, lifestyle, and other risk and protective factors were recorded. The age of women in both groups was comparable ((M ± SD) 52.7 ± 9.8 and 50.6 ± 11.4 years, respectively (p = 0.29)). Women with BC consumed 20.2% less water (M ± SD = 5.28 ± 4.2 and 6.62 ± 4.5 cups/day, respectively, p = 0.02) and 14% less total fluids than controls (M ± SD = 2095 ± 937 mL/day and 2431 ± 1087 mL/day, respectively, p = 0.018). Multiple stepwise logistic regression showed that the differences remained significant both for daily water consumption (p = 0.031, CI = 0.462-0.964) and for total daily liquid intake (p = 0.029, CI = 0.938-0.997). Low water and liquids intake as a risk factor for BC may be related to the younger age of our subjects. The effect of age on the potential role of water intake in decreasing BC risk should be investigated.

Availability and Utilization of Pigments from Microalgae

Microalgae are the major photosynthesizers on earth and produce important pigments that include chlorophyll a, b and c, β-carotene, astaxanthin, xanthophylls, and phycobiliproteins. Presently, synthetic colorants are used in food, cosmetic, nutraceutical, and pharmaceutical industries. However, due to problems associated with the harmful effects of synthetic colorants, exploitation of microalgal pigments as a source of natural colors becomes an attractive option. There are various factors such as nutrient availability, salinity, pH, temperature, light wavelength, and light intensity that affect pigment production in microalgae. This paper reviews the availability and characteristics of microalgal pigments, factors affecting pigment production, and the application of pigments produced from microalgae. The potential of microalgal pigments as a source of natural colors is enormous as an alternative to synthetic coloring agents, which has limited applications due to regulatory practice for health reasons.

Meta-Analysis of Saturated Fatty Acid Intake and Breast Cancer Risk

The associations between saturated fatty acid (SFA) consumption and risk of breast cancer (BC) remains inconclusive. Therefore, we conducted this meta-analysis to determine the quantitative relations between dietary SFA intake and incidence of BC.Literatures published up to April 2015 were systematically screened through Pubmed and Web of Science. Relevant publication quality was evaluated by conducting the Newcastle-Ottawa scale. We used fixed effects models or random effect models to calculate the summary relative risks (RRs) and odds ratios (ORs), and conducted sensitivity analyses and evaluated the publication bias.We identified a total of 52 studies (24 cohort studies and 28 case-control studies), with over 50,000 females diagnosed with BC. The associations between dietary SFA intake and risk of BC were 1.18 for case-control studies (high vs low intake, 95% confidence interval [CI] = 1.03-1.34) and 1.04 for cohort studies (95% CI = 0.97-1.11). When restricted analyses to population-based studies, positive associations were observed for both cohort (RR [95% CI] = 1.11 [1.01-1.21]) and case-control studies (OR [95% CI] = 1.26 [1.03-1.53]). Additionally, for case-control studies, significant positive associations between higher SFA intake and BC risk were observed for Asian (OR [95% CI] = 1.17 [1.02-1.34]) and Caucasian (OR [95% CI] = 1.19 [1.00-1.41]), as well as for postmenopausal women (OR = 1.33, 95% CI: 1.02-1.73). In contrast, higher dietary SFA intake was not associated with risk of BC among premenopausal women, in cohort studies or hospital-based studies.A positive association between higher dietary SFA intake and postmenopausal BC risk was observed in case-control but not in cohort studies. More studies are warranted to confirm these findings.

Folate intake and the risk of breast cancer: a systematic review and meta-analysis

There is conflicting epidemiological evidence on the role of folate and breast cancer risk. We conducted a systematic review and quantitative meta-analysis of folate intake and folate blood levels and the risk of breast cancer. Four electronic databases (Medline, PubMed, Embase, and Current Contents Connect) were searched to April 11, 2014, with no language restrictions for observational studies that measured folate intake or blood levels and the risk of breast cancer. The meta-analysis of dietary folate intake comprising 36 studies with 34,602 cases, and a total sample size of 608,265 showed a decreased risk of breast cancer, with an odds ratio (OR) of 0.84 [95 % confidence interval (CI) 0.77-0.91]. When stratified by menopausal status and by study design, none of the meta-analyses of prospective studies showed any statistically significant decrease in the risk of breast cancer. The meta-analysis of total folate showed no statistically significant association with breast cancer OR of 0.98 (95 % CI 0.91-1.07). There was no significant association between either dietary or total folate intake and breast cancer when stratified by hormonal receptor status. The meta-analysis of blood folate levels found no significant association with the risk of breast cancer, with an OR of 0.86 (95 % CI 0.60-1.25). Breast cancer does not appear to be associated with folate intake, and this did not vary by menopausal status or hormonal receptor status. Folate blood levels also do not appear to be associated with breast cancer risk.

Higher dietary folate intake reduces the breast cancer risk: a systematic review and meta-analysis

Background:

Many epidemiological studies have investigated the association between folate intake, circulating folate level and risk of breast cancer; however, the findings were inconsistent between the studies.

Methods:

We searched the PubMed and MEDLINE databases updated to January, 2014 and performed the systematic review and meta-analysis of the published epidemiological studies to assess the associations between folate intake level, circulating folate level and the overall risk of breast cancer.

Results:

In all, 16 eligible prospective studies with a total of 744 068 participants and 26 205 breast cancer patients and 26 case–control studies with a total of 16 826 cases and 21 820 controls that have evaluated the association between folate intake and breast cancer risk were identified. Pooled analysis of the prospective studies and case–control studies suggested a potential nonlinearity relationship for dietary folate intake and breast cancer risk. Prospective studies indicated a U-shaped relationship for the dietary folate intake and breast cancer risk. Women with daily dietary folate intake between 153 and 400 μg showed a significant reduced breast cancer risk compared with those <153 μg, but not for those >400 μg. The case–control studies also suggested a significantly negative correlation between the dietary folate intake level and the breast cancer risk. Increased dietary folate intake reduced breast cancer risk for women with higher alcohol intake level, but not for those with lower alcohol intake. No significant association between circulating folate level and breast cancer risk was found when the results of 8 identified studies with 5924 participants were pooled.

Conclusions:

Our studies suggested that folate may have preventive effects against breast cancer risk, especially for those with higher alcohol consumption level; however, the dose and timing are critical and more studies are warranted to further elucidate the questions.

Total energy intake and breast cancer risk in sisters: the Breast Cancer Family Registry

Energy restriction inhibits mammary tumor development in animal models. Epidemiologic studies in humans generally do not support an association between dietary energy intake and breast cancer risk, although some studies suggest a more complex interplay between measures of energy intake, physical activity, and body size. We examined the association between total energy intake jointly with physical activity and body mass index (BMI) and the risk of breast cancer among 1,775 women diagnosed with breast cancer between 1995 and 2006 and 2,529 of their unaffected sisters, enrolled in the Breast Cancer Family Registry. We collected dietary data using the Hawaii-Los Angeles Multiethnic Cohort food frequency questionnaire. Using conditional logistic regression to estimate the odds ratios (OR) and 95 % confidence intervals (CI) associated with total energy intake, we observed an overall 60-70 % increased risk of breast cancer among women in the highest quartile of total energy intake compared to those in the lowest quartile (Q4 vs. Q1: OR = 1.6, 95 % CI: 1.3-2.0; P (trend) < 0.0001); these associations were limited to pre-menopausal women or women with hormone receptor-positive cancers. Although the associations were slightly stronger among women with a higher BMI or lower level of average lifetime physical activity, we observed a positive association between total energy intake and breast cancer risk across different strata of physical activity and BMI. Our results suggest that within sisters, high energy intake may increase the risk of breast cancer independent of physical activity and body size. If replicated in prospective studies, then these findings suggest that reductions in total energy intake may help in modifying breast cancer risk.

Association of overweight and obesity with breast cancer in India

Background:

In women, cancer of the breast is one of the most common incident cancer and cause of death from cancer. Anthropometric factors of weight, height, and body mass index (BMI) have been associated with breast cancer risk.

Objectives:

To study the association of overweight and obesity with breast cancer in India.

Materials and Methods:

A hospital-based matched case-control study was conducted. Three hundred and twenty newly diagnosed breast cancer patients and three hundred and twenty normal healthy individuals constituted the study population. The subjects in the control group were matched individually with the patients for their age ±2 years and socioeconomic status. Anthropometric measurements of weight and height were recorded utilizing the standard equipments and methodology. The paired ‘t’ test and univariate logistic regression analysis were carried out.

Results:

It was observed that the patients had a statistically higher mean weight, body mass index, and mid upper arm circumference as compared to the controls. It was observed that the risk of breast cancer increased with increasing levels of BMI. Overweight and obese women had Odd's redio of 1.06 and 2.27, respectively, as compared to women with normal weight.

Conclusions:

The results of the present study revealed a strong association of overweight and obesity with breast cancer in the Indian population.

Retinol, vitamins A, C, and E and breast cancer risk: a meta-analysis and meta-regression

OBJECTIVE

To comprehensively summarize the associations between retinol, vitamins A, C, and E and breast cancer, and quantitatively estimate their dose-response relationships.

METHODS

We searched PubMed, Embase, and Cochrane databases (from January 1982 to 15 March 2011) and the references of the relevant articles in English with sufficient information to estimate relative risk or odds ratio and the 95% confidence intervals, and comparable categories of vitamins. Two reviewers independently extracted data using a standardized form, with any discrepancy adjudicated by the third reviewer.

RESULTS

Overall, 51 studies met the inclusion criteria. Comparing the highest with the lowest intake, total vitamin A intake reduced the breast cancer risk by 17% (pooled OR = 0.83, 95% CI: 0.78-0.88). Further subgroup analysis based on study design did not change the significant reduction. Although the dietary vitamin A, dietary vitamin E, and total vitamin E intake all reduced breast cancer risk significantly when data from all studies were pooled, the results became nonsignificant when data from cohort studies were pooled. The significant association between total retinol intake and breast cancer in all studies became nonsignificant in case-control studies but remain significant in cohort studies. No significant dose-response relationship was observed in the higher intake of these vitamins with reduced breast cancer risk.

CONCLUSIONS

Our results indicate that both the total intake of vitamin A and retinol could reduce breast cancer risk. However, associations between other vitamins and breast cancer seem to be limited.

Dietary folate, vitamin B6, vitamin B12 and methionine intake and the risk of breast cancer by oestrogen and progesterone receptor status

Few studies have evaluated the relationship between the consumption of dietary folate and one-carbon metabolism-related nutrients and breast cancer risk defined by oestrogen receptor (ER) and progesterone receptor (PR) status. The objective of the present study was to examine the associations between dietary folate, vitamin B6, vitamin B12, and methionine intake and the risk of breast cancer by ER and PR status among Chinese women in Guangdong. A hospital-based case–control study was conducted from June 2007 to August 2008, with 438 cases and 438 age (5-year interval)- and residence (rural/urban)-matched controls. Dietary intake information was assessed using a validated FFQ administered through a face-to-face interview. Unconditional logistic regression models were used to calculate multivariate-adjusted OR and 95 % CI. A significant inverse association was found between dietary folate and vitamin B6 intake and breast cancer risk. The adjusted OR of the highest v. the lowest quartile were 0·32 (95 % CI 0·21, 0·49; Ptrend < 0·001) for dietary folate and 0·46 (95 % CI 0·30, 0·69; Ptrend < 0·001) for vitamin B6. No associations were observed for vitamin B12 and methionine intake. A significant inverse association between dietary folate intake and breast cancer risk was observed in all subtypes of ER and PR status. These findings suggest that dietary folate and vitamin B6 intakes were inversely associated with breast cancer risk. The inverse association did not differ by ER and/or PR status.

Hyperhomocysteinemia and the role of B vitamins in cancer

BACKGROUND

Patients suffering from malignancies have increased complications due to corresponding cardiovascular diseases and risk factor for the development of venous thromboembolism. Epidemiological studies have shown that increased homocysteine plasma concentration (hyperhomocysteinemia) is related to a higher risk of coronary heart disease, stroke, peripheral vascular disease and malignancies. Homocysteine (tHcy) is an intermediate sulfur-containing amino acid produced from methionine during processing of dietary proteins. The plasma homocysteine levels are strongly influenced by diet, as well as by genetic factors. Folic acid, vitamins B6 and B12 are dietary components which influence the plasma homocysteine levels the most. Several studies have found that high blood levels of B vitamins are related to the integrity and function of DNA, and, are at least related to lower concentration of homocysteine. Folate depletion has been found to change DNA methylation and DNA synthesis in both animal and human studies. Because of this critical role of folate, most studies including homocysteine have focused on these two actions.

CONCLUSIONS

Hyperhomocysteinemia proves to be the most common condition highly associated with both venous and arterial thrombosis in many cancer patients, while the associated pathophysiology has not been precisely established yet. Therefore, of current interest is the possible role of folate metabolism developing into a cancer initiating hyperhomocysteinemia. This review will discuss this possibility.

Dietary carotenoids and the risk of invasive breast cancer

Certain classes of vitamins and nutrients found in fruits and vegetables have been of particular interest in relation to cancer prevention, owing to their potential anticarcinogenic properties. We examined the association between certain fruits, vegetables, carotenoids, and vitamin A and breast cancer risk in a large population-based case-control study of women residing in the states of Massachusetts, New Hampshire and Wisconsin. The study was comprised of 5,707 women with incident invasive breast cancer (2,363 premenopausal women and 3,516 postmenopausal women) and 6,389 population controls (2,594 premenopausal women and 3,516 postmenopausal women). In an interview, women were asked about their intake of carotenoid rich fruits and vegetables 5 years prior to a referent date. An inverse association observed among premenopausal women was for high levels of vitamin A (OR: 0.82, 95% CI: 0.68-0.98, p for trend = 0.01), beta-carotene (OR: 0.81, 95% CI 0.68-0.98, p for trend = 0.009), alpha-carotene (OR: 0.82, 95% CI: 0.68-0.98, p for trend = 0.07) and lutein/zeaxanthin (OR: 0.83, 95% CI 0.68-0.99, p for trend = 0.02). An inverse association was not observed among postmenopausal women. Among premenopausal women who reported ever smoking, these results were stronger than among never smokers, although tests for interaction were not statistically significant. Results from this study are comparable to previous prospective studies, and suggest that a high consumption of carotenoids may reduce the risk of premenopausal but not postmenopausal breast cancer, particularly among smokers.

Folate and one-carbon metabolism nutrients from supplements and diet in relation to breast cancer risk

BACKGROUND

Few epidemiologic studies have examined very high intakes of folate and whether consumption of nutrients involved in one-carbon metabolism is associated with breast cancer risk.

OBJECTIVE

We prospectively examined whether the consumption of folate and nutrients involved in one-carbon metabolism (methionine, riboflavin, and vitamins B-6 and B-12) from self-reported intakes of diet (in year before baseline) and supplements (averaged over 10 y before baseline) were associated with the incidence of breast cancer and breast cancer tumor characteristics.

DESIGN

Participants were 35,023 postmenopausal women aged 50-76 y in the VITamins And Lifestyle (VITAL) cohort study; breast cancer was diagnosed in 743 of these women between baseline (2000-2002) and 2006. Cox proportional hazards models were used to estimate multivariable-adjusted relative risks (RRs) and 95% CIs.

RESULTS

Women consuming > or =1272 dietary folate equivalents (DFE)/d of total folate (10-y average) had a 22% decrease in breast cancer risk compared with women consuming < or =345 DFE/d (RR: 0.78; 95% CI: 0.61, 0.99; P for trend = 0.05). A greater benefit was observed for estrogen-receptor (ER) negative than for ER+ breast cancers (RR: 0.38; 95% CI: 0.18, 0.80; P for trend = 0.02; P = 0.02 for the difference between ER- and ER+). Neither current intakes of folate nor current or long-term intakes of other one-carbon nutrients were significantly associated with breast cancer risk. Multivitamin use attenuated the increased risk of breast cancer associated with alcohol drinking (P for interaction = 0.02).

CONCLUSIONS

Our study of predominantly supplement users suggests that high intakes of folate averaged over 10 y do not increase breast cancer risk, but may be protective, particularly against ER- breast cancers.

Energy intake, physical activity, energy balance, and cancer: epidemiologic evidence

Energy intake, physical activity, and obesity are modifiable lifestyle factors. This chapter reviews and summarizes the epidemiologic evidence on the relation of energy intake, physical activity, and obesity to cancer. High energy intake may increase the risk of cancers of colon-rectum, prostate (especially advanced prostate cancer), and breast. However, because physical activity, body size, and metabolic efficiency are highly related to total energy intake and expenditure, it is difficult to assess the independent effect of energy intake on cancer risk. There are sufficient evidences to support a role of physical activity in preventing cancers of the colon and breast, whereas the association is stronger in men than in women for colon cancer and in postmenopausal than in premenopausal women for breast cancer. The evidence also suggests that physical activity likely reduces the risk of cancers of endometrium, lung, and prostate (to a lesser extent). On the other hand, there is little or no evidence that the risk of rectal cancer is related to physical activity, whereas the results have been inconsistent regarding the association between physical activity and the risks of cancers of pancreas, ovary and kidney. Epidemiologic studies provide sufficient evidence that obesity is a risk factor for both cancer incidence and mortality. The evidence supports strong links of obesity with the risk of cancers of the colon, rectum, breast (in postmenopausal women), endometrium, kidney (renal cell), and adenocarcinoma of the esophagus. Epidemiologic evidence also indicates that obesity is probably related to cancers of the pancreas, liver, and gallbladder, and aggressive prostate cancer, while it seems that obesity is not associated with lung cancer. The role of obesity in other cancer risks is unclear.

Vitamin D receptor polymorphisms (FokI, BsmI) and breast cancer risk: association replication in two case-control studies within French Canadian population

Vitamin D has been associated with reduced breast cancer risk. We studied the association of two vitamin D receptor (VDR) gene single nucleotide polymorphisms restriction enzyme detecting SNP of VDR (FokI and BsmI) with breast cancer risk in two independent case-control studies carried out in the same population. The modifying effect of family history of breast cancer on this relationship was also evaluated. The first and second studies included respectively 718 (255 cases/463 controls) and 1596 (622 cases/974 controls) women recruited in Quebec City, Canada. FokI and BsmI genotypes were assessed. Relative risks of breast cancer were estimated by multivariate logistic regression. Compared with homozygotes for the common F allele (FF genotype), FokI ff homozygotes had a higher breast cancer risk (study 1: odds ratio (OR)=1.22, 95% confidence interval (CI)=0.76-1.95; study 2: OR=1.44, 95% CI=1.05-1.99; and combined studies: OR=1.33, 95% CI=1.03-1.73). Significant interactions were observed between FokI and family history of breast cancer in the two studies as well as in the combined analysis (P interaction=0.031, 0.050 and 0.0059 respectively). Among women without family history, odds ratios were 1.00, 1.27 (95% CI=1.02-1.58) and 1.57 (95% CI=1.18-2.10) respectively for FF, Ff and ff carriers (P(trend)=0.0013). BsmI Bb+bb genotypes were associated with a weak non-significant increased risk in the two studies (combined OR=1.22, 95% CI=0.95-1.57) without interaction with family history. Results support the idea that vitamin D, through its signalling pathway, can affect breast cancer risk. They also suggest that variability in observed associations between VDR FokI and breast cancer from different studies may partly be explained by the proportion of study subjects with a family history of breast cancer.

Caffeine consumption and the risk of breast cancer in a large prospective cohort of women

BACKGROUND

Prospective data relating caffeine consumption to breast cancer risk are limited.

METHODS

We evaluated the association between caffeine consumption and breast cancer risk in women enrolled in a completed cancer prevention trial. Detailed dietary information was obtained at baseline (1992-1995) from 38 432 women 45 years or older and free of cancer. During a mean follow-up of 10 years, we identified 1188 invasive breast cancer cases.

RESULTS

Consumption of caffeine and caffeinated beverages and foods was not statistically significantly associated with overall risk of breast cancer. The multivariate relative risks (RRs) of breast cancer were 1.02 (95% confidence interval [CI], 0.84-1.22) for caffeine (top vs bottom quintile), 1.08 (0.89-1.30) for coffee (> or =4 cups daily vs almost never), and 1.03 (0.85-1.25) for tea (> or =2 cups daily vs almost never). However, in women with benign breast disease, a borderline significant positive association with breast cancer risk was observed for the highest quintile of caffeine consumption (RR, 1.32; 95% CI, 0.99-1.76) and for the highest category of coffee consumption (> or =4 cups daily) (1.35; 1.01-1.80); tests for interaction were marginally significant. Caffeine consumption was also significantly positively associated with risk of estrogen receptor-negative and progesterone receptor-negative breast cancer (RR, 1.68; 95% CI, 1.01-2.81) and breast tumors larger than 2 cm (1.79; 1.18-2.72).

CONCLUSIONS

These data show no overall association between caffeine consumption and breast cancer risk. The possibility of increased risk in women with benign breast disease or for tumors that are estrogen and progesterone receptor negative or larger than 2 cm warrants further study.

Tonsillectomy and breast cancer risk in the Western New York Diet Study

OBJECTIVES

Exposures during early life may affect risk of breast cancer. History of tonsillectomy has recently been associated with risk of several cancers, including cancer of the breast.

METHODS

We conducted a population-based case-control study of women living in Western New York from 1986 to 1991. Cases had incident, primary, pathologically confirmed breast cancer and were recruited through all major hospitals in the region (n = 740). Population-based controls (n = 810) were randomly sampled from among drivers' license holders from Department of Motor Vehicles records (<65 yrs) and from Health Care Finance Administration records (> or =65 yrs). Participants were interviewed with regard to diet, anthropometrics, demographics, medical, and reproductive history. Unconditional logistic regression models stratified by menopausal status were used to estimate multivariate odds ratios (OR) and 95% confidence intervals (95% CI).

RESULTS

A history of tonsillectomy was associated with increased breast cancer risk among premenopausal (OR 1.50, 95% CI: 1.08-2.08) but not postmenopausal women (OR 1.05, 95% CI: 0.79-1.38).

CONCLUSIONS

Our findings add to accumulating data implicating tonsillectomy in risk of cancer. Tonsillectomy may be an indicator for conditions of chronic inflammation and/or reduced efficiency of immune function. Our study also provides additional evidence that early life exposures may affect premenopausal breast cancer risk.

State ranks of incident cancer burden due to overweight and obesity in the United States, 2003

OBJECTIVE

Given links between obesity and cancer, we estimated incident cancer burden due to overweight and obesity at the state level in the United States.

METHODS AND PROCEDURES

Using state rankings by per capita burden of incident cancer cases diagnosed in 2003 that were related to overweight and obesity, we examined the frequency with which states ranked in the highest and lowest quintiles of weight-related burden for cancers of the postmenopausal breast, endometrium, kidney, colon, and prostate. In this study, data from the Behavioral Risk Factor Surveillance System (BRFSS), US Census, US Mortality Public Use Data Tapes, and National Cancer Institute Surveillance, Epidemiology, and End Results (SEER) Program were used.

RESULTS

Western states had the lowest weight-related cancer burden for both sexes. Iowa, South Dakota, and West Virginia had the highest burden for all three types of male cancers. West Virginia is the only state that ranked in the quintile of highest weight-related burden for all four cancers considered in women.

DISCUSSION

For certain cancers, including endometrial, postmenopausal breast, and colon cancers, states with high burdens clustered in geographic regions, warranting further inquiry. Although state ranks for the total cancer burden and the prevalence of overweight and obesity correlated with state ranks for weight-related incident cancer burden, they often served poorly as its proxy. Such a finding cautions against simply targeting states with high overweight and obesity or high total burdens of cancers for which overweight and obesity are risk factors, as this approach may not reach areas of unrecognized burden.

Measures of adiposity and body fat distribution in relation to serum folate levels in postmenopausal women in a feeding study

OBJECTIVE

To assess the associations between serum folate concentration and measures of adiposity in postmenopausal women.

DESIGN

This study was conducted as a cross-sectional analysis within the control segment of a randomized, crossover trial in which postmenopausal women (n=51) consumed 0 g (control), 15 g (one drink) and 30 g (two drinks) alcohol (ethanol)/day for 8 weeks as part of a controlled diet. Subjects in one treatment arm were crossed-over to another arm after a 2- to 5-week washout period. Body mass index (BMI) was measured, and dual energy X-ray absorptiometry (DEXA) scan administered to the women during the control (0 g alcohol) treatment, and a blood sample from this group was collected at baseline and week 8 of each diet period and analyzed for folate, B12, homocysteine and methylmalonic acid.

SETTING

This study was conducted at the Beltsville Human Nutrition Research Center, MD, USA.

RESULTS

In multivariate analysis, women who were overweight had a 12% lower, and obese women had a 22% lower serum folate concentrations compared to normal weight women (P-trend=0.02). Vitamin B12 also decreased with increasing BMI (P-trend=0.08). Increased BMI, percent body fat, and absolute amounts of central and peripheral fat were all significantly associated with decreased serum folate, but were unrelated to serum B12, homocysteine or methylmalonic acid.

CONCLUSIONS

Our data show that adiposity is associated with lower serum folate levels in postmenopausal women. With obesity at epidemic proportions, these data, if confirmed by prospective or randomized controlled studies, have important public health implications.

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.

Plasma folate, vitamin B-6, vitamin B-12, and risk of breast cancer in women

BACKGROUND

B vitamins such as folate, vitamin B-6, and vitamin B-12 are coenzymes that are important for DNA integrity and stability. Deficiency in these B vitamins may promote tumor carcinogenesis.

OBJECTIVE

We prospectively evaluated plasma concentrations of folate, pyridoxal 5-phosphate (PLP; the principal active form of vitamin B-6), and vitamin B-12 in relation to breast cancer risk.

DESIGN

We included 848 incident cases of invasive breast cancer identified as of 31 March 2004, and 848 individually matched control subjects from 28 345 women in the Women's Health Study aged > or =45 y who provided blood samples and had no history of cancer and cardiovascular disease at baseline in 1993. Logistic regression controlling for matching factors and other risk factors for breast cancer was used to estimate relative risks (RRs) and 95% CIs. All statistical tests were 2 sided.

RESULTS

Plasma concentrations of folate, PLP, and vitamin B-12 were not associated with overall risk of breast cancer. Women in the highest quintile group relative to those in the lowest quintile had multivariate RRs of 1.42 (95% CI: 1.00, 2.02) for plasma folate (P for trend = 0.21), 0.91 (95% CI: 0.63, 1.30) for plasma PLP (P for trend = 0.48), and 1.29 (95% CI: 0.92, 1.82) for plasma vitamin B-12 (P for trend = 0.18). However, higher plasma folate concentrations were moderately associated with an increased risk of developing premenopausal breast cancer (P for trend = 0.04) and for developing estrogen receptor (ER)-positive or progesterone receptor (PR)-positive breast tumors (P for trend < or = 0.06). Conversely, an inverse association was seen between plasma PLP and postmenopausal breast cancer (P for trend = 0.04).

CONCLUSIONS

Data from this study suggest that B vitamins, including folate, vitamin B-6, and vitamin B-12, may confer little or no reduction in overall risk of developing breast cancer. The observed positive associations of folate status with risk of developing premenopausal breast cancer and ER-positive or PR-positive tumors are unexpected. Additional research is needed to elucidate the role of folate in breast cancer development.

Increasing folate supplementation for selected groups of Canadian women

After review of current evidence related to the potential risks and benefits of folic acid supplementation, we conclude that unless clinicians can be assured that pregnant women will reliably use prenatal vitamin supplements containing 0.8-1.1 mg of folate, the prenatal vitamin supplements should be combined with 5 mg of folate.

Dietary fiber intake and risk of postmenopausal breast cancer defined by estrogen and progesterone receptor status-A prospective cohort study among Swedish women

There is few data on the association between dietary fiber intake and estrogen receptor (ER)/progesterone receptor (PR)-defined breast cancer risk. We evaluated the association between dietary fiber and ER/PR-defined breast cancer risk stratified by postmenopausal hormone use, alcohol intake, and family history of breast cancer in the population-based Swedish Mammography Screening Cohort comprising 51,823 postmenopausal women. Fiber intake was measured by food-frequency questionnaire collected in 1987 and 1997. Relative risks (RRs) were estimated by hazard ratio derived from Cox proportional hazard regression models. During an average of 8.3-year follow-up, 1,188 breast cancer cases with known ER/PR status were diagnosed. When comparing the highest to the lowest quintile, we observed non-significant inverse associations between total fiber intake and the risk of all tumor subtypes; the multivariate-adjusted RRs were 0.85 (95% CI: 0.69-1.05) for overall, 0.85 (0.64-1.13) for ER+PR+, 0.83 (0.52-1.31) for ER+PR- and 0.94 (0.49-1.80) for ER-PR-. For specific fiber, we observed statistically significant risk reductions for overall (34%) and for ER+PR+ (38%) for the highest versus lowest quintile of fruit fiber, and non-significant inverse associations for other subtypes of cancer and types of fiber. Among ever-users of postmenopausal hormone (PMH), total fiber intake and especially cereal fiber were statistically significantly associated with approximately 50% reduced risk for overall and ER+PR+ tumors when comparing the highest to the lowest quartile, but no association was observed among PMH never users. Our results suggest that dietary fiber intake from fruit and cereal may play a role in reducing breast cancer risk.

High folate intake is associated with lower breast cancer incidence in postmenopausal women in the Malmö Diet and Cancer cohort

BACKGROUND

Epidemiologic studies of associations between folate intake and breast cancer are inconclusive, but folate and other plant food nutrients appear protective in women at elevated risk.

OBJECTIVE

The objective was to examine the association between folate intake and the incidence of postmenopausal breast cancer.

DESIGN

This prospective study included all women aged >or=50 y (n = 11699) from the Malmö Diet and Cancer cohort. The mean follow-up time was 9.5 y. We used a modified diet-history method to collect nutrient intake data. At the end of follow-up, 392 incident invasive breast cancer cases were verified. We used proportional hazard regression to calculate hazard ratios (HRs).

RESULTS

Compared with the lowest quintile, the incidence of invasive breast cancer was reduced in the highest quintile of dietary folate intake (HR: 0.56; 95% CI: 0.35, 0.90; P for trend = 0.02); total folate intake, including supplements (HR: 0.56; 95% CI: 0.34, 0.91; P for trend = 0.006); and dietary folate equivalents (HR: 0.59; 95% CI: 0.36, 0.97; P for trend = 0.01).

CONCLUSION

A high folate intake was associated with a lower incidence of postmenopausal breast cancer in this cohort.

The U.S. Food and Drug Administration's evidence-based review for qualified health claims: tomatoes, lycopene, and cancer

Several studies have reported an inverse association between tomato and/or lycopene intake and the risk of some types of cancer. In 2004, the U.S. Food and Drug Administration (FDA) received two petitions for qualified health claims regarding tomatoes, lycopene, and the risk reduction for some forms of cancer. Health claims that characterize the relationship between a food or food component and a disease or health-related condition require premarket approval by FDA to be included on the labels of conventional foods and dietary supplements. Here we describe FDA's review of the scientific data for tomato and/or lycopene intake with respect to risk reduction for certain forms of cancer. The FDA found no credible evidence to support an association between lycopene intake and a reduced risk of prostate, lung, colorectal, gastric, breast, ovarian, endometrial, or pancreatic cancer. The FDA also found no credible evidence for an association between tomato consumption and a reduced risk of lung, colorectal, breast, cervical, or endometrial cancer. The FDA found very limited evidence to support an association between tomato consumption and reduced risks of prostate, ovarian, gastric, and pancreatic cancers.

Folate and risk of breast cancer: a meta-analysis

BACKGROUND

Epidemiologic findings are inconsistent concerning risk for breast cancer associated with low folate intake or blood folate levels. We performed a meta-analysis of prospective and case-control studies to examine folate intake and levels in relation to risk of breast cancer.

METHODS

We searched MEDLINE for studies of this association that were published in any language from January 1, 1966, through November 1, 2006. Study-specific risk estimates were pooled by use of a random-effects model. All statistical tests were two-sided.

RESULTS

Folate intake in increments of 200 microg/day was not associated with the risk of breast cancer in prospective studies (estimated summary relative risk [RR] = 0.97, 95% confidence interval [CI] = 0.88 to 1.07, for dietary folate [eight studies; 302,959 participants and 8367 patients with breast cancer], and RR = 1.01, 95% CI = 0.97 to 1.05, for total folate [six studies; 306,209 participants and 8165 patients with breast cancer]) but was statistically significantly inversely associated with risk in case-control studies (estimated summary odds ratio [OR] = 0.80, 95% CI = 0.72 to 0.89, for dietary folate [13 studies; 8558 case patients and 10,812 control subjects], and OR = 0.93, 95% CI = 0.81 to 1.07, for total folate [three studies; 2184 case patients and 3233 control subjects]). High blood folate levels versus low levels were not statistically significantly associated with the risk of breast cancer in prospective studies (OR = 0.81, 95% CI = 0.59 to 1.10 [three studies]) or in case-control studies (OR = 0.41, 95% CI = 0.15 to 1.10 [two studies]). Among the two prospective studies and two case-control studies that stratified by alcohol consumption, high folate intake (comparing the highest with the lowest category) was associated with a statistically significant decreased risk of breast cancer among women with moderate or high alcohol consumption (summary estimate = 0.51, 95% CI = 0.41 to 0.63) but not among women with low or no alcohol consumption (summary estimate = 0.95, 95% CI = 0.78 to 1.15). Few studies examined whether the relation between folate intake and breast cancer was modified by intakes of methionine or vitamins B6 and B12, and the findings were inconsistent.

CONCLUSION

No clear support for an overall relationship between folate intake or blood folate levels and breast cancer risk was found. Adequate folate intake may reduce the increased risk of breast cancer that has been associated with moderate or high alcohol consumption.

Diet and breast cancer

Clarification of the role of diet in breast cancer pathogenesis is important in order to identify modifiable risk factors on which to focus prevention efforts. Excess weight and weight gain in adult life are related to higher risk of postmenopausal breast cancer, and weight loss after menopause is associated with substantially reduced risk. Even moderate alcohol consumption contributes considerably to excess breast cancer risk, which can likely be mitigated with adequate folate intake. Diet during early life may play a substantial role in later cancer risk, but data are limited. In addition, physical activity and the prevention of weight gain can improve survival after a breast cancer diagnosis.

Meta-analyses of Observational and Genetic Association Studies of Folate Intakes or Levels and Breast Cancer Risk

BACKGROUND

Evidence from case-control studies suggests that increasing dietary folate intake is associated with a reduced risk of breast cancer. However, large cohort studies have found no such association, and animal studies suggest that folate supplementation may promote tumorigenesis. We conducted a meta-analysis to summarize the available evidence from observational studies on this issue and a meta-analysis of the association between a common polymorphism in the 5,10-methylenetetrahydrofolate reductase (MTHFR) gene, a key enzyme in folate metabolism, and breast cancer risk.

METHODS

We searched Medline and ISI Web of Knowledge databases for relevant studies that were published through May 31, 2006. We used random-effects analysis to calculate odds ratios (ORs) for case-control studies or relative risks (RRs) for cohort studies for a 100-microg/d increase in folate intake. Unadjusted odds ratios were calculated for the studies of MTHFR genotype based on published genotype frequencies.

RESULTS

A total of 13 case-control studies and nine cohort studies were included in the meta-analysis of folate intake and breast cancer risk. We found a summary OR of 0.91 (95% confidence interval [CI] = 0.87 to 0.96) from the case-control studies and a summary RR of 0.99 (95% CI = 0.98 to 1.01) from the cohort studies for a 100-microg/d increase in folate intake. We found evidence that the case-control studies may have suffered from substantial publication bias. The case-control and cohort studies may have been subject to measurement error, confounding, and possibly spurious associations arising from subgroup analyses; in addition, the case-control studies were potentially subject to recall bias and publication bias. Seventeen studies were included in the meta-analysis of MTHFR C677T genotype and breast cancer risk. We found no difference in breast cancer risk between MTHFR 677 TT homozygotes and CC homozygotes (OR = 1.05, 95% CI = 0.88 to 1.25), and there was no evidence of an interaction between folate intake and MTHFR genotype on breast cancer risk.

CONCLUSION

A lack of dietary folate intake is not associated with the risk of breast cancer.

Commonly studied single-nucleotide polymorphisms and breast cancer: results from the Breast Cancer Association Consortium

BACKGROUND

The Breast Cancer Association Consortium (BCAC) is an international collaboration that was established to provide large sample sizes for examining genetic associations. We conducted combined analyses on all single-nucleotide polymorphisms (SNPs) whose associations with breast cancer have been investigated by at least three participating groups.

METHODS

Data from up to 12 studies were pooled for each SNP (ADH1C I350V, AURKA F31I, BRCA2 N372H, CASP8 D302H, ERCC2 D312N, IGFBP3 -202 c>a, LIG4 D501D, PGR V660L, SOD2 V16A, TGFB1 L10P, TP53 R72P, XRCC1 R399Q, XRCC2 R188H, XRCC3 T241M, XRCC3 5' UTR, and XRCC3 IVS7-14). Genotype frequencies in case and control subjects were compared, and genotype-specific odds ratios for the risk of breast cancer in heterozygotes and homozygotes for the rare allele compared with homozygotes for the common allele were estimated with logistic regression. Statistical tests were two-sided.

RESULTS

The total number of subjects for analysis of each SNP ranged from 12,013 to 31,595. For five SNPs--CASP8 D302H, IGFBP3 -202 c>a, PGR V660L, SOD2 V16A, and TGFB1 L10P--the associations with breast cancer were of borderline statistical significance (P = .016, .060, .047, .056, and .0088 respectively). The remaining 11 SNPs were not associated with breast cancer risk; genotype-specific odds ratios were close to unity. There was some evidence for between-study heterogeneity (P<.05) for four of the 11 SNPs (ADH1C I350V, ERCC2 D312N, XRCC1 R399Q, and XRCC3 IVS5-14).

CONCLUSION

Pooling data within a large consortium has helped to clarify associations of SNPs with breast cancer. In the future, consortia such as the BCAC will be important in the analysis of rare polymorphisms and gene x gene or gene x environment interactions, for which individual studies have low power to identify associations, and in the validation of associations identified from genome-wide association studies.

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.

Association of energy intake and energy balance with postmenopausal breast cancer in the prostate, lung, colorectal, and ovarian cancer screening trial

Energy restriction remains one of the most effective ways known to prevent breast cancer in animal models. However, energy intake has not been consistently associated with risk of breast cancer in humans. In a prospective study, we assessed whether energy intake, body size, and physical activity each independently influence breast cancer risk in postmenopausal women and estimated the joint effect of combinations of these individual factors. As part of the Prostate, Lung, Colorectal, and Ovarian Cancer Screening Trial, 38,660 women, ages 55 to 74 years and recruited from 10 centers in the United States during 1993 to 2001, were randomized to the screening arm of the trial. At baseline, the women completed a self-administered questionnaire, including a food frequency questionnaire. During follow-up from 1993 to 2003, 764 incident breast cancer cases were ascertained. Women in the highest quartile of energy intake (> or = 2,084 kcal/d) compared with those in the lowest quartile (<1,316 kcal/d) had a significantly increased risk for breast cancer [multivariate relative risk (RR), 1.25; 95% confidence interval (95% CI), 1.02-1.53; P(trend continuous) = 0.03]. Current body mass index (BMI) was also positively and significantly associated with risk (multivariate RR comparing >30 kg/m2 with <22.5 kg/m2, 1.35; 95% CI, 1.06-1.70; P(trend) = 0.01). Women with > or = 4 hours/wk of vigorous recreational physical activity had a significantly reduced risk of breast cancer compared with those who reported no recreational physical activity (multivariate RR, 0.78; 95% CI, 0.60-0.99; P(trend) = 0.15). None of these associations with individual energy balance measures was substantially confounded by the other two measures. When we estimated the joint effect of all three variables, women with the most unfavorable energy balance (the highest energy intake, highest BMI, and least physical activity) had twice the risk (RR, 2.10; 95% CI, 1.27-3.45) of women with the most favorable energy balance (the lowest energy intake, lowest BMI, and most physical activity). Although our estimates of absolute energy intake, based on a food frequency questionnaire, are imperfect, these results suggest that energy intake, in addition to BMI and physical activity may be independently associated with breast cancer risk. In addition, these three aspects of energy balance may act jointly in determining breast cancer risk.

Folate intake, alcohol and risk of breast cancer among postmenopausal women in Denmark

OBJECTIVE

There is consistent evidence that alcohol increases the risk of breast cancer. It has been suggested that the increased risk associated with alcohol intake may be reduced by adequate intake of folate. Since many women consume alcohol, detection of a risk-reducing mechanism would have major public health implications.

DESIGN

We therefore evaluated the possible interaction between alcohol and folate in a paired nested case-control study among postmenopausal women.

SETTING

A total of 24 697 postmenopausal women were included in the 'Diet, Cancer and Health' follow-up study between December 1993 and May 1997. The cohort was followed until December 2000. The study included 388 cases of breast cancer and 388 randomly selected controls were used to estimate the breast cancer incidence rate ratio (IRR) in conditional logistic regression analysis.

RESULTS

A previously established association between alcohol intake and risk of breast cancer was present mainly among women with low folate intake. An IRR of 1.19 (95% CI: 0.99-1.42) per 10 g average daily alcohol intake was found for women with a daily folate intake below 300 mug, while among women with a folate intake higher than 350 mug, we could not show an association between the alcohol intake and the breast cancer incidence rate (e.g. folate intake >400 mug; IRR of 1.01 (95% CI: 0.85-1.20)).

CONCLUSION

The findings support the evidence that adequate folate intake may attenuate the risk of breast cancer associated with high alcohol intake.

SPONSORSHIP

The Danish Cancer Society.

p53 Mutation analysis in breast tumors by a DNA microarray method

The p53 gene acts as a regulator of cell growth and DNA repair in normal cells; inactivation of the gene seems to lead to cancer. It is the most commonly mutated gene in human cancers, and a high-throughput sequencing method is needed for cancer etiology studies using large sample sets. In our population-based case-control study of breast cancer, the p53 gene was amplified by PCR for 392 subjects from seven hospitals in Western New York using the Affymetrix GeneChip technology. One hundred thirty-eight (35%) of the breast tumors had p53 mutations, of which 88% were located in exons 5 to 8. New hotspots were identified at codons 179, 195, 196, 213, 217, 249, 254, 278, 281, and 298, and previously reported hotspots were found at codons 175, 248, and 273. Manual sequencing for exons 5 to 9 of the p53 gene was done for 139 tumors to validate the Affymetrix assay. The two methods had 100% concordance for mutations detectable by the Affymetrix assay. We also successfully assayed paraffin-embedded breast and lung tumors from as early as 1958 and employed a nested PCR strategy to improve weak PCR amplification. To have statistical power, the investigation of gene environment interactions and cancer requires a large number of tumor analyses, which are frequently only available from archived tissue from multiple sources. We have shown the utility of the Affymetrix GeneChip method under these challenging conditions and provided new data for the mutational spectra of breast cancer in a population-based study.

Folate intake, alcohol use, and postmenopausal breast cancer risk in the Prostate, Lung, Colorectal, and Ovarian Cancer Screening Trial

BACKGROUND

Several epidemiologic studies suggest that higher folate intakes are associated with lower breast cancer risk, particularly in women with moderate alcohol consumption.

OBJECTIVE

We investigated the association between dietary folate, alcohol consumption, and postmenopausal breast cancer in women from the Prostate, Lung, Colorectal, and Ovarian Cancer Screening Trial cohort.

DESIGN

Dietary data were collected at study enrollment between 1993 and 2001. Folate content was assigned on the basis of prefortification (ie, pre-1998) databases. Of the 25 400 women participants with a baseline age of 55-74 y and with complete dietary and multivitamin information, 691 developed breast cancer between September 1993 and May 2003. We used Cox proportional hazard models with age as the underlying time metric to generate hazard ratios (HRs) and 95% CIs.

RESULTS

The adjusted HRs were 1.19 (95% CI: 1.01, 1.41; P for trend = 0.04) for women reporting supplemental folic acid intake >/=400 mug/d compared with subjects reporting no supplemental intake. Comparison of the highest with the lowest quintile gave adjusted HRs of 1.04 (95% CI: 0.83, 1.31; P for trend = 0.56) and 1.32 (95% CI: 1.04, 1.68; P for trend = 0.03) for food and total folate intake, respectively. Alcohol consumption was positively associated with breast cancer risk (highest compared with lowest quintile: HR = 1.37; 95% CI: 1.08, 1.76; P for trend = 0.02); the risk was greatest in women with lower total folate intake.

CONCLUSIONS

Our results do not support the hypothesis that high folate intake reduces breast cancer risk; instead, they suggest that a high intake, generally attributable to supplemental folic acid, may increase the risk in postmenopausal women. However, our results confirm previous studies showing positive associations between moderate alcohol consumption and breast cancer.

Does dietary folate intake modify effect of alcohol consumption on breast cancer risk? Prospective cohort study

OBJECTIVE

To evaluate the effect of dietary folate intake on the relation between alcohol consumption and breast cancer risk.

DESIGN

Prospective cohort study.

SETTING

Melbourne, Australia.

PARTICIPANTS

17,447 Anglo-Australian women resident in Melbourne, aged 40-69 years at recruitment in 1990-4, and followed up until 31 December 2003.

MAIN OUTCOME MEASURE

Invasive breast cancers diagnosed during follow-up and ascertained through the Victorian cancer registry.

RESULTS

537 invasive breast cancers were diagnosed. Compared with lifetime abstainers, the hazard ratio for breast cancer in women who consumed an average of 40 g or more of alcohol daily at baseline was 1.41 (95% confidence interval 0.90 to 2.23). No direct association was found between dietary folate intake and risk of breast cancer, but a high folate intake mitigated the excess risk associated with alcohol. The estimated hazard ratio of an alcohol consumption of 40 g/day or more was 2.00 (1.14 to 3.49) for women with intakes of 200 mug/day of folate and 0.77 (0.33 to 1.80) for 400 mug/day of folate (P = 0.04 for interaction between alcohol and folate).

CONCLUSIONS

An adequate dietary intake of folate might protect against the increased risk of breast cancer associated with alcohol consumption.

Folate Intake and Risk of Breast Cancer Characterized by Hormone Receptor Status

Folate plays an important role in DNA methylation, and aberrant methylation of the estrogen receptor (ER) gene may be related to the loss of ER gene expression in breast tumors. Thus, deficient folate status has been hypothesized to be associated primarily with ER gene-negative breast tumors, but data relating folate intake to breast cancer risk according to ER status are sparse. We conducted a prospective cohort analysis of folate intake among 88,744 women in the Nurses' Health Study who completed a food frequency questionnaire in 1980 and every 2 to 4 years thereafter. During 20 years of follow-up, 2,812 ER+ and 985 ER- invasive breast cancer cases were documented. Higher total folate intake was significantly associated with lower risk of developing ER- but not ER+ breast cancer; the multivariable relative risks (RR) and 95% confidence intervals (95% CI) comparing the highest to the lowest quintile were 0.81 (0.66-0.99) for ER- tumors and 1.00 (0.89-1.14) for ER+ tumors. The inverse association between total folate intake and ER- breast cancer was mainly present among women consuming at least 15 g/d of alcohol (multivariable RR, 0.46; 95% CI,=0.25-0.86; top versus bottom quintile). These findings support the hypothesis that higher folate intake reduces the risk of developing ER- breast cancer. Ensuring adequate folate intake seems particularly important for women at higher risk of breast cancer because of alcohol consumption.

Dietary fat and risk of breast cancer

BACKGROUND

Breast cancer is one of the major public health problems among women worldwide. A number of epidemiological studies have been carried out to find the role of dietary fat and the risk of breast cancer. The main objective of the present communication is to summarize the evidence from various case-control and cohort studies on the consumption of fat and its subtypes and their effect on the development of breast cancer.

METHODS

A Pubmed search for literature on the consumption of dietary fat and risk of breast cancer published from January 1990 through December 2003 was carried out.

RESULTS

Increased consumption of total fat and saturated fat were found to be positively associated with the development of breast cancer. Even though an equivocal association was observed for the consumption of total monounsaturated fatty acids (MUFA) and the risk of breast cancer, there exists an inverse association in the case of oleic acid, the most abundant MUFA. A moderate inverse association between consumption of n-3 fatty acids and breast cancer risk and a moderate positive association between n-6 fatty acids and breast cancer risk were observed.

CONCLUSION

Even though all epidemiological studies do not provide a strong positive association between the consumption of certain types of dietary fat and breast cancer risk, at least a moderate association does seem to exist and this has a number of implications in view of the fact that breast cancer is an increasing public health concern.

Vitamin D and Calcium Intakes from Food or Supplements and Mammographic Breast Density

BACKGROUND

A better understanding of factors that affect breast density, one of the strongest breast cancer risk indicators, may provide important clues about breast cancer etiology and prevention. This study evaluates the association of vitamin D and calcium, from food and/or supplements, to breast density in premenopausal and postmenopausal women separately.

METHODS

A total of 777 premenopausal and 783 post-menopausal women recruited at two radiology clinics in Quebec City, Canada, in 2001 to 2002, completed a food frequency questionnaire to assess vitamin D and calcium. Breast density from screening mammograms was assessed using a computer-assisted method. Associations between vitamin D or calcium and breast density were evaluated using linear regression models. Adjusted means in breast density were assessed according to the combined daily intakes of the two nutrients using generalized linear models.

RESULTS

In premenopausal women, total intakes of vitamin D and calcium were inversely related to breast density (beta = -1.4; P = 0.004 for vitamin D; beta = -0.8; P = 0.0004 for calcium). In multivariate linear regression, simultaneous increments in daily total intakes of 400 IU vitamin D and 1,000 mg calcium were associated with an 8.5% (95% confidence interval, 1.8-15.1) lower mean breast density. The negative association between dietary vitamin D intake and breast density tended to be stronger at higher levels of calcium intake and vice versa. Among postmenopausal women, intakes of vitamin D and calcium were not associated with breast density.

CONCLUSION

These findings show that higher intakes of vitamin D and calcium from food and supplements are related to lower levels of breast density among premenopausal women. They suggest that increasing intakes of vitamin D and calcium may represent a safe and inexpensive strategy for breast cancer prevention.

Investigation of systemic folate status, impact of alcohol intake and levels of DNA damage in mononuclear cells of breast cancer patients

Folate is required for DNA synthesis, repair and methylation. Low folate status has been implicated in carcinogenesis, possibly as a result of higher rate of genetic damage. The aim of this study is to compare folate status and levels of DNA damage between breast cancer and benign breast disease control patients. Fasting blood samples from 64 histologically confirmed untreated breast cancer patients (mean age 57 years) and 30 benign breast disease control patients (mean age 51 years) were obtained. Red cell folate (RCF) and plasma homocysteine were measured. Mononuclear cells (MNC) were isolated for genetic damage analysis using the basic alkaline comet assay. Results are expressed as tail moment. Data were log transformed as appropriate before analysis for normalisation purposes. The geometric mean (95% confidence interval) of RCF (ng ml⁻¹) in breast cancer patients was 339.07 (333.3–404.6) vs 379.5 (335.8–505.2) in control patients (P=0.24). Corresponding plasma homocysteine concentrations (μmol l⁻¹) were 11.9 (10.6–16.4) vs 10.1 (9.3–11.9) (P=0.073), respectively. The mean tail moment (s.d.) of DNA damage in MNC of breast cancer patients detected by the basic comet assay was 1.4 (0.66) vs –0.17 (0.79) in controls (P<0.0001, t-test), the modified comet assay ‘endonuclease III (Endo III)’ was 1.7 (0.70) vs 0.86 (0.81) (P<0.0001, t-test), and the modified comet assay ‘formamidopyrimidine glycosylase (FPG)’ was 1.6 (0.62) vs 0.99 (0.94) (P<0.0001, t-test). There was a significant negative correlation between RCF levels and DNA damage detected by modified comet assay ‘FPG’ (Pearson Correlation Coefficient r²=−0.26, P=0.02) and DNA damage was found to be significantly higher in MNC of breast cancer patients compared to benign breast disease control patients. Breast cancer patients tended to have lower RCF levels and higher levels of plasma homocysteine, but these differences were not significant. The study provides preliminary evidence that reduced folate status may be implicated in the aetiology of breast cancer perhaps by increasing the in vivo level of genetic instability.

Effects of dietary folate on the development and progression of mammary tumors in rats

Epidemiologic studies have suggested that dietary intake and blood levels of folate may be inversely related to the risk of breast cancer. However, epidemiologic evidence has not been consistent nor has it provided unequivocal support for this purported inverse relationship. Recent evidence has also raised a concern that folate supplementation may promote carcinogenesis if provided after neoplastic foci are established in the target organ. This study investigated the effect of dietary folate deficiency and supplementation on the development and progression of mammary tumors in the N-methyl-N-nitrosourea (MNU) rat model. Weanling, female Sprague-Dawley rats were fed diets containing 0, 2 (control) or 8 mg folic acid/kg diet during the initiation or the promotion phase of MNU-induced mammary tumorigenesis. At necropsy, all macroscopic mammary tumors were identified and histologically confirmed. Dietary folate deficiency and supplementation provided during the initiation phase did not significantly modulate the development of mammary tumors. In contrast, dietary folate deficiency provided during the promotion phase significantly inhibited the rate of appearance, incidence, mean volume and weight of adenocarcinomas compared with the control and supplemental diets. Folate supplementation provided during the promotion phase did not significantly modulate mammary tumorigenesis compared with the control group. These data indicate that moderate folate deficiency inhibits, whereas dietary folate supplementation at four times the basal dietary requirement does not promote, the progression of MNU-induced mammary neoplastic foci in this rat model. However, the limitations associated with the route and dose of MNU administration preclude a definitive conclusion concerning the effect of folate status on the initiation of MNU-induced mammary tumorigenesis.

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.

Effects of moderate alcohol consumption on folate and vitamin B(12) status in postmenopausal women

BACKGROUND

Although alcohol intake has been positively associated with breast cancer risk in epidemiologic studies, a causal relationship has not been established, and the mechanisms mediating this association are speculative. Alcohol may act through altered status of folate and vitamin B(12), two vitamins required for DNA methylation and nucleotide synthesis, and thus cell integrity. Although the effects of heavy alcohol intake on folate and vitamin B(12) status have been well-documented, few studies have addressed the effects of moderate alcohol intake in a controlled setting.

OBJECTIVE

The objective of this study was to determine the effects of moderate alcohol intake on folate and vitamin B(12) status in healthy, well-nourished, postmenopausal women.

DESIGN

The study design was a randomized, diet-controlled crossover intervention. Postmenopausal women (n=53) received three 8-week alcohol treatments in random order: 0, 15, and 30 g/day. Treatment periods were preceded by 2-5-week washout periods. Blood collected at baseline and week 8 of each treatment period was analyzed for serum folate, vitamin B(12), homocysteine (HCY), and methylmalonic acid (MMA) concentrations.

RESULTS

After adjusting for body mass index (BMI), a significant 5% decrease was observed in mean serum vitamin B(12) concentrations from 0 to 30 g of alcohol/day (461.45+/-30.26 vs 440.25+/-30.24 pg/ml; P=0.03). Mean serum HCY concentrations tended to increase by 3% from 0 to 30 g of alcohol/day (9.44+/-0.37 vs 9.73+/-0.37 micromol/l; P=0.05). Alcohol intake had no significant effects on serum folate or MMA concentrations.

CONCLUSIONS

Among healthy, well-nourished, postmenopausal women, moderate alcohol intake may diminish vitamin B(12) status.

Nutritional fats and the risk of type 2 diabetes and cancer

Dietary factors are important predictors for the risk of diabetes type 2. Increased consumption of fibre-rich foods, fruits and vegetables as well as limited amounts of total and saturated fats are essential elements in the prevention of diabetes type 2. The association between these dietary factors and the appearance of diabetes was not only present in cohort studies but were also major elements in the dietary part of the two large diabetes prevention trials (Finnish Diabetes Prevention Study, Diabetes Prevention Program). There is also strong evidence for a relation between obesity and total fat intake and the incidence of certain types of cancers. There is a significant correlation between total fat intake and the risk of cancer; however, it is much weaker than that of the effect of red meat. Recommendations to decrease red meat intake, particularly processed meat, may decrease the risk of colorectal and prostate cancer and may have beneficial effects on breast cancer as well, although this evidence is less compelling. Overall, recommendations focused on controlling or reducing body weight by regular physical activity and avoidance of excessive energy intake from all sources, particularly from fat and saturated fats, by increasing consumption of fibre-rich carbohydrates, vegetables and fruits are effective in decreasing the risk for type 2 diabetes by more than 50% in high-risk individuals. Similar dietary patterns are likely to diminish the manifestation of certain forms of cancers. These conclusions are in agreement with current recommendations for cancer prevention as propagated by the American Cancer Society.

Social marketing as a framework for recruitment: illustrations from the REACH study

OBJECTIVE

Recruitment is often the most challenging aspect of research with older persons. Social marketing--applying marketing techniques to influence the behavior of target audiences to improve their welfare--can help researchers identify factors that influence recruitment.

METHODS

Illustrations of social marketing principles are provided from the Resources for Enhancing Alzheimer's Caregiver Health project, a national Alzheimer's caregivers study that targeted ethnic and racial minorities.

RESULTS

Social marketing principles--the six Ps of participants, product, price, place, promotion, and partners--provide a theoretical framework for organizing and planning recruitment activities, including developing varying strategies to define the target audience (participants), develop the intervention (product), manage time and trouble (price), target the audience, improve accessibility (place), promote the study, and develop and work with partners.

DISCUSSION

Strategies to enhance recruitment are often undertaken without a comprehensive plan. A social marketing plan provides a framework to map out the steps in recruitment that will be needed and to plan for allocations of time, staff, and resources.

Vitamin D, Calcium, and Mammographic Breast Densities

Vitamin D and calcium are being evaluated as potential breast cancer prevention agents. This study reports on the relation of dietary vitamin D and calcium to mammographic breast densities, one of the strongest breast cancer risk factors. Participants were women ages 40 to 60 years who had had a screening mammogram in Rhode Island and eastern Massachusetts (1989–1990). Diet was assessed by semiquantitative food frequency questionnaire, and the percentage of the breast showing densities was estimated visually by a single observer without information on subjects. Multivariate logistic regression was used to compare dietary intakes of vitamin D and calcium between women classified as having few densities (≤30% of the breast with density, n = 287) and extensive densities (≥70% of the breast with density, n = 256). For categories of increasing vitamin D intake (&lt;50, 50–99, 100–199, and ≥200 IU/d), adjusted odds ratios (OR) for extensive densities were 1.00 (reference), 0.51, 0.37, and 0.24, respectively (P for trend = 0.0005). For increasing calcium intake (&lt;500, 500–749, 750–999, and ≥1,000 mg/d), adjusted ORs were 1.00 (reference), 0.63, 0.25, and 0.24, respectively (P for trend = 0.0006). Combination of higher intakes of vitamin D and calcium (≥100 IU/d and ≥750 mg/d, respectively) were associated with a reduction of breast densities (OR, 0.28; 95% confidence interval, 0.15–0.54) compared with those consuming &lt;100 IU/d and &lt;750 mg/d. Increases in vitamin D and calcium intakes were associated with decreases in breast densities, suggesting that dietary vitamin D and calcium could reduce breast cancer risk possibly through influences on breast tissue morphology.