Identification of Dietary Patterns Using Two Statistical Approaches and Their Association With Breast Cancer Risk: A Case-Control Study in Southern France

Dietary patterns, cooking methods and breast cancer risk in Mexico: An exploratory case-control study

Background: Nutrition has an important influence on the risk of developing breast cancer (BC). Dietary patterns can capture the complex interplay of nutrients and cooking methods can contribute to the presence of heterocyclic amines, which are potent mammary carcinogens. Research on dietary patterns, cooking methods, and their association with BC in Mexican women is scarce. Aim: To evaluate the association of dietary patterns and cooking methods with BC risk among women from the Northwest region of Mexico. Methods: This case-control study included 120 women. Eligible cases (n = 60) were diagnosed and biopsy-confirmed in the past 2 years. Control subjects (n = 60) were hospital and population-based. Dietary intake and cooking methods were respectively assessed through a food frequency questionnaire (FFQ) and the National Cancer Institute survey. We obtained dietary patterns from a K-means cluster analysis (CA), and multivariate logistic regression tested the association of dietary patterns and cooking methods with BC risk. Results: Prudent and caloric dietary patterns were identified. The caloric pattern was associated with BC risk (Model 1: ORadj: 5.07, 95%CI:1.44-17.84, p = 0.011; Model 2: ORadj: 4.99 (95%CI:1.39-17.92, p = 0.014). Intense frying, meat grilling and poultry resulted in a significant BC risk (Model 1: ORadj: 5.54,95%CI: 2.13-14.41), p < 0.001; Model 2: ORadj: 5.12, 95%CI: 1.83-14.31, p = 0.002). At Oestrogen exposure of <32 years, there was an association between dietary patterns and BC risk (ORadj: 4.69, 95%CI: 1.01-21.92, p = 0.049). The relationship between BC risk and cooking intensity was found in both strata of exposure to oestrogens: <32 years (ORadj: 3.72, 95%CI:1.04-13.33, p = 0.044), and ≥32 years (ORadj: 6.06, 95%CI:1.34-27.42, p = 0.019). Conclusions: A caloric dietary pattern rich in refined carbohydrates and saturated fat, and intense meat product cooking may increase the risk of BC in Mexican women.

High adherence to Western dietary pattern increases breast cancer risk (an EPIC-Spain study)

OBJECTIVE

To explore the association between three previously identified and validated dietary patterns (Western, Prudent and Mediterranean) and breast cancer risk by tumour subtype and menopausal status.

METHODS

Data from the Spanish cohort of the European Prospective Investigation into Cancer and Nutrition study provided epidemiological information (including diet and cancer incidence) from 24,892 women (639 breast cancer cases) recruited between 1992 and 1996. The associations between adherence to the three dietary patterns and breast cancer risk (overall and by tumour subtype) were explored by fitting multivariate Cox proportional hazards regression models stratified by region, among other variables. A possible interaction with menopausal status (changing over time) was explored.

RESULTS

No clear association of the Prudent and Mediterranean dietary patterns with breast cancer risk was found. When compared with women with a level of adherence to the Western diet in the first quartile, women with a level of adherence in the third (hazard ratio (95 % confidence interval) (HR(95%CI)):1.37 (1.07;1.77)) and fourth quartiles (1.37 (1.03;1.83)); p for curvature of splines = 0.016) showed a non-linear increased risk, especially postmenopausal women (HR (95 % CI) 1.30 (0.98;1.72) in the third and 1.42 (1.04;1.94) in the fourth quartiles; p for curvature of splines = 0.081) and for estrogen or progesterone receptor positive with human epidermal growth factor receptor 2 negative tumours (HR (95 % CI) 1.62 (1.10;2.38) and 1.71 (1.11;2.63) for the third and fourth quartiles respectively; p for curvature of splines = 0.013).

CONCLUSIONS

Intake of foods such as high-fat dairy products, red and processed meats, refined grains, sweets, caloric drinks, convenience food and sauces might be associated with a higher risk of breast cancer.

Dietary Patterns and Breast Cancer Risk in Black Urban South African Women: The SABC Study

A total of 396 breast cancer cases and 396 population-based controls from the South African Breast Cancer study (SABC) matched on age and demographic settings was included. Validated questionnaires were used to collect dietary and epidemiological data. Dietary patterns were derived using principal component analysis with a covariance matrix from 33 food groups. Odds ratios and 95% confidence intervals were estimated using conditional logistic regression. A traditional, a cereal-dairy breakfast and a processed food dietary pattern were identified, which together explained 40.3% of the total variance in the diet. After adjusting for potential confounders, the traditional dietary pattern and cereal-dairy breakfast dietary pattern were inversely associated with breast cancer risk (highest tertile versus lowest tertile) (OR = 0.72, 95%CI: 0.57-0.89, p-trend = 0.004 and OR = 0.73, 95%CI: 0.59-0.90, p-trend = 0.004, respectively). The processed food dietary pattern was not significantly associated with breast cancer risk. The results of this study show that a traditional dietary pattern and a cereal-dairy breakfast dietary pattern may reduce the risk of developing breast cancer in this population.

An updated systematic review and meta-analysis on adherence to mediterranean diet and risk of cancer

PURPOSE

The aim of current systematic review was to update the body of evidence on associations between adherence to the Mediterranean diet (MedDiet) and risk of cancer mortality, site-specific cancer in the general population; all-cause, and cancer mortality as well as cancer reoccurrence among cancer survivors.

METHODS

A literature search for randomized controlled trials (RCTs), case-control and cohort studies published up to April 2020 was performed using PubMed and Scopus. Study-specific risk estimates for the highest versus lowest adherence to the MedDiet category were pooled using random-effects meta-analyses. Certainty of evidence from cohort studies and RCTs was evaluated using the NutriGrade scoring system.

RESULTS

The updated search revealed 44 studies not identified in the previous review. Altogether, 117 studies including 3,202,496 participants were enclosed for meta-analysis. The highest adherence to MedDiet was inversely associated with cancer mortality (RRcohort: 0.87, 95% CI 0.82, 0.92; N = 18 studies), all-cause mortality among cancer survivors (RRcohort: 0.75, 95% CI 0.66, 0.86; N = 8), breast (RRobservational: 0.94, 95% CI 0.90, 0.97; N = 23), colorectal (RRobservational: 0.83, 95% CI 0.76, 0.90; N = 17), head and neck (RRobservational: 0.56, 95% CI 0.44, 0.72; N = 9), respiratory (RRcohort: 0.84, 95% CI 0.76, 0.94; N = 5), gastric (RRobservational: 0.70, 95% CI 0.61, 0.80; N = 7), bladder (RRobservational: 0.87, 95% CI 0.76, 0.98; N = 4), and liver cancer (RRobservational: 0.64, 95% CI 0.54, 0.75; N = 4). Adhering to MedDiet did not modify risk of blood, esophageal, pancreatic and prostate cancer risk.

CONCLUSION

In conclusion, our results suggest that highest adherence to the MedDiet was related to lower risk of cancer mortality in the general population, and all-cause mortality among cancer survivors as well as colorectal, head and neck, respiratory, gastric, liver and bladder cancer risks. Moderate certainty of evidence from cohort studies suggest an inverse association for cancer mortality and colorectal cancer, but most of the comparisons were rated as low or very low certainty of evidence.

A new ensemble modeling method for multivariate calibration of near infrared spectra

Ensemble modeling has gained increasing attention for improving the performance of quantitative models in near infrared (NIR) spectral analysis. Based on Monte Carlo (MC) resampling, least absolute shrinkage and selection operator (LASSO) and partial least squares (PLS), a new ensemble strategy named MC-LASSO-PLS is proposed for NIR spectral multivariate calibration. In this method, the training subsets for building the sub-models are generated by sampling from both samples and variables to ensure the diversity of the models. In detail, a certain number of samples as sample subsets are randomly selected from training set. Then, LASSO is used to shrink the variables of the sample subset to form the training subset, which is used to build the PLS sub-model. This process is repeated N times and N sub-models are obtained. Finally, the predictions of these sub-models are used to produce the final prediction by simple average. The prediction ability of the proposed method was compared with those of LASSO-PLS, MC-PLS and PLS models on the NIR spectra of corn, blend oil and orange juice samples. The superiority of MC-LASSO-PLS in prediction ability is demonstrated.

Dietary Patterns and Risk of Invasive Ductal and Lobular Breast Carcinomas: A Systematic Review and Meta-analysis

The histopathologic subtypes of breast cancer, including invasive ductal carcinoma (IDC) and invasive lobular carcinoma (ILC), differ in terms of risk factors, progression, and response to treatment. The PubMed/Medline, Web of Science, and Scopus databases were searched up to February 2020 for published studies on the association between dietary patterns (Western diet [WD] or Mediterranean diet [WD]) and the risk of IDC/ILC of breast. Multivariable adjusted relative risk (RR) and 95% confidence intervals (CIs) comparing the highest and lowest categories of WD and MD patterns were combined by using the random-effects meta-analyses. After searching the databases, 10 eligible studies on the association of diet and IDC (7 articles) and ILC (3 articles) were included in the analysis. A statistically significant adverse association was observed between MD and IDC in case-control studies (RR = 0.47; 95% CI, 0.39-0.55; I² = 85.1%; P < .001). However, the association was nonsignificant in cohort studies (RR = 0.98; 95% CI, 0.92-1.05; I² = 88.8%; P = .003). The pooled analysis also suggested a significant and direct association between the WD and the risk of IDC (RR = 1.36; 95% CI, 1.18-1.53; I² = 63.7%; P = .017). The risk of ILC for the highest compared to the lowest category of MD was highly protective (RR = 0.76; 95% CI, 0.64-0.87; I² = 89.2%; P < .001), and a marginally significant association was found between the WD and risk of ILC (RR = 1.45; 95% CI, 1.04-1.86), with no heterogeneity (I² = 0; P = .52). This meta-analysis provides supporting evidence for the association between MD decreased risk of IDC and ILC of the breast and the association between WD and increased risk of IDC and ILC. Further investigations are needed to better understand the reasons behind the etiologic mechanisms of how dietary patterns affect patients differently by common breast cancer subtypes, including IDC and ILC.

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 and Their Sociodemographic and Lifestyle Determinants in Switzerland: Results from the National Nutrition Survey menuCH

From a public health perspective, determinants of diets are crucial to identify, but they remain unclear in Switzerland. Hence, we sought to define current dietary patterns and their sociodemographic and lifestyle determinants using the national nutrition survey menuCH (2014⁻2015, n = 2057). First, we applied multiple factorial analysis and hierarchical clustering on the energy-standardised daily consumption of 17 food categories. Four dietary patterns were identified ("Swiss traditional": high intakes of dairy products and chocolate, n = 744; "Western 1": soft drinks and meat, n = 383; "Western 2": alcohol, meat and starchy, n = 444; and "Prudent": n = 486). Second, we used multinomial logistic regression to examine the determinants of the four dietary patterns: ten sociodemographic or lifestyle factors (sex, age, body mass index, language region, nationality, marital status, income, physical activity, smoking status, and being on a weight-loss diet) were significantly associated with the dietary patterns. Notably, belonging to the French- and Italian-speaking regions of Switzerland increased the odds of following a "Prudent" diet (Odds ratio [95% confidence interval]: 1.92 [1.45⁻2.53] and 1.68 [0.98⁻2.90], respectively) compared to the German-speaking regions. Our findings highlight the influence of sociodemographic and lifestyle parameters on diet and the particularities of the language regions of Switzerland. These results provide the basis for public health interventions targeted for population subgroups.

Associations of Dietary Patterns and Metabolic-Hormone Profiles with Breast Cancer Risk: A Case-Control Study

Breast cancer is the most diagnosed cancer in women worldwide. Studies regarding complex breast cancer aetiology are limited and the results are inconclusive. We investigated the associations between dietary patterns (DPs), metabolic-hormone profiles (M-HPs), and breast cancer risk. This case-control study involved 420 women aged 40⁻79 years from north-eastern Poland, including 190 newly-diagnosed breast cancer cases. The serum concentration of lipid components, glucose, and hormones (oestradiol, progesterone, testosterone, prolactin, cortisol, insulin) was marked in 129 post-menopausal women (82 controls, 47 cases). The food frequency consumption was collected using a validated 62-item food frequency questionnaire. A posteriori DPs or M-HPs were derived with a Principal Component Analysis (PCA). Three DPs: 'Non-Healthy', 'Prudent', and 'Margarine and Sweetened Dairy' and two M-HPs: 'Metabolic-Syndrome' and 'High-Hormone' were identified. The 'Polish-adapted Mediterranean Diet' ('Polish-aMED') score was calculated. The risk of breast cancer risk was three-times higher (odds ratio (OR): 2.90; 95% confidence interval (95% Cl): 1.62⁻5.21; p < 0.001) in the upper tertile of the 'Non-Healthy' pattern (reference: bottom tertile) and five-times higher (OR: 5.34; 95% Cl: 1.84⁻15.48; p < 0.01) in the upper tertile of the 'High-Hormone' profile (reference: bottom tertile). There was a positive association of 'Metabolic-Syndrome' profile and an inverse association of 'Polish-aMED' score with the risk of breast cancer, which disappeared after adjustment for confounders. No significant association between 'Prudent' or 'Margarine and Sweetened Dairy' DPs and cancer risk was revealed. Concluding, a pro-healthy diet is insufficient to reduce the risk of breast cancer in peri- and postmenopausal women. The findings highlight the harmful effect of the 'High-Hormone' profile and the 'Non-Healthy' dietary pattern on breast cancer risk. In breast cancer prevention, special attention should be paid to decreasing the adherence to the 'Non-Healthy' pattern by reducing the consumption of highly processed food and foods with a high content of sugar and animal fat. There is also a need to monitor the concentration of multiple sex hormones in the context of breast cancer risk.

Associations of Mediterranean Diet and a Posteriori Derived Dietary Patterns with Breast and Lung Cancer Risk: A Case-Control Study

Lung cancer in men and breast cancer in women are the most commonly diagnosed cancers in Poland and worldwide. Results of studies involving dietary patterns (DPs) and breast or lung cancer risk in European countries outside the Mediterranean Sea region are limited and inconclusive. This study aimed to develop a ‘Polish-adapted Mediterranean Diet’ (‘Polish-aMED’) score, and then study the associations between the ‘Polish-aMED’ score and a posteriori-derived dietary patterns with breast or lung cancer risk in adult Poles. This pooled analysis of two case-control studies involved 560 subjects (280 men, 280 women) aged 40–75 years from Northeastern Poland. Diagnoses of breast cancer in 140 women and lung cancer in 140 men were found. The food frequency consumption of 21 selected food groups was collected using a 62-item Food Frequency Questionnaire (FFQ)-6. The ‘Polish-adapted Mediterranean Diet’ score which included eight items—vegetables, fruit, whole grain, fish, legumes, nuts and seeds—as well as the ratio of vegetable oils to animal fat and red and processed meat was developed (range: 0–8 points). Three DPs were identified in a Principal Component Analysis: ‘Prudent’, ‘Non-healthy’, ‘Dressings and sweetened-low-fat dairy’. In a multiple logistic regression analysis, two models were created: crude, and adjusted for age, sex, type of cancer, Body Mass Index (BMI), socioeconomic status (SES) index, overall physical activity, smoking status and alcohol abuse. The risk of breast or lung cancer was lower in the average (3–5 points) and high (6–8 points) levels of the ‘Polish-aMED’ score compared to the low (0–2 points) level by 51% (odds ratio (OR): 0.49; 95% confidence interval (Cl): 0.30–0.80; p < 0.01; adjusted) and 63% (OR: 0.37; 95% Cl: 0.21–0.64; p < 0.001; adjusted), respectively. In the middle and upper tertiles compared to the bottom tertile of the ‘Prudent’ DP, the risk of cancer was lower by 38–43% (crude) but was not significant after adjustment for confounders. In the upper compared to the bottom tertile of the ‘Non-healthy’ DP, the risk of cancer was higher by 65% (OR: 1.65; 95% Cl: 1.05–2.59; p < 0.05; adjusted). In conclusion, the Polish adaptation of the Mediterranean diet could be considered for adults living in non-Mediterranean countries for the prevention of the breast or lung cancers. Future studies should explore the role of a traditional Mediterranean diet fitted to local dietary patterns of non-Mediterranean Europeans in cancer prevention.

Possible role of diet in cancer: systematic review and multiple meta-analyses of dietary patterns, lifestyle factors, and cancer risk

Context

Evidence of an association between dietary patterns derived a posteriori and risk of cancer has not been reviewed comprehensively.

Objective

The aim of this review was to investigate the relation between a posteriori-derived dietary patterns, grouped as healthy or unhealthy, and cancer risk. The relation between cancer risk and background characteristics associated with adherence to dietary patterns was also examined.

Data Sources

PubMed and Embase electronic databases were searched.

Study Selection

A total of 93 studies including over 85 000 cases, 100 000 controls, and 2 000 000 exposed individuals were selected.

Data Extraction

Data were extracted from each identified study using a standardized form by two independent authors.

Results

The most convincing evidence (significant results from prospective cohort studies) supported an association between healthy dietary patterns and decreased risk of colon and breast cancer, especially in postmenopausal, hormone receptor-negative women, and an association between unhealthy dietary patterns and increased risk of colon cancer. Limited evidence of a relation between an unhealthy dietary pattern and risk of upper aerodigestive tract, pancreatic, ovarian, endometrial, and prostatic cancers relied only on case-control studies. Unhealthy dietary patterns were associated with higher body mass index and energy intake, while healthy patterns were associated with higher education, physical activity, and less smoking. Potential differences across geographical regions require further evaluation.

Conclusions

The results suggest a potential role of diet in certain cancers, but the evidence is not conclusive and may be driven or mediated by lifestyle factors.

A review of adherence to the Mediterranean diet and breast cancer risk according to estrogen- and progesterone-receptor status and HER2 oncogene expression

Background

Previous observational studies and systematic reviews have suggested that adherence to the Mediterranean diet is associated with a reduced risk of breast cancer, but have not examined associations with molecular subtypes of breast cancer. The current review examines the association with adherence to the Mediterranean diet and risk of breast cancer according to molecular subtypes.

Methods

Bibliographic searches were conducted in PubMed and CINAHL using relevant MeSH search terms and Boolean algebra commands.

Results

Six cohort studies and one case-control study have examined adherence with the Mediterranean diet and risk of breast cancer according to estrogen-receptor (ER) and progesterone-receptor (PR) status and human epidermal growth factor 2 (HER2) oncogene expression. Taken overall, studies suggest that the Mediterranean dietary pattern is inversely associated with breast cancer risk in postmenopausal women, and that the inverse association is somewhat stronger among ER- tumors. Although there is a suggestion that the Mediterranean diet is inversely associated with PR- tumors and with ER-/PR-/HER2- ("triple negative" tumors), results to date have been mixed and the number of studies that have examined associations with this dietary pattern among tumors characterized by multiple molecular subtypes remains small.

Conclusions

The results of this systematic review suggest that consumption of a Mediterranean diet pattern is associated with a reduced risk of postmenopausal breast cancer, particularly among ER- tumors. Additional cohort studies that have sufficient sample sizes and long-term follow-up are warranted to identify sizeable numbers of invasive breast cancer cases, thereby allowing for characterization of the tumors by molecular subtype.

Adherence to Mediterranean Diet and Risk of Cancer: An Updated Systematic Review and Meta-Analysis

The aim of the present systematic review and meta-analysis was to gain further insight into the effects of adherence to Mediterranean Diet (MedD) on risk of overall cancer mortality, risk of different types of cancer, and cancer mortality and recurrence risk in cancer survivors. Literature search was performed using the electronic databases PubMed, and Scopus until 25 August 2017. We included randomized trials (RCTs), cohort (for specific tumors only incidence cases were used) studies, and case-control studies. Study-specific risk ratios, hazard ratios, and odds ratios (RR/HR/OR) were pooled using a random effects model. Observational studies (cohort and case-control studies), and intervention trials were meta-analyzed separately. The updated review process showed 27 studies that were not included in the previous meta-analysis (total number of studies evaluated: 83 studies). An overall population of 2,130,753 subjects was included in the present update. The highest adherence score to a MedD was inversely associated with a lower risk of cancer mortality (RRcohort: 0.86, 95% CI 0.81 to 0.91, I² = 82%; n = 14 studies), colorectal cancer (RRobservational: 0.82, 95% CI 0.75 to 0.88, I² = 73%; n = 11 studies), breast cancer (RRRCT: 0.43, 95% CI 0.21 to 0.88, n = 1 study) (RRobservational: 0.92, 95% CI 0.87 to 0.96, I² = 22%, n = 16 studies), gastric cancer (RRobservational: 0.72, 95% CI 0.60 to 0.86, I² = 55%; n = 4 studies), liver cancer (RRobservational: 0.58, 95% CI 0.46 to 0.73, I² = 0%; n = 2 studies), head and neck cancer (RRobservational: 0.49, 95% CI 0.37 to 0.66, I² = 87%; n = 7 studies), and prostate cancer (RRobservational: 0.96, 95% CI 0.92 to 1.00, I² = 0%; n = 6 studies). Among cancer survivors, the association between the adherence to the highest MedD category and risk of cancer mortality, and cancer recurrence was not statistically significant. Pooled analyses of individual components of the MedD revealed that the protective effects appear to be most attributable to fruits, vegetables, and whole grains. The updated meta-analysis confirms an important inverse association between adherence to a MedD and cancer mortality and risk of several cancer types, especially colorectal cancer. These observed beneficial effects are mainly driven by higher intakes of fruits, vegetables, and whole grains. Moreover, we were able to report for the first time a small decrease in breast cancer risk (6%) by pooling seven cohort studies.

Reproducibility of data-driven dietary patterns in two groups of adult Spanish women from different studies

The objective of the present study was to assess the reproducibility of data-driven dietary patterns in different samples extracted from similar populations. Dietary patterns were extracted by applying principal component analyses to the dietary information collected from a sample of 3550 women recruited from seven screening centres belonging to the Spanish breast cancer (BC) screening network (Determinants of Mammographic Density in Spain (DDM-Spain) study). The resulting patterns were compared with three dietary patterns obtained from a previous Spanish case-control study on female BC (Epidemiological study of the Spanish group for breast cancer research (GEICAM: grupo Español de investigación en cáncer de mama)) using the dietary intake data of 973 healthy participants. The level of agreement between patterns was determined using both the congruence coefficient (CC) between the pattern loadings (considering patterns with a CC≥0·85 as fairly similar) and the linear correlation between patterns scores (considering as fairly similar those patterns with a statistically significant correlation). The conclusions reached with both methods were compared. This is the first study exploring the reproducibility of data-driven patterns from two studies and the first using the CC to determine pattern similarity. We were able to reproduce the EpiGEICAM Western pattern in the DDM-Spain sample (CC=0·90). However, the reproducibility of the Prudent (CC=0·76) and Mediterranean (CC=0·77) patterns was not as good. The linear correlation between pattern scores was statistically significant in all cases, highlighting its arbitrariness for determining pattern similarity. We conclude that the reproducibility of widely prevalent dietary patterns is better than the reproducibility of more population-specific patterns. More methodological studies are needed to establish an objective measurement and threshold to determine pattern similarity.

Dietary patterns in the French adult population: a study from the second French national cross-sectional dietary survey (INCA2) (2006-2007)

Identification and characterisation of dietary patterns are needed to define public health policies to promote better food behaviours. The aim of this study was to identify the major dietary patterns in the French adult population and to determine their main demographic, socio-economic, nutritional and environmental characteristics. Dietary patterns were defined from food consumption data collected in the second French national cross-sectional dietary survey (2006-2007). Non-negative-matrix factorisation method, followed by a cluster analysis, was implemented to derive the dietary patterns. Logistic regressions were then used to determine their main demographic and socio-economic characteristics. Finally, nutritional profiles and contaminant exposure levels of dietary patterns were compared using ANOVA. Seven dietary patterns, with specific food consumption behaviours, were identified: 'Small eater', 'Health conscious', 'Mediterranean', 'Sweet and processed', 'Traditional', 'Snacker' and 'Basic consumer'. For instance, the Health-conscious pattern was characterised by a high consumption of low-fat and light products. Individuals belonging to this pattern were likely to be older and to have a better nutritional profile than the overall population, but were more exposed to many contaminants. Conversely, individuals of Snacker pattern were likely to be younger, consumed more highly processed foods, had a nutrient-poor profile but were exposed to a limited number of food contaminants. The study identified main dietary patterns in the French adult population with distinct food behaviours and specific demographic, socio-economic, nutritional and environmental features. Paradoxically, for better dietary patterns, potential health risks cannot be ruled out. Therefore, this study demonstrated the need to conduct a risk-benefit analysis to define efficient public health policies regarding diet.

Evaluating the Applicability of Data-Driven Dietary Patterns to Independent Samples with a Focus on Measurement Tools for Pattern Similarity

BACKGROUND

Diet is a key modifiable risk for many chronic diseases, but it remains unclear whether dietary patterns from one study sample are generalizable to other independent populations.

OBJECTIVE

The primary objective of this study was to assess whether data-driven dietary patterns from one study sample are applicable to other populations. The secondary objective was to assess the validity of two criteria of pattern similarity.

METHODS

Six dietary patterns-Western (n=3), Mediterranean, Prudent, and Healthy- from three published studies on breast cancer were reconstructed in a case-control study of 973 breast cancer patients and 973 controls. Three more internal patterns (Western, Prudent, and Mediterranean) were derived from this case-control study's own data.

STATISTICAL ANALYSIS

Applicability was assessed by comparing the six reconstructed patterns with the three internal dietary patterns, using the congruence coefficient (CC) between pattern loadings. In cases where any pair met either of two commonly used criteria for declaring patterns similar (CC ≥0.85 or a statistically significant [P<0.05] Pearson correlation), then the true similarity of those two dietary patterns was double-checked by comparing their associations to risk for breast cancer, to assess whether those two criteria of similarity are actually reliable.

RESULTS

Five of the six reconstructed dietary patterns showed high congruence (CC >0.9) to their corresponding dietary pattern derived from the case-control study's data. Similar associations with risk for breast cancer were found in all pairs of dietary patterns that had high CC but not in all pairs of dietary patterns with statistically significant correlations.

CONCLUSIONS

Similar dietary patterns can be found in independent samples. The P value of a correlation coefficient is less reliable than the CC as a criterion for declaring two dietary patterns similar. This study shows that diet scores based on a particular study are generalizable to other populations.

Adherence to Mediterranean diet and risk of cancer: an updated systematic review and meta-analysis of observational studies

The aim of the present systematic review and meta-analysis of observational studies was to gain further insight into the effects of adherence to Mediterranean Diet (MD) on overall cancer mortality, incidence of different types of cancer, and cancer mortality risk in cancer survivors. Literature search was performed using the electronic databases PubMed, and EMBASE until 2 July 2015. We included either cohort (for specific tumors only incidence cases were used) or case-control studies. Study specific risk ratios, hazard ratios, and odds ratios (RR/HR/OR) were pooled using a random effect model. The updated review process showed 23 observational studies that were not included in the previous meta-analysis (total number of studies evaluated: 56 observational studies). An overall population of 1,784,404 subjects was included in the present update. The highest adherence score to an MD was significantly associated with a lower risk of all-cause cancer mortality (RR: 0.87, 95% CI 0.81-0.93, I(2) = 84%), colorectal cancer (RR: 0.83, 95% CI 0.76-0.89, I(2) = 56%), breast cancer (RR: 0.93, 95% CI 0.87-0.99, I(2) =15%), gastric cancer (RR: 0.73, 95% CI 0.55-0.97, I(2) = 66%), prostate cancer (RR: 0.96, 95% CI 0.92-1.00, I(2) = 0%), liver cancer (RR: 0.58, 95% CI 0.46-0.73, I(2) = 0%), head and neck cancer (RR: 0.40, 95% CI 0.24-0.66, I(2) = 90%), pancreatic cancer (RR: 0.48, 95% CI 0.35-0.66), and respiratory cancer (RR: 0.10, 95% CI 0.01-0.70). No significant association could be observed for esophageal/ovarian/endometrial/and bladder cancer, respectively. Among cancer survivors, the association between the adherence to the highest MD category and risk of cancer mortality, and cancer recurrence was not statistically significant. The updated meta-analyses confirm a prominent and consistent inverse association provided by adherence to an MD in relation to cancer mortality and risk of several cancer types.

Does a Mediterranean-Type Diet Reduce Cancer Risk?

Overall cancer incidence has been observed to be lower in Mediterranean countries compared to that in Northern countries, such as the UK, and the USA. There is increasing evidence that adherence to a Mediterranean dietary pattern correlates with reduced risk of several cancer types and cancer mortality. In addition, specific aspects of the Mediterranean diet, such as high consumption of fruit and vegetables, whole grains, and low processed meat intake, are inversely associated with risk of tumor pathogenesis at different cancer sites. The purpose of this review is to summarize the available evidence regarding the association between the Mediterranean diet and cancer risk from clinical trials, prospective cohort studies, and case-control studies. Furthermore, we focused on the different definitions of a Mediterranean diet in an attempt to assess their efficiency. Observational studies provide new evidence suggesting that high adherence to a Mediterranean diet is associated with reduced risk of overall cancer mortality as well as a reduced risk of incidence of several cancer types (especially cancers of the colorectum, aerodigestive tract, breast, stomach, pancreas, prostate, liver, and head and neck).

Adherence to Mediterranean diet and risk of cancer: a systematic review and meta-analysis of observational studies

The aim of this research study was to meta-analyze the effects of adherence to Mediterranean diet (MD) on overall cancer risk, and different cancer types. Literature search was performed using the electronic databases MEDLINE, SCOPUS and EMBASE until January 10, 2014. Inclusion criteria were cohort or case-control studies. Study specific risk ratios (RRs) were pooled using a random effect model by the Cochrane software package Review Manager 5.2. Twenty-one cohort studies including 1,368,736 subjects and 12 case-control studies with 62,725 subjects met the objectives and were enclosed for meta-analyses. The highest adherence to MD category resulted in a significantly risk reduction for overall cancer mortality/incidence (cohort; RR: 0.90, 95% CI 0.86-0.95, p < 0.0001; I(2) = 55%), colorectal (cohort/case-control; RR: 0.86, 95% CI 0.80-0.93, p < 0.0001; I(2) = 62%], prostate (cohort/case-control; RR: 0.96, 95% CI 0.92-0.99, p = 0.03; I(2) = 0%) and aerodigestive cancer (cohort/case-control; RR: 0.44, 95% CI 0.26-0.77, p = 0.003; I(2) = 83%). Nonsignificant changes could be observed for breast cancer, gastric cancer and pancreatic cancer. The Egger regression tests provided limited evidence of substantial publication bias. High adherence to a MD is associated with a significant reduction in the risk of overall cancer mortality (10%), colorectal cancer (14%), prostate cancer (4%) and aerodigestive cancer (56%).

Breast cancer and dietary patterns: a systematic review

This systematic review collates research on the topic of dietary patterns and breast cancer risks. The literature search targeted epidemiological studies published up to December 2012 and was conducted using the Medline (U.S. National Library of Medicine, Bethesda MD, USA) and Lilacs (Latin American and Caribbean Health Sciences, São Paulo, Brazil) databases. The following search terms were used: breast cancer, breast neoplasm, breast carcinoma, diet, food, eating habits, dietary patterns, factor analysis, and principal component analysis. Only studies that used factor analysis techniques and/or principal component analysis were eligible, and a total of 26 studies were included. The findings of these studies suggest the Mediterranean dietary pattern and diets composed largely of vegetables, fruit, fish, and soy are associated with a decreased risk of breast cancer. There was no evidence of an association between traditional dietary patterns and risk of breast cancer, and only one study showed a significant increase in risk associated with the Western dietary pattern. Diets that include alcoholic beverages may be associated with increased risk.

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

BACKGROUND

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

OBJECTIVE

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

DESIGN

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

RESULTS

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

CONCLUSION

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

Is Usual Dietary Pattern Related to the Risk of Developing Breast Cancer?

Dietary patterns capture total diet providing a more comprehensive understanding of the effect of diet on chronic disease risk. Dietary patterns have been associated with several chronic diseases, including cardiovascular disease and selected cancers; however, the association with breast cancer remains unclear. The objective of this review was to examine critically the most recent literature on dietary patterns and breast cancer and report on current results, new developments, and future directions. Seven case-control and cohort studies from multiple countries have been published during the previous year (2011-2012). Many have analyzed a posteriori dietary patterns via factor and principal component analysis. Whereas results remain mixed, the majority of studies indicate healthier patterns decrease breast cancer risk, although patterns higher in meat and alcohol increase risk. Future studies that examine the associations between diet and tumor subtypes and collect dietary data at younger ages and, if possible, longitudinally would be beneficial.