Dietary patterns related to glycemic index and load and risk of premenopausal and postmenopausal breast cancer in the Western New York Exposure and Breast Cancer Study

Dietary Approach of Patients with Hormone-Related Cancer Based on the Glycemic Index and Glycemic Load Estimates

Hormone-related cancers, namely breast, endometrial, cervical, prostate, testicular, and thyroid, constitute a specific group of cancers dependent on hormone levels that play an essential role in cancer growth. In addition to the traditional risk factors, diet seems to be an important environmental factor that partially explains the steadily increased prevalence of this group of cancer. The composition of food, the dietary patterns, the endocrine-disrupting chemicals, and the way of food processing and preparation related to dietary advanced glycation end-product formation are all related to cancer. However, it remains unclear which specific dietary components mediate this relationship. Carbohydrates seem to be a risk factor for cancer in general and hormone-related cancers, in particular, with a difference between simple and complex carbohydrates. Glycemic index and glycemic load estimates reflect the effect of dietary carbohydrates on postprandial glucose concentrations. Several studies have investigated the relationship between the dietary glycemic index and glycemic load estimates with the natural course of cancer and, more specifically, hormone-related cancers. High glycemic index and glycemic load diets are associated with cancer development and worse prognosis, partially explained by the adverse effects on insulin metabolism, causing hyperinsulinemia and insulin resistance, and also by inflammation and oxidative stress induction. Herein, we review the existing data on the effect of diets focusing on the glycemic index and glycemic load estimates on hormone-related cancers.

Association of Inflammatory Diets with Inflammatory Biomarkers in Women at High Genetic Risk for Breast Cancer

Chronically elevated levels of inflammatory biomarkers may contribute to the development of cancer and diet may be an important factor in the interplay between inflammation and cancer. We examined associations between glycemic load (GL), glycemic index (GI), and adapted dietary inflammatory index (ADII) and markers of inflammation and adipokines in 135 premenopausal women at high genetic risk for breast cancer (NCT00892515). We assessed body mass index (BMI), 3-day food records, and blood biomarkers TNF-α, IL-12, CCL2, IL-10, leptin, and adiponectin. Regression models assessed associations between dietary variables and biomarkers, adjusted for caloric intake and BMI. Participants were on average 34.2 years old with mean BMI of 26.8 kg/m². Significantly higher levels of IL-10 and leptin were observed in participants with higher GI. Leptin and adiponectin were significantly associated with ADII. Leptin remained associated with ADII after adjustment for caloric intake and BMI. There were no associations between inflammatory biomarkers of interest and GL, GI, and ADII, after adjusting for caloric intake and BMI. Elevated leptin levels were observed with higher ADII independent of caloric intake and BMI. The relationship between carbohydrate quality and inflammatory potential of the diet and markers of inflammation may be modulated by leptin.

Dietary carbohydrate quality and risk of breast cancer among women

Background

A few studies have examined the relationship between carbohydrate quality index (CQI) and risk of breast cancer (BC) among women in Middle Eastern countries. We studied the associations between carbohydrate quality index and the risk of BC in overall and by menopausal status.

Methods

In this case-control study, dietary intake of 461 women with pathologically confirmed BC within the past year were examined. The same information were collected for 495 apparently healthy controls using a 168-item validated FFQ. Carbohydrate quality was determined by considering four criteria including: ratio of solid carbohydrates to total carbohydrates, dietary fiber intake, GI and the ratio of whole grains to total grains.

Results

Mean GI and GL of participants were totally 57.5 ± 7.2 and 245.7 ± 64.7, respectively. A trend toward significant association was seen between GI and odds of BC in the whole population; such that after stratifying analysis by menopausal status, premenopausal women in the highest quartile of GI were 1.85 times higher likely to have BC than those in the lowest quartile (95% CI: 1.12, 3.07, P = 0.01). We found that women with the greatest CQI had lower odds for BC, compared with those with the lowest CQI (0.63; 95% CI: 0.43–0.94, P = 0.03). This association was remained after stratifying analysis by menopausal status in premenopausal (0.55; 95% CI: 0.34–0.90, P = 0.04).

Conclusion

We found that GI was directly and CQI inversely associated with odds of BC. In order to determine the effects of dietary carbohydrate quality prospective cohort studies are needed.

Sugar-Sweetened Soda Consumption and Total and Breast Cancer Mortality: The Western New York Exposures and Breast Cancer (WEB) Study

BACKGROUND

There is growing evidence of an association between sugar-sweetened beverages (SSB) and increased risk of mortality in various populations. However, SSB influence on mortality among patients with breast cancer is unknown.

METHODS

We assessed the relationship between sugar-sweetened soda and both all-cause and breast cancer mortality among women with incident, invasive breast cancer from the Western New York Exposures and Breast Cancer Study. Breast cancer cases were followed for a median of 18.7 years, with ascertainment of vital status via the National Death Index. Frequency of sugar-sweetened soda consumption was determined via dietary recall using a food frequency questionnaire. Cox proportional hazards, adjusting for relevant variables, were used to estimate HRs and 95% confidence intervals (CI).

RESULTS

Of the 927 breast cancer cases, 386 (54.7%) had died by the end of follow-up. Compared with never/rarely sugar-sweetened soda drinkers, consumption at ≥5 times per week was associated with increased risk of both total (HR = 1.62; 95% CI, 1.16-2.26; P _trend < 0.01) and breast cancer mortality (HR = 1.85; 95% CI, 1.16-2.94; P _trend < 0.01). Risk of mortality was similarly increased among ER-positive, but not ER-negative patients; among women with body mass index above the median, but not below the median; and among premenopausal, but not postmenopausal women for total mortality only.

CONCLUSIONS

Reported higher frequency of sugar-sweetened soda intake was associated with increased risks of both total and breast cancer mortality among patients with breast cancer.

IMPACT

These results support existing guidelines on reducing consumption of SSB, including for women with a diagnosis of breast cancer.

Associations between dietary patterns and the risk of breast cancer: a systematic review and meta-analysis of observational studies

BACKGROUND

Epidemiologic evidence suggests that certain dietary patterns were associated with breast cancer risk, but the results have been inconclusive. We assessed the associations between different dietary patterns and the risk of breast cancer by conducting a meta-analysis of observational studies.

METHODS

Relevant articles were searched in PubMed, Embase, and Cochrane library databases through September 2017. Multivariable-adjusted relative risks (RRs) and 95% confidence intervals (CIs) comparing the highest and lowest categories of Western and prudent dietary patterns were combined by using the random-effects meta-analyses.

RESULTS

We identified 32 eligible articles including 14 cohort and 18 case-control studies (34 Western and 35 prudent studies). The pooled analyses found that a Western dietary pattern was associated with a 14% increased risk (RR 1.14, 95% CI 1.02, 1.28), whereas a prudent dietary pattern was associated with an 18% reduced risk of breast cancer (RR 0.82, 95% CI 0.75, 0.89). In addition, sub-group analyses showed that the positive association between a Western dietary pattern and breast cancer risk was significant among postmenopausal (RR 1.20, 95% CI 1.06, 1.35), but not premenopausal women (RR 1.18, 95% CI 0.99, 1.40), and significant for hormone receptor-positive tumors (RR 1.18, 95% CI 1.04, 1.33), but not receptor-negative tumors (RR 0.97, 95% CI 0.83, 1.12). In contrast, the inverse association between a prudent dietary pattern and breast cancer was significant in premenopausal (RR 0.77, 95% CI 0.61, 0.98), but not postmenopausal women (RR 0.88, 95% CI 0.74, 1.03), and significant for both hormone receptor-positive and receptor-negative tumors.

CONCLUSIONS

The results of the current meta-analysis suggest a possible increased risk of breast cancer associated with a Western dietary pattern and a reduced risk with a prudent dietary pattern. Large-scale cohort studies with a high quality need to be conducted to further confirm the findings of the current meta-analysis. As dietary patterns are modifiable, these findings may provide viable strategies for breast cancer prevention through changes in dietary intake.

Dietary patterns: a literature review of the methodological characteristics of the main step of the multivariate analyzes

OBJECTIVE

To describe the solutions adopted in the multiple steps of the use of multivariate techniques to obtain a dietary pattern (DP) concerning: the objective of the studies, the selection of the method for measuring food intake, the criteria for grouping the foods, the number of food groups used, the number of DP obtained, and the nomenclature criteria.

METHODS

The articles were selected from MEDLINE and Lilacs scientific databases using the following keywords: "dietary patterns" versus "factor analysis"; "principal components analysis"; "cluster analysis" and "reduced regression rank." The initial search resulted in 1,752 articles. After inclusion and exclusion criteria, 189 publications were selected.

RESULTS

The following aspects were relevant among the studies: the prevalence of the principal component analysis (PCA); the prevalence of the use of 4 to 5 DPs in the studies of association with health outcomes; the use of 30 or more food groups from the food frequency questionnaire (FFQ); the prevalence of studies that associated DPs with health outcomes and socioeconomic factors; and the heterogeneity of criteria used throughout the analytical stages of the multivariate techniques.

CONCLUSION

The heterogeneity between the publications concentrates on the criteria for food grouping, the nomenclature, and the number of dietary patterns calculated, which varied depending on the number of food groups present in these analyses. To understand, apply, and explore in full, the multivariate techniques has become necessary in order to improve the reliability of the results and, consequently, to improve the relationships with health outcomes and socioeconomic factors.

Using reduced rank regression methods to identify dietary patterns associated with obesity: a cross-country study among European and Australian adolescents

This study aims to examine repeatability of reduced rank regression (RRR) methods in calculating dietary patterns (DP) and cross-sectional associations with overweight (OW)/obesity across European and Australian samples of adolescents. Data from two cross-sectional surveys in Europe (2006/2007 Healthy Lifestyle in Europe by Nutrition in Adolescence study, including 1954 adolescents, 12-17 years) and Australia (2007 National Children's Nutrition and Physical Activity Survey, including 1498 adolescents, 12-16 years) were used. Dietary intake was measured using two non-consecutive, 24-h recalls. RRR was used to identify DP using dietary energy density, fibre density and percentage of energy intake from fat as the intermediate variables. Associations between DP scores and body mass/fat were examined using multivariable linear and logistic regression as appropriate, stratified by sex. The first DP extracted (labelled 'energy dense, high fat, low fibre') explained 47 and 31 % of the response variation in Australian and European adolescents, respectively. It was similar for European and Australian adolescents and characterised by higher consumption of biscuits/cakes, chocolate/confectionery, crisps/savoury snacks, sugar-sweetened beverages, and lower consumption of yogurt, high-fibre bread, vegetables and fresh fruit. DP scores were inversely associated with BMI z-scores in Australian adolescent boys and borderline inverse in European adolescent boys (so as with %BF). Similarly, a lower likelihood for OW in boys was observed with higher DP scores in both surveys. No such relationships were observed in adolescent girls. In conclusion, the DP identified in this cross-country study was comparable for European and Australian adolescents, demonstrating robustness of the RRR method in calculating DP among populations. However, longitudinal designs are more relevant when studying diet-obesity associations, to prevent reverse causality.

Healthy dietary patterns and risk of breast cancer by molecular subtype

We examined associations between dietary quality indices and breast cancer risk by molecular subtype among 100,643 women in the prospective Nurses' Health Study (NHS) cohort, followed from 1984 to 2006. Dietary quality scores for the Alternative Healthy Eating Index (AHEI), alternate Mediterranean diet (aMED), and Dietary Approaches to Stop Hypertension (DASH) dietary patterns were calculated from semi-quantitative food frequency questionnaires collected every 2-4 years. Breast cancer molecular subtypes were defined according to estrogen receptor (ER), progesterone receptor, human epidermal growth factor 2 (HER2), cytokeratin 5/6 (CK5/6), and epidermal growth factor receptor status from immunostained tumor microarrays in combination with histologic grade. Cox proportional hazards models, adjusted for age and breast cancer risk factors, were used to estimate hazard ratios (HRs) and 95 % confidence intervals (CIs). Competing risk analyses were used to assess heterogeneity by subtype. We did not observe any significant associations between the AHEI or aMED dietary patterns and risk of breast cancer by molecular subtype. However, a significantly reduced risk of HER2-type breast cancer was observed among women in 5th versus 1st quintile of the DASH dietary pattern [n = 134 cases, Q5 vs. Q1 HR (95 % CI) = 0.44 (0.25-0.77)], and the inverse trend across quintiles was significant (p trend = 0.02). We did not observe any heterogeneity in associations between AHEI (p het = 0.25), aMED (p het = 0.71), and DASH (p het = 0.12) dietary patterns and breast cancer by subtype. Adherence to the AHEI, aMED, and DASH dietary patterns was not strongly associated with breast cancer molecular subtypes.

Lifestyle in Iranian Patients with Breast Cancer

BACKGROUND

One of the most commonly diagnosed cancers is breast cancer that leads to mortality and morbidity among Iranian women. Behavioural risk factors, such as common lifestyle patterns are often associated with risk of breast cancer incidence.

AIM

This study aimed to investigate lifestyle of breast cancer patients admitted to Cancer Research Center of Mazandaran University of Medical Sciences.

MATERIALS AND METHODS

This descriptive cross-sectional study was conducted using convenient sampling method. Sample size consisted of 150 cancer patients, and data collection tool included a researcher-made questionnaire on dimensions of lifestyle containing four dimensions of self-care, exercise and physical activity, diet and coping with stress. Maximum score in different dimensions, based on 100% of marks earned, was evaluated in three categories of undesirable, relatively desirable and desirable. Data were analysed with SPSS-19 software using descriptive statistics (relative and absolute frequencies, mean and standard deviation).

RESULTS

In total of 150 women, the mean age of patients was 51.9 ± 1.04 (27-78). The majority of participants were married, housewives, with high school education. Among the four parts of healthy lifestyle, desirable level of physical activity and exercise had the least participants, and in the dimensions of physical activity and exercise, the lowest level related to walking, followed by daily exercise. Most of the participants had undesirable level of self-care and lowest frequency related to mammography after 40-year-old, followed by annual check-up and Pap-smear. With regard to nutrition, most of them were at desirable level.

CONCLUSION

The results indicated undesirable levels in two lifestyle dimensions (self-care and physical activity and exercise) in the majority of participants for a year before contracting breast cancer. Primary prevention programs should be implemented with a comprehensive approach, thus, effective strategies are required to modify lifestyle.

Dietary patterns derived with multiple methods from food diaries and breast cancer risk in the UK Dietary Cohort Consortium

BACKGROUND/OBJECTIVES

In spite of several studies relating dietary patterns to breast cancer risk, evidence so far remains inconsistent. This study aimed to investigate associations of dietary patterns derived with three different methods with breast cancer risk.

SUBJECTS/METHODS

The Mediterranean Diet Score (MDS), principal components analyses (PCA) and reduced rank regression (RRR) were used to derive dietary patterns in a case-control study of 610 breast cancer cases and 1891 matched controls within four UK cohort studies. Dietary intakes were collected prospectively using 4- to 7-day food diaries and resulting food consumption data were grouped into 42 food groups. Conditional logistic regression models were used to estimate odds ratios (ORs) for associations between pattern scores and breast cancer risk adjusting for relevant covariates. A separate model was fitted for post-menopausal women only.

RESULTS

The MDS was not associated with breast cancer risk (OR comparing first tertile with third 1.20 (95% CI 0.92; 1.56)), nor the first PCA-derived dietary pattern, explaining 2.7% of variation of diet and characterized by cheese, crisps and savoury snacks, legumes, nuts and seeds (OR 1.18 (95% CI 0.91; 1.53)). The first RRR-derived pattern, a 'high-alcohol' pattern, was associated with a higher risk of breast cancer (OR 1.27; 95% CI 1.00; 1.62), which was most pronounced in post-menopausal women (OR 1.46 (95% CI 1.08; 1.98)).

CONCLUSIONS

A 'high-alcohol' dietary pattern derived with RRR was associated with an increased breast cancer risk; no evidence of associations of other dietary patterns with breast cancer risk was observed in this study.

Consumption of a high glycemic load but not a high glycemic index diet is marginally associated with oxidative stress in young women

Research studies have suggested that chronic consumption of high glycemic index foods may lead to chronically high oxidative stress. This is important because oxidative stress is suspected to be an early event in the etiology of many disease processes. We hypothesized that dietary glycemic index and glycemic load were positively associated with oxidative stress assessed by plasma F2-isoprostanes in healthy, premenopausal women (body mass index [BMI] = 24.7 ± 4.8 kg/m(2) and age 25.3 ± 3.5 years, mean ± SD). We measured plasma F2-isoprostanes in 306 healthy premenopausal women at the baseline visit for the Women In Steady Exercise Research study, using gas chromatography-mass spectrometry. Dietary glycemic index and load were calculated from the National Cancer Institute Diet History Questionnaire, and participants were divided into quartiles of dietary glycemic index and of glycemic load. Plasma F2-isoprostanes were compared across quartile groups of dietary glycemic index and glycemic load using linear regression models. Plasma F2-isoprostanes (pg/mL) increased with quartile of glycemic load (test for linear trend, P = .033), and also increased with quartile of glycemic index in participants with BMI ≥ 25 (P = .035) but not in those with BMI <25 (P = .924). After adjustment for BMI, alcohol consumption and total energy intake, both these positive trends remained marginally significant (P = .123 for quartiles of glycemic index and P = .065 for quartiles of glycemic load).

The influence of fasting insulin level in post-gestational diabetes mellitus women receiving low-glycaemic-index diets

Post-gestational diabetes mellitus (GDM) women are recommended weight loss to manage increased cardio-metabolic risks. We investigated the effects of lowering diet glycaemic index (GI) on fasting blood glucose (FBG), serum lipids, body weight and composition of post-GDM women with varying fasting insulin levels (INS). Seventy-seven Asian, non-diabetic women with previous GDM (aged 20–40 years, mean BMI: 26.4±4.6 kg m⁻²) were recruited. At baseline, 20 subjects with INS <2 μIU ml⁻¹ and 18 with INS ⩾2 μIU ml⁻¹ received conventional dietary recommendations (CHDR) only. CHDR emphasised energy and fat intake restriction and encouraged increase in dietary fibre intakes. Twenty-four subjects with INS <2 μIU ml⁻¹ and 15 with INS ⩾2 μIU ml⁻¹, in addition to CHDR, received low-GI education (LGI). Changes in FBG, serum lipids, body weight and body composition were evaluated. Subjects with INS <2 μIU ml⁻¹ had similar outcomes with both diets. After 1 year, subjects with INS ⩾2 μIU ml⁻¹ who received LGI education had reductions in FBG and triglycerides. Subjects who received CHDR observed increase in both FBG and triglycerides (P<0.05). Among all subjects, diet GI was lower and dietary fibre intakes were higher in LGI compared with CHDR subjects (all P<0.05). Thus, in Asian post-GDM women with normal/higher INS, adding low-GI education to CHDR improved management of FBG and triglycerides.

Dietary patterns: a novel approach to examine the link between nutrition and cognitive function in older individuals

Cognitive decline may lead to dementia whose most frequent cause is Alzheimer's disease (AD). Among the many potential risk factors of cognitive decline and AD, diet raises increasing interest. Most studies considered diet in the frame of a single nutrient approach with inconsistent results. A novel approach to examine the link between nutrition and cognitive function is the use of dietary patterns. The aim of the present review was to update and complete the body of knowledge about dietary patterns in relationship with various cognitive outcomes in the elderly. Two approaches can be used: a priori and a posteriori patterns. A priori patterns are defined by the adhesion to a pre-defined healthy diet using a score such as the Mediterranean diet (MeDi) score, the Healthy Eating Index, the Canadian Healthy Eating Index, the French National Nutrition and Health Programme (Programme National Nutrition Santé) Guideline Score (PNNS-GS), the Recommended Food Score (RFS) and Dietary Approaches to Stop Hypertension (DASH). MeDi score, RFS, PNNS-GS and DASH have been associated with lower risks of cognitive impairment, cognitive decline, and dementia or AD. Principal components analysis, reduced rank regression and clustering methods allow the identification of 'healthy' patterns associated with lower risk of cognitive decline. However, some studies did not report any associations with cognitive outcomes and results are discordant especially regarding MeDi and the risk of dementia. Several methodological challenges should be overcome to provide a higher level of evidence supporting the development of nutritional policies to prevent cognitive decline and AD.

A dietary pattern derived to correlate with estrogens and risk of postmenopausal breast cancer

Circulating estrogens are an established risk factor for breast cancer and some data suggest that diet may influence estrogen levels. Therefore, using a subsample (n = 550) of women from a large cohort, we applied reduced rank regression to identify a dietary pattern that was correlated with estradiol and estrone sulfate. We then adapted the pattern to be used with the full cohort (n = 67,802) and prospectively assessed its association with postmenopausal breast cancer. The estrogen food pattern, characterized by higher intakes of red meat, legumes, and pizza, but lower intakes of coffee and whole grains, was modestly but significantly correlated with estradiol (r = 0.14) and estrone sulfate (r = 0.20). During 22 years of follow-up, we ascertained 4,596 incident breast cancer, with 2,938 estrogen receptor-positive tumors and 689 estrogen receptor-negative tumors. However, after adjusting for potential confounders, we did not observe any association with overall estrogen receptor-positive or estrogen receptor-negative breast cancer. In conclusion, diet pattern appeared to only have modest association with estrogens, and was not associated with postmenopausal breast cancer risk. Although these results were null, it should be repeated in other populations as differences in food intake may yield a dietary pattern with stronger association with estrogens.

Promoter methylation of E-cadherin, p16, and RAR-β(2) genes in breast tumors and dietary intake of nutrients important in one-carbon metabolism

Aberrant DNA methylation plays a critical role in carcinogenesis, and the availability of dietary factors involved in 1-carbon metabolism may contribute to aberrant DNA methylation. We investigated the association of intake of folate, vitamins B(2), B(6), B(12), and methionine with promoter methylation of E-cadherin, p16, and RAR-β(2) genes in archived tumor tissues from incident, primary breast cancer cases in a population-based case-control study. Real-time methylation-specific PCR was performed on 803 paraffin-embedded samples; usual dietary intake was queried from a food frequency questionnaire. Unconditional logistic regression was used to derive adjusted odds ratios and 95% confidence intervals for likelihood of promoter methylation for high compared to low intake of those 1-carbon nutrients. Overall, in case-case comparisons, dietary intakes of folate, vitamins B(2), B(6), B(12), and methionine were not associated with likelihood of promoter methylation of E- cadherin, p16, and RAR-β(2) for all cases combined or within strata defined by menopausal status and estrogen receptor status in this study. This finding, however, does not exclude the possibility that intake of such nutrients might have the ability to modulate promoter methylation in normal or premalignant (dysplastic) breast tissue.

Dietary glycemic load, glycemic index, and carbohydrate and risk of breast cancer in the Women's Health Initiative

Dietary glycemic load (GL), glycemic index (GI), and carbohydrate could be associated with breast cancer risk by influencing long-term blood glucose and insulin concentrations. We examined associations between GL, GI, and carbohydrate and incident breast cancer in 148,767 Women's Heath Initiative (WHI) participants. Dietary variables were estimated from food frequency questionnaires administered at baseline. Self-reported breast cancers during follow-up were confirmed by medical records review. Cox proportional hazards regression modeled time to breast cancer within quintiles of GL, GI, and carbohydrate. There were 6,115 total breast cancers after a median follow-up of 8.0 yr. We observed no associations between GL, GI, or carbohydrate and total incident breast cancer, with hazard ratios and 95% confidence intervals for the highest vs. lowest quintiles of 1.08, 0.92-1.29 (P for trend = 0.27); 1.01, 0.91-1.12 (P = 0.74); and 0.95, 0.80-1.14 (P = 0.98), respectively. There was a trend toward significance for the positive association between GL and in situ cancers (1.40, 0.94-2.13; P = 0.07). Although there was no evidence of associations between GL, GI, or carbohydrate and total breast cancer risk in WHI participants, the suggestion of an association between GL and risk of in situ cancers requires further investigation.

Dietary fiber, carbohydrates, glycemic index, and glycemic load in relation to breast cancer prognosis in the HEAL cohort

BACKGROUND

Dietary intake of fiber, carbohydrate, glycemic index (GI), and glycemic load (GL) may influence breast cancer survival, but consistent and convincing evidence is lacking.

METHODS

We investigated associations of dietary fiber, carbohydrates, GI, and GL with breast cancer prognosis among n = 688 stage 0 to IIIA breast cancer survivors in the Health, Eating, Activity, and Lifestyle (HEAL) study. Premenopausal and postmenopausal women from Western Washington State, Los Angeles County, and New Mexico participated. Usual diet was assessed with a food frequency questionnaire. Total mortality, breast cancer mortality, nonfatal recurrence, and second occurrence data were obtained from SEER (Surveillance, Epidemiology, and End Results) registries and medical records. Cox proportional hazards regression estimated multivariate-adjusted hazard ratios and 95% confidence intervals (CI).

RESULTS

During a median of 6.7 years follow-up after diagnosis, n = 106 total deaths, n = 83 breast cancer-specific deaths, and n = 82 nonfatal recurrences were confirmed. We observed an inverse association between fiber intake and mortality. Multivariate-adjusted hazard rate ratios (HRR) comparing high to low intake were 0.53 (95% CI 0.23-1.23) and 0.75 (95% CI 0.43-1.31). A threshold effect was observed whereby no additional benefit was observed for intakes of 9 g/d or more. Fiber intake was suggestively inversely associated with breast cancer-specific mortality (HRR = 0.68, 95% CI 0.27-1.70) and risk of nonfatal recurrence or second occurrence (HRR = 0.68, 95% CI 0.27-1.70), but results were not statistically significant.

CONCLUSION

Dietary fiber was associated with a nonsignificant inverse association with breast cancer events and total mortality. Further studies to assess and confirm this relationship are needed in order to offer effective dietary strategies for breast cancer patients.

IMPACT

Increasing dietary fiber may an effective lifestyle modification strategy for breast cancer survivors.

Healthy lifestyle on the risk of breast cancer

BACKGROUND

Many studies have analyzed the effect of behavioral risk factors such as common lifestyle patterns on the risk of disease. The aim of this study was to assess the effect of a healthy lifestyle index on the risk of breast cancer.

METHODS

A population-based case-control study was conducted in Mexico from 2004 to 2007. One thousand incident cases and 1,074 controls, matched to cases by 5-year age category, region, and health institution, participated in the study. A healthy lifestyle index was developed by means of principal components by using dietary pattern, physical activity, alcohol consumption, and tobacco smoking. A conditional logistic regression model was used to assess this association.

RESULTS

The healthy lifestyle index was defined as the combined effect of moderate and/or vigorous-intensity physical activity, low consumption of fat, processed foods, refined cereals, complex sugars, and the avoidance of tobacco smoking and alcohol consumption. Results showed a protective effect on both pre- (OR = 0.50, 95% CI: 0.29-0.84) and postmenopausal women (OR = O.20, 95% CI: 0.11-0.37) when highest versus lowest index quintiles were compared.

CONCLUSIONS

Healthy lifestyle was associated with a reduction in the odds of having breast cancer. Primary prevention of this disease should be promoted in an integrated manner. Effective strategies need to be identified to engage women in healthy lifestyles.

IMPACT

This study is the first to assess a healthy lifestyle index in relation to the risk of breast cancer.

A comparison of three statistical methods applied in the identification of eating patterns

This work aimed to compare the results of three statistical methods applied in the identification of dietary patterns. Data from 1,009 adults between the ages of 20 and 65 (339 males and 670 females) were collected in a population-based cross-sectional survey in the Metropolitan Region of Rio de Janeiro, Brazil. Information on food consumption was obtained using a semi-quantitative food frequency questionnaire. A factor analysis, cluster analysis, and reduced rank regression (RRR) analysis were applied to identify dietary patterns. The patterns identified by the three methods were similar. The factor analysis identified "mixed", "Western", and "traditional" eating patterns and explained 35% of the data variance. The cluster analysis identified "mixed" and "traditional" patterns. In the RRR, the consumption of carbohydrates and lipids were included as response variables and again "mixed" and "traditional" patterns were identified. Studies comparing these methods can help to inform decisions as to which procedures best suit a specific research scenario.

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

BACKGROUND

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

OBJECTIVE

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

DESIGN

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

RESULTS

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

CONCLUSION

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

Food combination and Alzheimer disease risk: a protective diet

OBJECTIVE

To assess the association between food combination and Alzheimer disease (AD) risk. Because foods are not consumed in isolation, dietary pattern (DP) analysis of food combination, taking into account the interactions among food components, may offer methodological advantages.

DESIGN

Prospective cohort study.

SETTING

Northern Manhattan, New York, New York.

PATIENTS OR OTHER PARTICIPANTS

Two thousand one hundred forty-eight community-based elderly subjects (aged > or = 65 years) without dementia in New York provided dietary information and were prospectively evaluated with the same standardized neurological and neuropsychological measures approximately every 1.5 years. Using reduced rank regression, we calculated DPs based on their ability to explain variation in 7 potentially AD-related nutrients: saturated fatty acids, monounsaturated fatty acids, omega-3 polyunsaturated fatty acids, omega-6 polyunsaturated fatty acids, vitamin E, vitamin B(12), and folate. The associations of reduced rank regression-derived DPs with AD risk were then examined using a Cox proportional hazards model. Main Outcome Measure Incident AD risk.

RESULTS

Two hundred fifty-three subjects developed AD during a follow-up of 3.9 years. We identified a DP strongly associated with lower AD risk: compared with subjects in the lowest tertile of adherence to this pattern, the AD hazard ratio (95% confidence interval) for subjects in the highest DP tertile was 0.62 (0.43-0.89) after multivariable adjustment (P for trend = .01). This DP was characterized by higher intakes of salad dressing, nuts, fish, tomatoes, poultry, cruciferous vegetables, fruits, and dark and green leafy vegetables and a lower intake of high-fat dairy products, red meat, organ meat, and butter.

CONCLUSION

Simultaneous consideration of previous knowledge regarding potentially AD-related nutrients and multiple food groups can aid in identifying food combinations that are associated with AD risk.

Dietary lignan intakes in relation to survival among women with breast cancer: the Western New York Exposures and Breast Cancer (WEB) Study

Dietary lignan intakes have been associated with reduced breast cancer risks; however, no previous studies have investigated whether lignan intake might be associated with breast cancer survival. We examined the association of dietary lignan intakes with survival in 1122 women with primary, incident, histologically confirmed breast cancer identified between 1996 and 2001, and with vital status determined through December 31, 2006. Diet in the 12-24 months before diagnosis was assessed with an extensive food frequency questionnaire, and potential confounders assessed from an extensive epidemiologic interview and abstracted clinical data. Lignan intake was calculated using published food composition data. Hazard ratios (HR), and 95% confidence intervals (CIs) for dietary lignan intakes with all cause, and breast cancer mortality were estimated using Cox proportional hazards adjusting for age, education, race, total energy intake, tumor stage, and body mass index. Of the 1122 women with complete dietary data, 160 had died by the end of follow-up. Among postmenopausal women only, those in the highest versus lowest quartile of lignan intakes had a statistically significant reduction in the risk of all cause mortality (HR 0.49, 95% CI 0.26-0.91) and a significantly reduced risk of breast cancer mortality (HR 0.29, 95% CI 0.11-0.76). Higher intakes of dried beans (HR 0.61, 95% CI 0.36-1.03), but not fruits, vegetables, or grains, were also weakly associated with overall mortality. In summary, our results suggest that higher lignan intakes may be associated with improved survival among postmenopausal women with breast cancer.

Dietary patterns, risk and prognosis of breast cancer

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

Dietary patterns and breast cancer risk in women participating in the Black Women's Health Study

BACKGROUND

No studies have examined dietary patterns and breast cancer risk in a large cohort of African American women.

OBJECTIVE

We investigated the association between dietary patterns and breast cancer risk in the Black Women's Health Study.

DESIGN

This is a prospective cohort study of 50,778 participants followed biennially from 1995 through 2007. During 443,742 person-years of follow-up, 1094 incident cases of breast cancer were identified. Factor analysis was used to derive food patterns based on 69 food variables. We used Cox regression models to obtain incident rate ratios (IRRs) for breast cancer in relation to quintiles of each of the 2 dietary patterns, with adjustment for other breast cancer risk factors.

RESULTS

Through factor analysis, we identified 2 dietary patterns: Western (refined grains, processed meat, and sweets) and prudent (whole grains, vegetables, fruit, and fish). The prudent diet was weakly associated with lower breast cancer risk overall; P for trend = 0.06. In analyses stratified by body mass index (BMI; in kg/m(2)), the prudent dietary pattern was associated with a significantly lower risk of breast cancer in women with a BMI <25 (IRR: 0.64; 95% CI: 0.43, 0.93; P for trend = 0.01). The prudent dietary pattern was also associated with a significantly lower risk of breast cancer in premenopausal women (IRR: 0.70; 95% CI: 0.52, 0.96; P for trend = 0.01), and we found a significant inverse association for the prudent dietary pattern and estrogen receptor-negative breast cancer (IRR: 0.52; 95% CI: 0.28, 0.94; P for trend <0.01).

CONCLUSION

Our findings suggest that the prudent dietary pattern may protect against breast cancer in some black women.

Dietary patterns associated with glycemic index and glycemic load among Alberta adolescents

The purpose of this study was to assess the dietary glycemic index (GI) and glycemic load (GL) of adolescents, based on a Web-based 24-h recall, and to investigate dietary predictors of GI and GL. In addition, the relationship between GI and GL and weight status was examined. A Web-based 24-h recall was completed by 4936 adolescents, aged 9–17 years; macronutrient and food group intakes were assessed using the ESHA Food Processor, the Canadian Nutrient File, and Canada’s Food Guide. Dietary GI and GL were calculated based on published GI values for foods. Students provided self-reported height and mass. Multiple regression models assessed the ability of food group choices and food behaviours to predict GI and GL. Mean GI was 55 for girls and 56 for boys. Mean GL was 128 for girls and 168 for boys. Food group choices explained 26% of the variation in GI (p < 0.01) and 84% of the variation in GL (p < 0.01). The number of meals per day explained 10% (p < 0.01), and eating meals outside of the home accounted for 2.5% (p < 0.01) of the variation in GL; however, these results disappeared when adjusted for total energy intake. The GI was positively correlated with body mass index in girls (r = 0.05, p = 0.02), and GL was significantly higher among nonoverweight boys than overweight boys. This study identified eating patterns related to daily GI and GL, and suggests certain dietary patterns that could have beneficial effects on health. It also showed that GI and GL were weakly related to weight status.

Impact of diet on breast cancer risk

PURPOSE OF REVIEW

Breast cancer is the most common female cancer in Western Europe and North America, and becoming an increasing problem in developing countries such as India and China. We review recent studies (published 1 January 2007-31 August 2008) on the impact of diet on breast cancer risk.

RECENT FINDINGS

Recent studies have focused on the controversial association for dietary fat and breast cancer as well as the role of newer aspects such as glycemic index, dietary patterns and diet-gene interactions. Evidence that some of the associations may be modified by oestrogen and progesterone receptor status has been presented. Still, only alcohol intake, being overweight and weight gain have shown consistent and strong positive associations with breast cancer risk. The reasons for the null or weak associations often observed regarding diet and breast cancer might be several. For example, there may be no causal association, or existing associations may be masked by measurement error, timing of dietary exposure and differences according to tumour characteristics or diet-gene interactions.

SUMMARY

Numerous epidemiological studies on diet and breast cancer have been published during our review period. Still, only alcohol intake, being overweight and weight gain have shown consistent and strong positive associations with breast cancer risk.

Consumption of sweet foods and breast cancer risk: a case-control study of women on Long Island, New York

Several epidemiologic studies have reported a positive association between breast cancer risk and high intake of sweets, which may be due to an insulin-related mechanism. We investigated this association in a population-based case-control study of 1,434 cases and 1,440 controls from Long Island, NY. Shortly after diagnosis, subjects were interviewed in-person to assess potential breast cancer risk factors, and self-completed a modified Block food frequency questionnaire, which included 11 items pertaining to consumption of sweets (sweet beverages, added sugars, and various desserts) in the previous year. Using unconditional logistic regression models, we estimated the association between consumption of sweets and breast cancer. Consumption of a food grouping that included dessert foods, sweet beverages, and added sugars was positively associated with breast cancer risk [adjusted odds ratio (OR) comparing the highest to the lowest quartile: 1.27, 95% confidence interval (CI): 1.00-1.61]. The OR was slightly higher when only dessert foods were considered (OR: 1.55, 95% CI: 1.23-1.96). The association with desserts was stronger among pre-menopausal women (OR: 2.00, 95% CI: 1.32-3.04) than post-menopausal women (OR: 1.40, 95% CI: 1.07-1.83), although the interaction with menopause was not statistically significant. Our study indicates that frequent consumption of sweets, particularly desserts, may be associated with an increased risk of breast cancer. These results are consistent with other studies that implicate insulin-related factors in breast carcinogenesis.

Glycemic load, glycemic index, and body mass index in Spanish adults

BACKGROUND

Studies on obesity and glycemic index (GI) or glycemic load (GL) have had inconsistent results, perhaps in part because of underreporting or to heterogeneous dietary patterns across food cultures.

OBJECTIVES

We examined associations between body mass index (BMI) and GI or GL in a Mediterranean population, accounting for underreporting. We also constructed dietary factors related to GI and GL to better understand food patterns related to these measures.

DESIGN

Cross-sectional data on 8195 Spanish adults aged 35-74 y were analyzed. A validated food-frequency questionnaire was used to estimate GI and GL, with glucose as the reference value. Reduced-rank regression was used to construct dietary patterns that explained variation in GI and GL. Multivariate linear regression was used to estimate associations between BMI and GI, GL, and their respective diet factors with and without adjusting for energy, which may lie on the causal pathway between glycemic quality and obesity. Effects of excluding underreporters (ratio of energy intake:basal metabolic rate < 1.20) were examined.

RESULTS

Food patterns underlying high GI differed substantially from those of high GL, with fruits, vegetables, and legumes related positively to GL but negatively to GI. After excluding underreporters, GL was negatively associated with BMI, adjusting for energy. GI was not associated with BMI in any model.

CONCLUSIONS

After adjusting for energy, GL was associated with reduced BMI in this Mediterranean population. Underreporting did not explain this inverse relation, which was observed among subjects with plausible intakes.

Dietary patterns and breast cancer recurrence and survival among women with early-stage breast cancer

PURPOSE

To determine the association of dietary patterns with cancer recurrence and mortality of early-stage breast cancer survivors.

PATIENTS AND METHODS

Patients included 1,901 Life After Cancer Epidemiology Study participants diagnosed with early-stage breast cancer between 1997 and 2000 and recruited primarily from the Kaiser Permanente Northern California Cancer Registry. Diet was assessed at cohort entry using a food frequency questionnaire. Two dietary patterns were identified: prudent (high intakes of fruits, vegetables, whole grains, and poultry) and Western (high intakes of red and processed meats and refined grains). Two hundred sixty-eight breast cancer recurrences and 226 all-cause deaths (128 attributable to breast cancer) were ascertained. Cox proportional hazards models were used to estimate hazard ratios (HRs) and 95% CIs.

RESULTS

Increasing adherence to a prudent dietary pattern was associated with a statistically significant decreasing risk of overall death (P trend = .02; HR for highest quartile = 0.57; 95% CI, 0.36 to 0.90) and death from non-breast cancer causes (P trend = .003; HR for highest quartile = 0.35; 95% CI, 0.17 to 0.73). In contrast, increasing consumption of a Western dietary pattern was related to an increasing risk of overall death (P trend = .05) and death from non-breast cancer causes (P = .02). Neither dietary pattern was associated with risk of breast cancer recurrence or death from breast cancer. These observations were generally not modified by physical activity, being overweight, or smoking.

CONCLUSION

Women diagnosed with early-stage breast cancer might improve overall prognosis and survival by adopting more healthful dietary patterns.

A food pattern that is predictive of flavonol intake and risk of pancreatic cancer

BACKGROUND

In the Multiethnic Cohort (MEC) study, we showed inverse associations between flavonols and pancreatic cancer risk.

OBJECTIVE

We aimed to define a food pattern associated with intakes of quercetin, kaempferol, and myricetin; to examine the association of that pattern with pancreatic cancer risk; and to investigate the associations in an independent study.

DESIGN

Reduced rank regression was applied to dietary data for 183,513 participants in the MEC. A food group pattern was extracted and simplified and applied to dietary data of 424,978 participants in the European Prospective Investigation into Cancer and Nutrition (EPIC) study. Dietary intake in both studies was assessed by using specially developed questionnaires. Multivariate Cox proportional hazards models were used to estimate relative risks for pancreatic cancer in the MEC (610 cases) and the EPIC (517 cases) studies.

RESULTS

The food group pattern consisted mainly of tea, fruit, cabbage, and wine. In the MEC, inverse associations with pancreatic cancer in smokers were observed for the food group pattern [relative risk: 0.59 (95% CI: 0.31, 1.12) when extreme quintiles were compared; P for trend = 0.03]. In the EPIC study, the simplified pattern was not associated with pancreatic cancer risk (P for trend = 0.78).

CONCLUSIONS

A food pattern associated with the intake of quercetin, kaempferol, and myricetin was associated with lower pancreatic cancer risk in smokers in a US-based population. However, failure to replicate the associations in an independent study weakens the conclusions and raises questions about the utility of food patterns for flavonols across populations.

Dietary glycaemic index, glycaemic load and breast cancer risk: a systematic review and meta-analysis

This systematic review aimed to examine if an association exists between dietary glycaemic index (GI) and glycaemic load (GL) intake and breast cancer risk. A systematic search was conducted in Medline and Embase and identified 14 relevant studies up to May 2008. Adjusted relative risk estimates comparing breast cancer risk for the highest versus the lowest category of GI/GL intake were extracted from relevant studies and combined in meta-analyses using a random-effects model. Combined estimates from six cohort studies show non-significant increased breast cancer risks for premenopausal women (relative risk (RR) 1.14, 95% CI 0.95–1.38) and postmenopausal women (RR 1.11, 95% CI 0.99–1.25) consuming the highest versus the lowest category of GI intake. Evidence of heterogeneity hindered analyses of GL and premenopausal risk, although most studies did not observe any significant association. Pooled cohort study results indicated no association between postmenopausal risk and GL intake (RR 1.03, 95% CI 0.94–1.12). Our findings do not provide strong support of an association between dietary GI and GL and breast cancer risk.

Dietary patterns, insulin resistance, and incidence of type 2 diabetes in the Whitehall II Study

OBJECTIVE

The aim of this study was to identify a dietary pattern associated with insulin resistance and investigate whether this pattern was prospectively associated with type 2 diabetes.

RESEARCH DESIGN AND METHODS

Analysis was based on 7,339 participants of the Whitehall II study. Dietary intake was measured using a 127-item food frequency questionnaire. We used the reduced rank regression method to determine dietary patterns using the homeostasis model assessment of insulin resistance as the intermediate or response variable. The association between the dietary pattern identified and incidence of type 2 diabetes was investigated using Cox proportional hazard regression models.

RESULTS

We identified a dietary pattern characterized by high consumption of low-calorie/diet soft drinks, onions, sugar-sweetened beverages, burgers and sausages, crisps and other snacks, and white bread and low consumption of medium-/high-fiber breakfast cereals, jam, French dressing/vinaigrette, and wholemeal bread. Higher dietary pattern scores were associated with increased risk of type 2 diabetes (hazard ratio for top quartile 2.95 [95% CI 2.19-3.97]; adjusted for age, sex, and energy misreporting). This relationship was attenuated after adjustment for ethnicity, employment grade, health behaviors (smoking, alcohol use, and physical activity) but remained significant after further adjustment for blood pressure and BMI (1.51 [1.10-2.09]).

CONCLUSIONS

A dietary pattern associated with insulin resistance predicts type 2 diabetes risk after adjustment for a range of confounders. This study adds to the evidence that dietary patterns are an important risk factor for type 2 diabetes.

Glycemic index, glycemic load, and cancer risk: a meta-analysis

BACKGROUND

Factors linked to glucose metabolism play an important role in the development of cancers, and both glycemic index (GI) and glycemic load (GL) have been investigated as potential etiologic factors.

OBJECTIVE

A meta-analysis was performed to explore the association between GI and GL and cancer risk from published studies.

DESIGN

A comprehensive, systematic bibliographic search of the medical literature was conducted to identify relevant studies. Case-control and cohort studies published before October 2007 that reported cancer risk estimates for GI and GL were included. Pooled relative risks (RRs) were estimated for breast, colorectal, endometrial, and pancreatic cancer.

RESULTS

Thirty-nine studies were included in the meta-analysis. The interquantile ranges of GL were significantly wider in case-control studies, most of which were conducted in European countries, than in cohort studies. Cohort studies that presented lower ranges of GL also reported lower risk estimates. Overall, both GL and GI were significantly associated with a greater risk of colorectal (summary RR = 1.26; 95% CI: 1.11, 1.44 and RR = 1.18; 95% CI: 1.05, 1.34, respectively) and endometrial (RR = 1.36; 95% CI: 1.14, 1.62 and RR = 1.22; 95% CI: 1.01, 1.49) cancer than of breast and pancreatic cancer. There was, however, a significant between-study heterogeneity for colorectal cancer (P < 0.0001). The association between GL and breast cancer disappeared when publication bias was taken into account. No association was found for pancreatic cancer.

CONCLUSION

This comprehensive meta-analysis of GI and GL and cancer risk suggested an overall direct association with colorectal and endometrial cancer.