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

Dietary patterns and risk of oral and oropharyngeal cancers: A systematic review and meta-analysis

Systematic evaluation of evidence assessing the role of dietary patterns on oral and oropharyngeal (OOP) cancer risk can provide a better understanding of their relationship. This systematic review of observational studies aimed to integrate the most recent evidence on the relationship between posteriori and priori dietary patterns and risk of development of OOP cancers. Studies were retrieved from Embase, PubMed, and Web of Science, and a total of 22 publications were included in the systematic review, of which 17 were included in the meta-analysis. Summary risk was estimated for highest versus lowest intakes of most common identified food groups and risk of OOP cancers using the random effect, generic inverse variance method. The quality of the included studies was assessed using the Newcastle-Ottawa Quality Assessment Scale (NOS) for Case-Control and Cohort studies. As per pooled analysis, consumption of healthy patterns may decrease the risk of OOP cancers by 43 %, and that of western patterns may increase this risk by 62 %. The pooling of data from ten studies analysing priori patterns and OOP cancers shows that the Mediterranean diet and diverse diet reduce the risk of such cancers, and a pro-inflammatory diet escalates the risk. On NOS, 11 studies were good in quality and 11 were moderate. Adopting a diet rich in fruits and vegetables and low intake of snacks and animal fats can potentially reduce the likelihood of developing OOP cancers. Encouraging Mediterranean diet, diverse diet and anti-inflammatory food components would be beneficial in the prevention and control of OOP cancers.

Are Major a Posteriori Dietary Patterns Reproducible in the Italian Population? A Systematic Review and Quantitative Assessment

Although a posteriori dietary patterns (DPs) naturally reflect actual dietary behavior in a population, their specificity limits generalizability. Among other issues, the absence of a standardized approach to analysis have further hindered discovery of genuinely reproducible DPs across studies from the same/similar populations. A systematic review on a posteriori DPs from principal component analysis or exploratory factor analysis (EFA) across study populations from Italy provides the basis to explore assessment and drivers of DP reproducibility in a case study of epidemiological interest. First to our knowledge, we carried out a qualitative (i.e., similarity plots built on text descriptions) and quantitative (i.e., congruence coefficients, CCs) assessment of DP reproducibility. The 52 selected articles were published in 2001-2022 and represented dietary habits in 1965-2022 from 70% of the Italian regions; children/adolescents, pregnancy/breastfeeding women, and elderly were considered in 15 articles. The included studies mainly derived EFA-based DPs on food groups from food frequency questionnaires and were of "good quality" according to standard scales. Based on text descriptions, the 186 identified DPs were collapsed into 113 (69 food-based and 44 nutrient-based) apparently different DPs (39.3% reduction), later summarized along with the 3 "Mixed-Salad/Vegetable-based Patterns," "Pasta-and-Meat-oriented/Starchy Patterns," and "Dairy Products" and "Sweets/Animal-based Patterns" groups, by matching similar food-based and nutrient-based groups of collapsed DPs. Based on CCs (215 CCs, 68 DPs, 18 articles using the same input lists), all pairs of DPs showing the same/similar names were at least "fairly similar" and ∼81% were "equivalent." The 30 "equivalent" DPs ended up into 6 genuinely different DPs (80% reduction) that targeted fruits and (raw) vegetables, pasta and meat combined, and cheese and deli meats. Such reduction reflects the same study design, list of input variables, and DP identification method followed across articles from the same groups. This review was registered at PROSPERO as CRD42022341037.

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.

Meal-specific dietary patterns and biomarkers of insulin resistance in a sample of Iranian adults: a cross-sectional study

Current research emphasizes the habitual dietary pattern without differentiating eating occasions. We aimed to assess meal-specific dietary patterns and insulin resistance indicators. This cross-sectional study was conducted on 825 Iranian adults. Dietary data were recorded by three 24-h dietary recalls. Dietary patterns were identified using principal component analysis (PCA) on main meals and an afternoon snack. Anthropometric measurements, blood pressure, and laboratory investigation, fasting plasma glucose (FPG), triglyceride, insulin, c-reactive protein (CRP) were done. Homeostatic model assessment for insulin resistance and sensitivity (HOMA-IR and HOMA-IS), Triglycerides and glucose (TyG-index), and Lipid accommodation product index were calculated. We used multivariate analysis of variance (MANOVA) analysis. Two major dietary patterns at the main meals and the afternoon were identified. Higher adherence to "Bread, vegetable, and cheese" dietary pattern at breakfast was related to lower FPG, and "Oil, egg, and cereals" showed a direct association with body mass index, FPG, and TyG-index at breakfast. The "Western" pattern in lunch and dinner directly related to waist circumference (WC) and body mass index, however, it was inversely related to HOMA-IS. This pattern at dinner was related to higher CRP. Higher adherence to "bread, cereals, and oil" pattern at afternoon snack was associated with a lower WC. These results indicated that unhealthy meal-specific dietary patterns are associated with a greater chance of obesity and insulin resistance risk. However, "Bread, vegetable, and cheese" dietary pattern at breakfast was related to lower FPG, and "bread, cereals, and oil" pattern in the afternoon was associated with lower WC.

Characterization of Maternal Psychosocial Stress During Pregnancy: The Healthy Start Study

Objective

To capture multidimensional maternal psychosocial stress using responses from the Edinburgh Postnatal Depression Scale (EPDS) and Cohen's Perceived Stress Scale (PSS) administered during pregnancy, and to identify sociodemographic, biological, and health behavioral correlates of the stress domains.

Methods

Using data from 1,079 pregnant women, we implemented principal component analysis on EPDS and PSS responses and retained factors based on the Scree plot and Eigenvalues >1. We then used linear regression to identify perinatal correlates of each domain.

Results

We identified three stress domains: "Feeling Overwhelmed," "Anhedonia," and "Lack of Control," which accounted for 10.6% of variance in questionnaire responses. In multivariable analyses, household income ≤$70,000 (β = 0.21 confidence interval [95% CI: 0.05-0.39]), primiparity (0.36 [0.02-0.71]), inadequate (0.21 [0.04-0.39]) or excessive gestational weight gain (0.27 [0.11-0.42]), and Healthy Eating Index (HEI) score ≤57 (0.14 [0.00-0.28]) were associated with Feeling Overwhelmed. Older age (0.02 [0.00-0.03] per 1-year), Hispanic ethnicity (0.19 [0.00-0.38]), and HEI score ≤57 (0.15 [0.02-0.28]) were associated with Anhedonia. Non-Hispanic Black race/ethnicity (0.37 [0.10-0.63]), not having graduated from college (0.16 [-0.02 to 0.35]), having a partner born outside the United States (0.17 [-0.02 to 0.37]), household size of ≥5 persons (0.21 [-0.02 to 0.37]), receiving public assistance (0.18 [-0.02 to 0.37]), and prenatal smoking (0.32 [0.05-0.59]) were associated with Lack of Control.

Conclusions

Three domains of maternal psychosocial stress during pregnancy (Feeling Overwhelmed, Anhedonia, and Lack of Control) were differentially related to sociodemographic, biological, and health behavioral characteristics that may be targets for interventions to ameliorate stress in pregnant women.

Clinical Trial Registry

: The Healthy Start study is registered as an observational study at clinicaltrials.gov (NCT #002273297).

Meal-specific dietary patterns and their contribution to habitual dietary patterns in the Iranian population

Recent studies have focused on habitual intake without addressing meal-specific intakes. We aimed to identify meal-specific dietary patterns and their contribution to habitual dietary patterns. This cross-sectional study was conducted on 838 adults, both sexes who attended the health centres in Tehran. Dietary data were recorded by three 24-h dietary recalls (24hDR). Dietary patterns were identified by using principal component analysis on meal-specific and overall food intakes. Intraclass correlation (ICC) was used as a measurement of consistency across meals and days. Correlation analysis and linear regression (partial R2) were used for meals contribution. Four habitual dietary patterns were derived from average dietary intake of 3-d 24hDR labelled as 'Western', 'Healthy', 'Traditional' and 'Legume and broth'. Also, we identified two major dietary patterns on each meal level (factor 1 and 2 for breakfast, lunch, afternoon snack and dinner). The highest contribution of energy intake was observed in lunch (25·7 %), followed by dinner (20·81 %). Consistency of food groups was the highest across days (ICC tea = 0·58) and breakfasts (ICC tea = 0·60). Dinner had a strong correlation coefficient with the 'Western' habitual dietary pattern then followed by lunch. Similarly, dinner and lunch contributed the most (r and partial R2) to the 'Western' habitual dietary pattern. Our results suggest that habitual dietary patterns to several extents are formed at meal levels, and dinner has a greater contribution to the habitual dietary patterns in Iranian people. This may help planning for local dietary guidelines according to the time of eating to promote public health.

Relative Validity and Reproducibility of a Food Frequency Questionnaire for Assessing Dietary Patterns and Food Group Intake in Older New Zealand Adults: The Researching Eating, Activity, and Cognitive Health Study

BACKGROUND

Dietary pattern analysis considers the overall dietary intake and combinations of foods eaten. Valid and reproducible tools for determining dietary patterns are necessary to assess diet-disease relationships.

OBJECTIVE

This study evaluated the relative validity and reproducibility of the Researching Eating, Activity, and Cognitive Health (REACH) Study food frequency questionnaire (FFQ) specifically designed to identify dietary patterns in older adults.

DESIGN

A subset of participants from the REACH study completed two identical 109-item FFQs 1 month apart (FFQ1 and FFQ2) to assess reproducibility and a 4-day food record between FFQ administrations to assess relative validity. Foods from each dietary assessment tool were assigned to 57 food groups. Principal component analysis was applied to the food group consumption reported in each dietary assessment tool to derive dietary patterns.

PARTICIPANTS AND SETTING

Dietary data were collected (2018 and 2019) from a subset of the REACH study (n = 294, 37% men) aged 65 to 74 years, living in Auckland, New Zealand.

MAIN OUTCOME MEASURES

Daily intakes of 57 food groups and dietary patterns of older adults participating in REACH living in New Zealand.

STATISTICAL ANALYSIS

Agreement of dietary pattern loadings were assessed using Tucker's congruence coefficient. Agreement of dietary pattern scores and food group intakes were assessed using Spearman correlation coefficients (acceptable correlation rho = 0.20 to 0.49), weighted kappa statistic (acceptable statistic κ_w = 0.20 to 0.60), and Bland-Altman analysis, including mean difference, limits of agreement, plots, and slope of bias.

RESULTS

Three similar dietary patterns were identified from each dietary assessment tool: Mediterranean style, Western, and prudent. Congruence coefficients between factor loadings ranged from 0.54 to 0.80. Correlations of dietary pattern scores ranged from 0.47 to 0.59 (reproducibility) and 0.33 to 0.43 (validity) (all P values < 0.001); weighted kappa scores from 0.40 to 0.48 (reproducibility) and 0.27 to 0.37 (validity); limits of agreement from ± 1.79 to ± 2.09 (reproducibility) and ± 2.09 to ± 2.27 (validity); a negative slope of bias was seen in the prudent pattern for reproducibility and validity (P < 0.001).

CONCLUSIONS

The REACH FFQ generated dietary patterns with acceptable reproducibility and relative validity and therefore can be used to examine associations between dietary patterns and health outcomes in older New Zealand adults.

A review of statistical methods for dietary pattern analysis

Background

Dietary pattern analysis is a promising approach to understanding the complex relationship between diet and health. While many statistical methods exist, the literature predominantly focuses on classical methods such as dietary quality scores, principal component analysis, factor analysis, clustering analysis, and reduced rank regression. There are some emerging methods that have rarely or never been reviewed or discussed adequately.

Methods

This paper presents a landscape review of the existing statistical methods used to derive dietary patterns, especially the finite mixture model, treelet transform, data mining, least absolute shrinkage and selection operator and compositional data analysis, in terms of their underlying concepts, advantages and disadvantages, and available software and packages for implementation.

Results

While all statistical methods for dietary pattern analysis have unique features and serve distinct purposes, emerging methods warrant more attention. However, future research is needed to evaluate these emerging methods’ performance in terms of reproducibility, validity, and ability to predict different outcomes.

Conclusion

Selection of the most appropriate method mainly depends on the research questions. As an evolving subject, there is always scope for deriving dietary patterns through new analytic methodologies.

Data-Driven Dietary Patterns and Diet Quality Scores: Reproducibility and Consistency in Sex and Age Subgroups of Poles Aged 15-65 Years

This study aimed to assess: (i) the test–retest reproducibility of identification of data-driven dietary patterns (DPs) derived using a Principal Component Analysis (PCA) and hypothesis-driven DPs (diet quality scores); (ii) the consistency of data-driven DPs with diet quality scores in sex and age subgroups of Poles aged 15–65 years. The study involved 504 subjects (55.6% of females). Data on food consumption frequency (33 food items) were collected twice with a two-week interval using the Dietary Habits and Nutrition Beliefs Questionnaire (KomPAN^®) in a self-administered version (test and retest). Two major data-driven DPs (‘Prudent’ and ‘Western’) were identified in the total sample, sex groups and four age groups separately from test and retest data. Two diet quality scores were analysed: Pro-Healthy-Diet-Index-10 (pHDI-10) and Non-Healthy-Diet-Index-14 (nHDI-14). Tucker’s congruence coefficient indicated fair-to-good similarity of data-driven DPs between test and retest for all study subgroups, except for males. Across study subgroups, the intraclass correlation coefficient (ICC) between the test and retest ranged from 0.56 to 0.86 for ‘Prudent’ DP and 0.57 to 0.82 for ‘Western’ DP, with the lowest values in males. The ICC (test vs. retest) ranged from 0.84 to 0.88 for pHDI-10 and 0.75 to 0.88 for nHDI-14. Comparing the data-driven DPs and diet quality scores, the Spearman’s correlations ranged from 0.63 to 0.93 between ‘Prudent’ DP and pHDI-10, and from 0.60 to 0.81 between ‘Western’ DP and nHDI-14. The test–retest reproducibility of data-driven DPs and diet quality scores and their consistency were acceptable in most of the study subgroups, with a tendency to be higher for pro-health than unhealthy DPs. Data-driven DPs were more reproducible in females than males. The reproducibility of diet quality scores tended to be better in males than females and was the highest in 25–44-year-olds. The KomPAN^® questionnaire can be recommended to use data-driven DPs and diet quality scores to describe the habitual diet in people aged 15–65 years.

Reproducibility of A Posteriori Dietary Patterns across Time and Studies: A Scoping Review

Few studies have considered if a posteriori dietary patterns (DPs) are generalizable across different centers or studies, or if they are consistently seen over time. To date, no systematic search of the literature on these topics has been carried out. A scoping review was conducted through a systematic search on the PubMed database. In the current review, we included the 34 articles examining the extent to which a posteriori DPs were consistently seen: 1) across centers from the same study or across different studies potentially representing different populations or countries (here indicated as cross-study reproducibility) and 2) over longer time periods (i.e., ≥2 y) (here indicated as stability over time). Selected articles (published in 1981-2019, 32% from 2010 onwards) were based on observational studies, mostly from Europe and North America. Five articles were based on children and/or adolescents and 14 articles included adults (2 men; 12 women, of whom 3 were pregnant women). A posteriori DPs were mostly derived (32 articles) with principal component or factor analyses. Among the 9 articles assessing DP reproducibility across studies (number of centers/studies: 2-27; median: 3), 5 provided a formal assessment using statistical methods (4 index-based approaches of different complexity, 1 statistical model). A median of 4 DPs was reproduced across centers/studies (range: 1-7). Among the 25 articles assessing DP stability over time (number of time-occasions: 2-6; median: 3), 19 provided a formal assessment with statistical methods (17 index-based and/or test-based approaches, 1 statistical model, 1 with both strategies). The number and composition of DPs remained mostly stable over time. Based on the limited evidence collected, most identified DPs showed good reproducibility across studies and stability over time. However, when present within the single studies, the criteria for the formal assessment of cross-study reproducibility or stability over time were generally very basic.

Mediterranean dietary pattern is associated with lower incidence of premenopausal breast cancer in the Seguimiento Universidad de Navarra (SUN) Project

OBJECTIVE

Due to the growing interest in the role of dietary patterns (DPs) on chronic diseases, we assessed the association between a posteriori identified DPs in the Seguimiento Universidad de Navarra (SUN) Project - a prospective cohort study in a Mediterranean country - and breast cancer (BC) risk.

DESIGN

DPs were ascertained through a principal component analysis based on 31 predefined food groups. BC cases were initially identified through self-report or, if deceased, from death certificates or by notification by the next kin. Women reporting BC were asked to provide a copy of their medical report and diagnoses for confirmation purposes. We fitted Cox regression models to assess the association between adherence to the identified DPs and BC risk.

SETTING

Spanish university graduates.

PARTICIPANTS

We included 10 713 young and middle-aged - mainly premenopausal - women.

RESULTS

After a median follow-up of 10·3 years, we identified 100 confirmed and 168 probable incident BC cases. We described two major DPs: 'Western dietary pattern' (WDP) and 'Mediterranean dietary pattern' (MDP). A higher adherence to a WDP was associated with an increased risk of overall BC (multivariable-adjusted HR for confirmed BC Q4 v. Q1 1·70; 95 % CI 0·93, 3·12; P for trend = 0·045). Contrarily, adherence to a MDP was inversely associated with premenopausal BC (multivariable-adjusted HR Q4 v. Q1 0·33; 95 % CI 0·12, 0·91). No significant associations were observed for postmenopausal BC.

CONCLUSIONS

Whereas a higher adherence to the WDP may increase the risk of BC, a higher adherence to the MDP may decrease the risk of premenopausal BC.

Dietary Habits of Saharawi Type II Diabetic Women Living in Algerian Refugee Camps: Relationship with Nutritional Status and Glycemic Profile

Diabetes is one of the main health problems among Saharawi refugees living in Algerian camps, especially for women. As is known, diet plays an important role in the management of diabetes. However, the dietary habits of Saharawi diabetic women are unknown. Therefore, we investigated the dietary habits and established their relationship with the nutritional status and glycemic profile of such women. We recruited 65 Saharawi type II diabetic women taking orally glucose-lowering drugs only. Dietary habits were investigated using qualitative 24 h recall carried out over three non-consecutive days. Anthropometric measurements were taken and blood parameters were measured. About 80% of the women were overweight and about three out of four women had uncompensated diabetes and were insulin resistant. The Saharawi diet was found to mainly include cereals, oils, sugars, vegetables (especially onions, tomatoes, and carrots), tea, and meat. Principal component analysis identified two major dietary patterns, the first one “healthy” and the second one “unhealthy”. Women in the higher tertile of adherence to the unhealthy dietary pattern had a higher homeostatic model assessment for insulin resistance (HOMA) index (b = 2.49; 95% CI: 0.41–4.57; p = 0.02) and circulating insulin (b = 4.52; 95% CI: 0.44–8.60; p = 0.03) than the women in the lowest tertile. Food policies should be oriented to improve the quality of diet of Saharawi diabetic women.

Reproducibility of A Non-Quantitative Food Frequency Questionnaire (62-Item FFQ-6) and PCA-Driven Dietary Pattern Identification in 13-21-Year-Old Females

The aim of this study was to evaluate the test-retest reproducibility of a non-quantitative food frequency questionnaire (acronym: 62-item FFQ-6) and the possibility of identifying dietary patterns (DPs) in 13-21-year-old females. The study involved 97 females within three age groups: 13-15, 16-18, and 19-21 years, including 31, 38, and 28 subjects, respectively. The questionnaire was completed twice with a two-week interval (test and retest). For the total sample, using a principal component analysis (PCA), two similar PCA-driven DPs (DP1 and DP2) were identified separately from test data and retest data, considering two sets of input variables. 60-item-DP1 and 60-item-DP2 were identified after excluding two items-vegetables and fruits in general-due to including single items of various kinds of vegetables and fruits. After an aggregation of some items of the questionnaire, 25-item-DP1 and 25-item-DP2 were identified. The kappa statistic (test vs. retest) in the total sample averaged at 0.52 (0.32-0.72 for food items), while within age groups, it averaged at 0.41, 0.53, and 0.65, respectively. The percentage of subjects classified into the same food frequency category (test vs. retest) in the total sample averaged at 68% (51%-89% for food items), while within age groups, it averaged at 60%, 68%, and 77%, respectively. The Spearman correlations between dietary pattern scores (test vs. retest) in the total sample were: 0.84 (within age groups 0.83, 0.81, and 0.78, respectively) for 60-item-DP1, 0.68 (within age groups 0.24, 0.79, and 0.76, respectively) for 60-item-DP2, 0.76 (within age groups 0.56, 0.82, and 0.89, respectively) for 25-item-DP1, and 0.48 (within age groups 0.40, 0.57, and 0.53, respectively) for 25-item-DP2 (p < 0.05 for all). In conclusion, the test-retest reproducibility of the 62-item FFQ-6 was good or very good for most food items, with a tendency to be higher in older age groups of females under study. Due to the acceptable-to-good reproducibility of dietary pattern identification, the use of a 62-item FFQ-6 to describe the overall diet of young Polish females can be recommended.

A Systematic Review of Principal Component Analysis-Derived Dietary Patterns in Japanese Adults: Are Major Dietary Patterns Reproducible Within a Country?

Principal component analysis (PCA) has been widely used in nutritional epidemiology to derive dietary patterns. However, although PCA-derived dietary patterns are population-dependent, their reproducibility in different populations is largely unexplored. We aimed to investigate whether major dietary patterns are consistently identified among different populations within a country and, if so, how similar these dietary patterns are. We conducted a systematic review of PCA-derived dietary patterns in Japanese adults using PubMed and Web of Science for English articles and Ichushi-Web and CiNii databases for Japanese articles. We assessed the reproducibility of major dietary patterns using congruence coefficients (CCs), with values ≥0.80 considered to represent fair similarity. From 65 articles (80 studies) included in this review, 285 different dietary patterns were identified. Based on the names of these patterns, major dietary patterns were Western (n = 34), Japanese (n = 12), traditional (n = 10), traditional Japanese (n = 9), healthy (n = 18), and prudent (n = 9) patterns. When assessment was limited to high-quality data (i.e., studies based on a sample size ≥200 and use of a validated dietary assessment questionnaire or multiple-day dietary record), the median CC was low for Western (0.44), traditional (0.59), and traditional Japanese (0.31) patterns. Conversely, the median CC was 0.89 for healthy, 0.86 for prudent, and 0.80 for Japanese patterns; and the proportion of pairs with a CC ≥0.80 was 87.3%, 64.3%, and 50.0%, respectively. Characteristics shared among these 3 dietary patterns included higher intakes of mushrooms, seaweeds, vegetables, potatoes, fruits, pulses, and pickles. In conclusion, this systematic review showed that some of the major dietary patterns are relatively reproducible in different populations within a country, whereas others are not. This highlights the importance of careful interpretation of PCA-derived dietary patterns. Our findings in Japan should be confirmed in different countries and globally. This study was registered at https://www.crd.york.ac.uk/prospero/ as CRD42018087669.

Shared and Study-specific Dietary Patterns and Head and Neck Cancer Risk in an International Consortium

BACKGROUND

A few papers have considered reproducibility of a posteriori dietary patterns across populations, as well as pattern associations with head and neck cancer risk when multiple populations are available.

METHODS

We used individual-level pooled data from seven case-control studies (3844 cases; 6824 controls) participating in the International Head and Neck Cancer Epidemiology consortium. We simultaneously derived shared and study-specific a posteriori patterns with a novel approach called multi-study factor analysis applied to 23 nutrients. We derived odds ratios (ORs) and 95% confidence intervals (CIs) for cancers of the oral cavity and pharynx combined, and larynx, from logistic regression models.

RESULTS

We identified three shared patterns that were reproducible across studies (75% variance explained): the Antioxidant vitamins and fiber (OR = 0.57, 95% CI = 0.41, 0.78, highest versus lowest score quintile) and the Fats (OR = 0.80, 95% CI = 0.67, 0.95) patterns were inversely associated with oral and pharyngeal cancer risk. The Animal products and cereals (OR = 1.5, 95% CI = 1.1, 2.1) and the Fats (OR = 1.8, 95% CI = 1.4, 2.3) patterns were positively associated with laryngeal cancer risk, whereas a linear inverse trend in laryngeal cancer risk was evident for the Antioxidant vitamins and fiber pattern. We also identified four additional study-specific patterns, one for each of the four US studies examined. We named them all as Dairy products and breakfast cereals, and two were associated with oral and pharyngeal cancer risk.

CONCLUSION

Multi-study factor analysis provides insight into pattern reproducibility and supports previous evidence on cross-country reproducibility of dietary patterns and on their association with head and neck cancer risk. See video abstract at, http://links.lww.com/EDE/B430.

Compositional analysis of dietary patterns

Instead of looking at individual nutrients or foods, dietary pattern analysis has emerged as a promising approach to examine the relationship between diet and health outcomes. Despite dietary patterns being compositional (i.e. usually a higher intake of some foods implies that less of other foods are being consumed), compositional data analysis has not yet been applied in this setting. We describe three compositional data analysis approaches (compositional principal component analysis, balances and principal balances) that enable the extraction of dietary patterns by using control subjects from the Spanish multicase-control (MCC-Spain) study. In particular, principal balances overcome the limitations of purely data-driven or investigator-driven methods and present dietary patterns as trade-offs between eating more of some foods and less of others.

High adherence to the Western, Prudent, and Mediterranean dietary patterns and risk of gastric adenocarcinoma: MCC-Spain study

BACKGROUND

The influence of dietary habits on the development of gastric adenocarcinoma is not clear. The objective of the present study was to explore the association of three previously identified dietary patterns with gastric adenocarcinoma by sex, age, cancer site, and morphology.

METHODS

MCC-Spain is a multicase-control study that included 295 incident cases of gastric adenocarcinoma and 3040 controls. The association of the Western, Prudent, and Mediterranean dietary patterns-derived in another Spanish case-control study-with gastric adenocarcinoma was assessed using multivariable logistic regression models with random province-specific intercepts and considering a possible interaction with sex and age. Risk according to tumor site (cardia, non-cardia) and morphology (intestinal/diffuse) was evaluated using multinomial regression models.

RESULTS

A high adherence to the Western pattern increased gastric adenocarcinoma risk [odds ratio_{fourth_vs._first_quartile} (95% confidence interval), 2.09 (1.31; 3.33)] even at low levels [odds ratio_{second_vs._first_quartile} (95% confidence interval), 1.63 (1.05; 2.52)]. High adherence to the Mediterranean dietary pattern could prevent gastric adenocarcinoma [odds ratio_{fourth_vs._first_quartile} (95% confidence interval), 0.53 (0.34; 0.82)]. Although no significant heterogeneity of effects was observed, the harmful effect of the Western pattern was stronger among older participants and for non-cardia adenocarcinomas, whereas the protective effect of the Mediterranean pattern was only observed among younger participants and for non-cardia tumors.

CONCLUSION

Decreasing the consumption of fatty and sugary products and of red and processed meat in favor of an increase in the intake of fruits, vegetables, legumes, olive oil, nuts, and fish might prevent gastric adenocarcinoma.

Low adherence to the western and high adherence to the mediterranean dietary patterns could prevent colorectal cancer

PURPOSE

To assess if the associations found between three previously identified dietary patterns with breast, prostate and gastric cancer are also observed for colorectal cancer (CRC).

METHODS

MCC-Spain is a multicase-control study that collected information of 1629 incident cases of CRC and 3509 population-based controls from 11 Spanish provinces. Western, Prudent and Mediterranean data-driven dietary patterns-derived in another Spanish case-control study-were reconstructed in MCC-Spain. Their association with CRC was assessed using mixed multivariable logistic regression models considering a possible interaction with sex. Risk by tumor site (proximal colon, distal colon, and rectum) was evaluated using multinomial regression models.

RESULTS

While no effect of the Prudent pattern on CRC risk was observed, a high adherence to the Western dietary pattern was associated with increased CRC risk for both males [OR_{fourth(Q4) vs. first(Q1)quartile} (95% CI): 1.45 (1.11;1.91)] and females [OR_{Q4 vs. Q1} (95% CI): 1.50 (1.07;2.09)] but seem to be confined to distal colon [OR_{fourth(Q4) vs. first(Q1)quartile} (95% CI): 2.02 (1.44;2.84)] and rectal [OR_{Q4 vs. Q1} (95% CI): 1.46 (1.05;2.01)] tumors. The protective effect of the Mediterranean dietary pattern against CRC was observed for both sexes [males: OR_{Q4 vs. Q1} (95% CI): 0.71 (0.55;0.92); females: OR_{Q4 vs. Q1} (95% CI): 0.56 (0.40;0.77)] and for all cancer sites: proximal colon [OR_{Q4 vs. Q1} (95% CI): 0.70 (0.51;0.97)], distal colon [OR_{Q4 vs. Q1} (95% CI): 0.65 (0.48;0.89)], and rectum (OR_{Q4 vs. Q1} (95% CI): 0.60 (0.45;0.81)].

CONCLUSION

Our results are consistent with most of the associations previously found between these patterns and breast, prostate and gastric cancer risk and indicate that consuming whole fruits, vegetables, legumes, olive oil, nuts, and fish and avoiding red and processed meat, refined grains, sweets, caloric drinks, juices, convenience food, and sauces might reduce CRC risk.

Contribution to the understanding of how principal component analysis-derived dietary patterns emerge from habitual data on food consumption

Background

Principal component analysis (PCA) is a widely used exploratory method in epidemiology to derive dietary patterns from habitual diet. Such dietary patterns seem to originate from intakes on multiple days and eating occasions. Therefore, analyzing food intake of study populations with different levels of food consumption can provide additional insights as to how habitual dietary patterns are formed.

Objective

We analyzed the food intake data of German adults in terms of the relations among food groups from three 24-h dietary recalls (24hDRs) on the habitual, single-day, and main-meal levels, and investigated the contribution of each level to the formation of PCA-derived habitual dietary patterns.

Design

Three 24hDRs were collected in 2010-2012 from 816 adults for an European Prospective Investigation into Cancer and Nutrition (EPIC)-Potsdam subcohort study. We identified PCA-derived habitual dietary patterns and compared cross-sectional food consumption data in terms of correlation (Spearman), consistency (intraclass correlation coefficient), and frequency of consumption across all days and main meals. Contribution to the formation of the dietary patterns was obtained through Spearman correlation of the dietary pattern scores.

Results

Among the meals, breakfast appeared to be the most consistent eating occasion within individuals. Dinner showed the strongest correlations with "Prudent" (Spearman correlation = 0.60), "Western" (Spearman correlation = 0.59), and "Traditional" (Spearman correlation = 0.60) dietary patterns identified on the habitual level, and lunch showed the strongest correlations with the "Cereals and legumes" (Spearman correlation = 0.60) habitual dietary pattern.

Conclusions

Higher meal consistency was related to lower contributions to the formation of PCA-derived habitual dietary patterns. Absolute amounts of food consumption did not strongly conform to the habitual dietary patterns by meals, suggesting that these patterns are formed by complex combinations of variable food consumption across meals. Dinner showed the highest contribution to the formation of habitual dietary patterns. This study provided information about how PCA-derived dietary patterns are formed and how they could be influenced.

Principal components analysis in clinical studies

In multivariate analysis, independent variables are usually correlated to each other which can introduce multicollinearity in the regression models. One approach to solve this problem is to apply principal components analysis (PCA) over these variables. This method uses orthogonal transformation to represent sets of potentially correlated variables with principal components (PC) that are linearly uncorrelated. PCs are ordered so that the first PC has the largest possible variance and only some components are selected to represent the correlated variables. As a result, the dimension of the variable space is reduced. This tutorial illustrates how to perform PCA in R environment, the example is a simulated dataset in which two PCs are responsible for the majority of the variance in the data. Furthermore, the visualization of PCA is highlighted.

Mediterranean Dietary Pattern is Associated with Low Risk of Aggressive Prostate Cancer: MCC-Spain Study

PURPOSE

We explored the association of the previously described Western, prudent and Mediterranean dietary patterns with prostate cancer risk by tumor aggressiveness and extension.

MATERIALS AND METHODS

MCC-Spain (Multicase-Control Study on Common Tumors in Spain) is a population based, multicase-control study that was done in 7 Spanish provinces between September 2008 and December 2013. It collected anthropometric, epidemiological and dietary information on 754 histologically confirmed incident cases of prostate cancer and 1,277 controls 38 to 85 years old. Three previously identified dietary patterns, including Western, prudent and Mediterranean, were reconstructed using MCC-Spain data. The association of each pattern with prostate cancer risk was assessed by logistic regression models with random, province specific intercepts. Risk according to tumor aggressiveness (Gleason score 6 vs greater than 6) and extension (cT1-cT2a vs cT2b-cT4) was evaluated by multinomial regression models.

RESULTS

High adherence to a Mediterranean dietary pattern rich not only in fruits and vegetables but also in fish, legumes and olive oil was specifically associated with a lower risk of Gleason score greater than 6 prostate cancer (quartile 3 vs 1 relative RR 0.66, 95% CI 0.46-0.96 and quartile 4 vs 1 relative RR 0.68, 95% CI 0.46-1.01, p-trend = 0.023) or with higher clinical stage (cT2b-T4 quartile 4 vs 1 relative RR 0.49, 95% CI 0.25-0.96, p-trend = 0.024). This association was not observed with the prudent pattern, which combines vegetables and fruits with low fat dairy products, whole grains and juices. The Western pattern did not show any association with prostate cancer risk.

CONCLUSIONS

Nutritional recommendations for prostate cancer prevention should consider whole dietary patterns instead of individual foods. We found important differences between the Mediterranean dietary pattern, which was associated with a lower risk of aggressive prostate cancer, and Western and prudent dietary patterns, which had no relationship with prostate cancer risk.

Utilizing nutritional genomics to tailor diets for the prevention of cardiovascular disease: a guide for upcoming studies and implementations

INTRODUCTION

Personalized diets based on an individual's genome to optimize the success of dietary intervention and reduce genetic cardiovascular disease (CVD) risk, is one of the challenges most frequently discussed in the scientific community. Areas covered: The authors gathered literature-based evidence on nutritional genomics and CVD phenotypes, our own results and research experience to provide a critical overview of the current situation of using nutritional genomics to tailor diets for CVD prevention and to propose guidelines for future studies and implementations. Expert commentary: Hundreds of studies on gene-diet interactions determining CVD intermediate (plasma lipids, hypertension, etc.) and final phenotypes (stroke, etc.) have furnished top-level scientific evidence for claiming that the genetic effect in cardiovascular risk is not deterministic, but can be modified by diet. However, despite the many results obtained, there are still gaps in practically applying a personalized diet design to specific genotypes. Hence, a better systemization and methodological improvement of new studies is required to obtain top-level evidence that will allow their application in the future precision nutrition/medicine. The authors propose several recommendations for tackling new approaches and applications.