Associations of empirically derived eating patterns with plasma lipid biomarkers: a comparison of factor and cluster analysis methods

Dietary patterns and osteoporosis risk in postmenopausal korean women

Objectives

The prevalence of osteoporosis and related fractures has increased rapidly in Korean women. Proper nutrition intake is associated with the prevention of osteoporosis. We analyzed the association between dietary patterns and the risk of osteoporosis during a 4-year follow-up in postmenopausal Korean women.

Methods

Postmenopausal women (n = 1,725) who participated in the Korean Genome and Epidemiology Study were enrolled. Food intake was assessed using a validated semiquantitative food frequency questionnaire, and a quantitative ultrasound device was used to measure the speed of sound at the radius and tibia.

Results

Three major dietary patterns were identified using factor analysis based on baseline intake data: traditional (high intake of rice, kimchi, and vegetables), dairy (high intake of milk, dairy products, and green tea), and western (high intake of sugar, fat, and bread). Multivariate Cox proportional hazards models were used to estimate relative risk for osteoporosis. An inverse association was detected between the dairy dietary pattern and the osteoporosis incidence [relative risk (RR): 0.63, 95% confidence interval (CI): 0.42–0.93, p-trend=0.055 in radius; RR: 0.56, 95% CI: 0.35–0.90, p-trend=0.048 in tibia]. Individuals in the highest quintile for the traditional dietary pattern (p-trend = 0.009 in tibia) and western dietary pattern (p-trend = 0.043 in radius) demonstrated a higher risk of osteoporosis incidence than those in the lowest quintile.

Conclusion

These results suggested that high consumption of milk, dairy products, and green tea may reduce the risk of osteoporosis in postmenopausal Korean women.

Eating patterns are associated with biomarkers in a selected population of university students and employees

The association between diet and CVD cannot be assigned to a single nutrient, but rather to a set of nutrients and non-nutrients, and eating pattern analyses have become an important tool in investigation of this relationship. Our objective was to investigate eating patterns in relation to nutrient intake and serum concentration of folate, vitamin B12 and TAG in ninety-five healthy adult participants. Dietary information was collected by an FFQ, and eating patterns were obtained by principal components analyses of thirty-three food groups. Three eating patterns were extracted, a sweet eating pattern identified by intakes of cakes, snacks, sugar-sweetened drinks and chocolates; a prudent eating pattern identified by vegetables, fruits and olive oil; and a traditional food pattern identified by red meat, lean fish and cheese. Blood samples were collected in the morning after an overnight fast. Linear regression analyses adjusted for age, BMI and smoking showed a negative association between the sweet eating pattern scores and the serum concentration of folate (β = -2·31 (95 % CI -4·14, -0·45)) and a positive association with serum concentration of TAG (β = 0·35 (95 % CI 0·12, 0·57)). The prudent eating pattern scores were positively associated with the serum concentration of folate (β = 1·69 (95 % CI 0·44, 2·92)). In conclusion, a sweet eating pattern was associated with risk factors for CVD, whereas a prudent eating pattern was associated with protective factors.

The use of cluster analysis to derive dietary patterns: methodological considerations, reproducibility, validity and the effect of energy mis-reporting

Over the last three decades, dietary pattern analysis has come to the forefront of nutritional epidemiology, where the combined effects of total diet on health can be examined. Two analytical approaches are commonly used: a priori and a posteriori. Cluster analysis is a commonly used a posteriori approach, where dietary patterns are derived based on differences in mean dietary intake separating individuals into mutually exclusive, non-overlapping groups. This review examines the literature on dietary patterns derived by cluster analysis in adult population groups, focusing, in particular, on methodological considerations, reproducibility, validity and the effect of energy mis-reporting. There is a wealth of research suggesting that the human diet can be described in terms of a limited number of eating patterns in healthy population groups using cluster analysis, where studies have accounted for differences in sex, age, socio-economic status, geographical area and weight status. Furthermore, patterns have been used to explore relationships with health and chronic diseases and more recently with nutritional biomarkers, suggesting that these patterns are biologically meaningful. Overall, it is apparent that consistent trends emerge when using cluster analysis to derive dietary patterns; however, future studies should focus on the inconsistencies in methodology and the effect of energy mis-reporting.

Dietary patterns and the prevalence of metabolic syndrome in Korean women

BACKGROUND AND AIMS

The role of dietary patterns in metabolic syndrome has not been adequately investigated in Asian women. We aimed to identify dietary patterns and to evaluate the cross-sectional relationship between dietary patterns and the prevalence of metabolic syndrome in Korean women.

METHODS AND RESULTS

In a cross-sectional study of 4984 women aged 30-79 years, dietary patterns were derived from 16 food groups using factor analysis. Metabolic syndrome was defined based on the Adult Treatment Panel III of the National Cholesterol Education Program (ATPIII NCEP) criteria as having three or more risk factors using a modified obesity index. Logistic regression was used to estimate the association between dietary pattern and the prevalence of metabolic syndrome. Three dietary patterns (Western, healthy and traditional) were identified. Higher consumption of the healthy pattern was inversely associated with metabolic syndrome (OR [95% CI] for highest vs. lowest quartile: 0.58 [0.50-0.91]; P for trend = 0.012) and most components of metabolic syndrome. In a stratified analysis by menopausal status, the inverse association of the healthy dietary pattern and metabolic syndrome was statistically significant only among postmenopausal women (OR [95% CI] for highest vs. lowest quartile: 0.60 [0.40-0.86]; P for trend = 0.004). The Western and traditional patterns showed no association with metabolic syndrome, but were related to some individual risk factors for metabolic syndrome.

CONCLUSIONS

These results suggest that the healthy dietary pattern is associated with a reduced risk for metabolic syndrome in Korean women, particularly in postmenopausal women.

Dietary patterns in Irish adolescents: a comparison of cluster and principal component analyses

Objective

Pattern analysis of adolescent diets may provide an important basis for nutritional health promotion. The aims of the present study were to examine and compare dietary patterns in adolescents using cluster analysis and principal component analysis (PCA) and to examine the impact of the format of the dietary variables on the solutions.

Design

Analysis was based on the Irish National Teens Food Survey, in which food intake data were collected using a semi-quantitative 7 d food diary. Thirty-two food groups were created and were expressed as either g/d or percentage contribution to total energy. Dietary patterns were identified using cluster analysis (k-means) and PCA.

Setting

Republic of Ireland, 2005–2006.

Subjects

A representative sample of 441 adolescents aged 13–17 years.

Results

Five clusters based on percentage contribution to total energy were identified, ‘Healthy’, ‘Unhealthy’, ‘Rice/Pasta dishes’, ‘Sandwich’ and ‘Breakfast cereal & Main meal-type foods’. Four principal components based on g/d were identified which explained 28 % of total variance: ‘Healthy foods’, ‘Traditional foods’, ‘Sandwich foods’ and ‘Unhealthy foods’.

Conclusions

A ‘Sandwich’ and an ‘Unhealthy’ pattern are the main dietary patterns in this sample. Patterns derived from either cluster analysis or PCA were comparable, although it appears that cluster analysis also identifies dietary patterns not identified through PCA, such as a ‘Breakfast cereal & Main meal-type foods’ pattern. Consideration of the format of the dietary variable is important as it can directly impact on the patterns obtained for both cluster analysis and PCA.

A comparison of dietary patterns derived by cluster and principal components analysis in a UK cohort of children

BACKGROUND/OBJECTIVES

The objective of this study was to identify dietary patterns in a cohort of 7-year-old children through cluster analysis, compare with patterns derived by principal components analysis (PCA), and investigate associations with sociodemographic variables.

SUBJECTS/METHODS

The main caregivers in the Avon Longitudinal Study of Parents and Children (ALSPAC) recorded dietary intakes of their children (8279 subjects) using a 94-item food frequency questionnaire. Items were then collapsed into 57 food groups. Dietary patterns were identified using k-means cluster analysis and associations with sociodemographic variables examined using multinomial logistic regression. Clusters were compared with patterns previously derived using PCA.

RESULTS

Three distinct clusters were derived: Processed (4177 subjects), associated with higher consumption of processed foods and white bread, Plant-based (2065 subjects), characterized by higher consumption of fruit, vegetables and non-white bread, and Traditional British (2037 subjects), associated with higher consumption of meat, vegetables and full-fat milk. Membership of the Processed cluster was positively associated with girls, younger mothers, snacking and older siblings. Membership of the Plant-based cluster was associated with higher educated mothers and vegetarians. The Traditional British cluster was associated with council housing and younger siblings. The three clusters were similar to the three dietary patterns obtained through PCA; each principal component score being higher on average in the corresponding cluster.

CONCLUSIONS

Both cluster analysis and PCA identified three dietary patterns very similar both in the foods associated with them and sociodemographic characteristics. Both methods are useful for deriving meaningful dietary patterns.

Coronary heart disease prevention: nutrients, foods, and dietary patterns

Diet is a key modifiable risk factor in the prevention and risk reduction of coronary heart disease (CHD). Results from the Seven Countries Study in the early 1970s spurred an interest in the role of single nutrients such as total fat in CHD risk. With accumulating evidence, we have moved away from a focus on total fat to the importance of considering the quality of fat. Recent meta-analyses of intervention studies confirm the beneficial effects of replacing saturated fat with polyunsaturated fatty acids on CHD risk. Scientific evidence for a detrimental role of trans fat intake from industrial sources on CHD risk has led to important policy changes including listing trans fatty acid content on the "Nutrition Facts" panel and banning the use of trans fatty acids in food service establishments in some cities. The effects of such policy changes on changes in CHD incidence are yet to be evaluated. There has been a surging interest in the protective effects of vitamin D in primary prevention. Yet, its associations with secondary events have been mixed and intervention studies are needed to clarify its role in CHD prevention. Epidemiological and clinical trial evidence surrounding the benefit of B vitamins and antioxidants such as carotenoids, vitamin E, and vitamin C, have been contradictory. While pharmacological supplementation of these vitamins in populations with existing CHD has been ineffective and, in some cases, even detrimental, data repeatedly show that consumption of a healthy dietary pattern has considerable cardioprotective effects for primary prevention. Results from these studies and the general ineffectiveness of nutrient-based interventions have shifted interest to the role of foods in CHD risk reduction. The strongest and most consistent protective associations are seen with fruit and vegetables, fish, and whole grains. Epidemiological and clinical trial data also show risk reduction with moderate alcohol consumption. In the past decade, there has been a paradigm shift in nutritional epidemiology to examine associations between dietary patterns and health. Several epidemiological studies show that people following the Mediterranean style diet or the Dietary Approaches to Stop Hypertension (DASH) diet have lower risk of CHD and lower likelihood of developing hypertension. Studies using empirical or data driven dietary patterns have frequently identified two patterns - "Healthy or Prudent" and "Western". In general, the "Healthy", compared to the "Western" pattern has been associated with more favorable biological profiles, slower progression of atherosclerosis, and reduced incidence. Evidence on changes in dietary patterns and changes in CHD risk is still emerging. With the emergence of the concept of personalized nutrition, studies are increasingly considering the role of genetic factors in the modulation of the association between nutrients and CHD. More studies of genetic variation and dietary patterns in relation to CHD are needed.

Dietary patterns are associated with cardiometabolic risk factors in a representative study population of German adults

Studies that investigated complex actual eating behaviours of the general population and their relation to cardiometabolic risk markers are sparse. We aimed to identify dietary patterns within a nationally representative sample of 4025 German adults by factor analysis based on validated dietary history interviews. Furthermore, we evaluated associations of the derived dietary patterns with abnormalities clustered within the metabolic syndrome and related metabolic markers by logistic regression models and ANCOVA. A high adherence to the ‘processed foods’ pattern reflected a high intake of refined grains, processed meat, red meat, high-sugar beverages, eggs, potatoes, beer, sweets and cakes, snacks and butter, whereas a high adherence to the ‘health-conscious’ pattern represented a high intake of vegetables, vegetable oils, legumes, fruits, fish and whole grains. For subjects in the highest compared with those in the lowest quintile of the processed foods pattern, the occurrence of abdominal obesity was 88 (95 % CI 31, 169) % higher, hypertension was 34 (95 % CI − 4, 86) % higher, hypertriacylglycerolaemia was 59 (95 % CI 11, 128 ) % higher and the metabolic syndrome was 64 (95 % CI 10, 143) % higher when adjusted for age, sex, energy intake, socio-economic status, sport activity and smoking. Furthermore, subjects in the highest quintile had statistically significantly higher uric acid concentrations and lower folate concentrations (Pfor trend < 0·05). In contrast, subjects in the highest quintile of the health-conscious pattern had a 30 (95 % CI 10, 46) % lower occurrence of hypertension, higher folate concentrations and lower homocysteine and fibrinogen concentrations (Pfor trend < 0·05). These data strengthen the findings from non-representative studies and emphasise the importance of healthy overall food patterns for preventing metabolic disturbances.

Invited commentary: dietary pattern analysis

The analytic approaches used in nutritional epidemiology for dietary pattern analyses share common characteristics with those of genetic epidemiology. In this issue of the Journal, Gorst-Rasmussen et al. (Am J Epidemiol. 2011;173(10):1097-1104) discuss one such approach. Application of methods used in genetic pattern analyses to nutritional epidemiology could prove valuable but raises important issues that need to be considered because dietary and genetic studies often address different types of questions in analyzing interrelated variables. These different aims require statistical methods that assume different characteristics of the underlying patterns. The authors briefly describe such differences to facilitate interpretation and applications of previous and future pattern studies.

Dietary patterns and their association with obesity and sociodemographic factors in a national sample of Lebanese adults

Objective

To identify and characterize dietary patterns in Lebanon and assess their association with sociodemographic factors, BMI and waist circumference (WC).

Design

A cross-sectional population-based survey. In a face-to-face interview, participants completed a brief sociodemographic and semiquantitative FFQ. In addition, anthropometric measurements were obtained following standard techniques. Dietary patterns were identified by factor analysis. Multivariate linear regression was used to assess determinants of the various patterns and their association with BMI and WC.

Setting

National Nutrition and Non-Communicable Disease Risk Factor Survey (2009), Lebanon.

Subjects

A nationally representative sample of 2048 Lebanese adults aged 20–55 years.

Results

Four dietary patterns were identified: ‘Western’, ‘Traditional Lebanese’, ‘Prudent’ and ‘Fish and alcohol’. Factor scores of the identified patterns increased with age, except for the Western pattern in which a negative association was noted. Women had higher scores for the prudent pattern. Adults with higher levels of education had significantly higher scores for the prudent pattern. The frequency of breakfast consumption was significantly associated with scores of both traditional Lebanese and prudent patterns. Multivariate-adjusted analysis revealed a positive association between scores of the Western pattern and the BMI and WC of study participants.

Conclusions

The findings show the presence of four distinct dietary patterns in the Lebanese population, which were associated with age, sex, education and meal pattern. Only the Western pattern was associated with higher BMI.

Relationship between maternal dietary patterns and hypospadias

Little is known about the role of maternal nutrition in the development of hypospadias, which is the most common urogenital congenital anomaly. This study investigated the relationship between maternal nutrition and the risk of hypospadias, particularly focusing on maternal food patterns. We compared 471 hypospadias cases with 490 controls in the United Kingdom. A questionnaire including information on life style, occupation, usual maternal diet and dietary supplements was administered using telephone interviews. Cases and controls were compared for individual food item intake and food patterns derived by cluster analysis. Multivariable logistic regression analysis adjusted for income, maternal age, low birthweight, smoking and folic acid supplement use was used to assess the relationship between maternal nutrition and hypospadias. Three food patterns were created with the labels 'health conscious', 'mixed' and 'non-health conscious'. 'Non-health conscious' subjects (low frequency of consumption of yoghurt, cheese, eggs, fruit and vegetables, fish, beans and pulses, olive oil and organic food) had a higher risk of hypospadias (odds ratio 1.54; 95% confidence interval 1.06, 2.26) compared with 'health conscious' subjects (high frequency of consumption of fresh fruit and vegetables, dried fruit, fresh or frozen fish, beans, pulses, soya products, olive oil and organic food), after adjustment for potential confounders. Intakes of individual foods were not strongly associated with hypospadias. We could not exclude the possibility of residual confounding, and this needs to be further investigated. We found an association between food pattern and hypospadias, with those with less health conscious food patterns having a higher risk. Further study is needed to confirm this association.

Exploring statistical approaches to diminish subjectivity of cluster analysis to derive dietary patterns: The Tomorrow Project

Dietary patterns derived by cluster analysis are commonly reported with little information describing how decisions are made at each step of the analytical process. Using food frequency questionnaire data obtained in 2001-2007 on Albertan men (n = 6,445) and women (n = 10,299) aged 35-69 years, the authors explored the use of statistical approaches to diminish the subjectivity inherent in cluster analysis. Reproducibility of cluster solutions, defined as agreement between 2 cluster assignments, by 3 clustering methods (Ward's minimum variance, flexible beta, K means) was evaluated. Ratios of between- versus within-cluster variances were examined, and health-related variables across clusters in the final solution were described. K means produced cluster solutions with the highest reproducibility. For men, 4 clusters were chosen on the basis of ratios of between- versus within-cluster variances, but for women, 3 clusters were chosen on the basis of interpretability of cluster labels and descriptive statistics. In comparison with those in other clusters, men and women in the "healthy" clusters by greater proportions reported normal body mass index, smaller waist circumference, and lower energy intakes. The authors' approach appeared helpful when choosing the clustering method for both sexes and the optimal number of clusters for men, but additional analyses are required to understand why it performed differently for women.

Patterns of food acquisition in Brazilian households and associated factors: a population-based survey

OBJECTIVE

To identify food acquisition patterns in Brazil and relate them to the sociodemographic characteristics of the household.

DESIGN

A cross-sectional national Household Budget Survey (HBS). Principal component factor analysis was used to derive food patterns (factors) on the basis of the acquisition of food classified into thirty-two food groups.

SETTING

The source of data originates from the 2002-2003 HBS carried out by the Brazilian Institute of Geography and Statistics between June 2002 and July 2003 using a representative sample of all Brazilian households.

SUBJECT

A total of 48 470 households allocated into 443 strata of households that were geographically and socio-economically homogeneous as a study unit.

RESULTS

We identified two patterns of food acquisition. The first, named 'dual', was characterized by dairy, fruit, fruit juice, vegetables, processed meat, soft drinks, sweets, bread and margarine, and by inverse correlations with Brazilian staple foods. In contrast, the second pattern, named 'traditional', was characterized by rice, beans, manioc, flour, milk and sugar. The 'dual' pattern was associated with higher household educational level, income and the average age of adults on the strata, whereas the 'traditional' presented higher loadings in less-educated households and in the rural setting.

CONCLUSIONS

Dietary patterns described here suggest that policies and programmes to promote healthy eating need to consider that healthy and non-healthy foods may be integrated within [corrected] the same pattern.

Dietary intake patterns are reflected in metabolomic profiles: potential role in dietary assessment studies

BACKGROUND

It has been suggested that metabolomics could play a role in dietary assessment and identification of novel biomarkers of dietary intake.

OBJECTIVE

This study examined the link between habitual dietary patterns and metabolomic profiles.

DESIGN

A total of 160 volunteers participated in a double-blind, randomized, placebo-controlled dietary intervention. We collected biofluids and recorded 3-d food diaries. Food data were reduced to 33 food groups, and a k-means cluster analysis was performed to identify dietary patterns. (1)H Nuclear magnetic resonance (NMR) spectra were acquired for plasma and urine samples, and gas chromatography was used for plasma fatty acid profiling.

RESULTS

Cluster analysis identified 3 distinct dietary patterns on the basis of the energy contribution of different food groups. Dietary clusters were reflected in plasma fatty acid profiles and in metabolomic data. (1)H NMR spectra of urine allowed the identification of metabolites associated with different dietary patterns. Several of the metabolites identified were linked to the intake of specific food groups; in particular, there was a positive association between O-acetylcarnitine and phenylacetylglutamine and red-meat and vegetable intakes, respectively.

CONCLUSIONS

Habitual dietary patterns are shown in metabolomic data. This approach successfully identified potential biomarkers of red-meat and vegetable intakes.

Latent class analysis is useful to classify pregnant women into dietary patterns

Empirical dietary patterns are derived predominantly using principal components, exploratory factor analysis (EFA), or cluster analysis. Interestingly, latent variable models are less used despite their being more flexible to accommodate important characteristics of dietary data and despite dietary patterns being recognized as latent variables. Latent class analysis (LCA) has been shown empirically to be more appropriate to derive dietary patterns than k-means clustering but has not been compared yet to confirmatory factor analysis (CFA). In this article, we derived dietary patterns using EFA, CFA, and LCA on food items, tested how well the classes from LCA were characterized by the factors from CFA, and compared participants' direct classification from LCA on food items compared with 2 a posteriori classifications from factor scores. Methods were illustrated with the Pregnancy, Infection and Nutrition Study, North Carolina, 2000-2005 (n = 1285 women). From EFA and CFA, we found that food items were grouped into 4 factors: Prudent, Prudent with coffee and alcohol, Western, and Southern. From LCA, pregnant women were classified into 3 classes: Prudent, Hard core Western, and Health-conscious Western. There was high agreement between the direct classification from LCA on food items and the classification from the 2-step LCA on factor scores [κ=0.70 (95% CI = 0.66, 0.73)] despite factors explaining only 25% of the total variance. We suggest LCA on food items to study the effect for mutually exclusive classes and CFA to understand which foods are eaten in combination. When interested in both benefits, the 2-step classification using LCA on previously derived factor scores seems promising.

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 in Mexican adults are associated with risk of being overweight or obese

Our objective was to identify and describe the major dietary patterns in the Mexican adult population and their association with being overweight or obese. Dietary intake was evaluated by a FFQ that was completed by 15,890 Mexican adults who participated in the National Health and Nutrition Survey 2006. Dietary patterns were generated by cluster analysis based on the percent contribution to total energy intake from 30 food groups. We identified 3 major dietary patterns: refined foods and sweets (RS), traditional (T), and diverse (D). The T pattern was characterized by low dietary diversity, with maize and maize foods accounting for ~47% of energy intake. This pattern had the lowest contribution of most food groups, with the exception of beans (~4.0%). The RS pattern had the highest contribution of alcohol (9.4%), soft drinks (9.4%), white bread (7.7%), fast food, sweets, and snacks. The D pattern had the lowest contribution of maize (15.5%) and the highest contribution of whole-fat dairy (8.0%), rice and pasta, meat, poultry, eggs, saturated fat, fruits, and vegetables. After adjusting for age, gender, physical activity, socioeconomic status, area, and region, the RS and D dietary patterns were associated with 14 and 17% increased risk of being overweight (P < 0.01) and 20% increased risk of being obese, respectively, compared with the T dietary pattern (P < 0.001). These findings support an association of dietary patterns with being overweight or obese in a nationally representative sample of Mexican adults.

Associations between dietary patterns and flow cytometry-measured biomarkers of inflammation and cellular activation in the Atherosclerosis Risk in Communities (ARIC) Carotid Artery MRI Study

BACKGROUND

Specific foods and overall dietary patterns are associated with soluble biomarkers of systemic inflammation and endothelial activation. However, no large epidemiological studies have evaluated relationships between such dietary factors and cell-specific markers of activation and inflammation as measured by flow cytometry.

METHODS

Cell aggregates and multiple platelet and leukocyte markers were quantified by flow cytometry in fresh whole blood from 1101 white adults participating in the Carotid Artery MRI Study, a subset of the larger Atherosclerosis Risk in Communities (ARIC) Study. Two dietary patterns ("Healthy" and "Western") were empirically derived via principal components analysis using data collected by food frequency questionnaire. Cross-sectional associations between dietary patterns and flow cytometry-measured biomarkers were evaluated, adjusting for demographics and lifestyle factors, including medications use.

RESULTS

After multivariable adjustment, monocyte lipopolysaccharide receptor (CD14), monocyte toll-like receptor-2, and platelet glycoprotein IIb (CD41) showed inverse associations with the Healthy dietary pattern (p=0.01, 0.04, and 0.01, respectively). In contrast, the Western dietary pattern was positively associated with CD41 and platelet-granulocyte aggregates (p=0.01 and 0.04, respectively). Independent of other dietary factors, alcohol consumption was inversely associated with levels of pan-leukocyte marker (CD45), P-selectin (CD62P) on PLA1 and on PLA2 platelets, and platelet-monocyte, platelet-granulocyte, and platelet-lymphocyte aggregates.

CONCLUSION

Dietary patterns and alcohol intake were each cross-sectionally associated with select markers of cellular activation and inflammation measured by flow cytometry. These data are consistent with the hypothesis that holistic measures of dietary intake are associated with inflammation.

Dietary patterns: biomarkers and chronic disease riskThis paper is one of a selection of papers published in the CSCN–CSNS 2009 Conference, entitled Are dietary patterns the best way to make nutrition recommendations for chronic disease prevention?

With increasing appreciation of the complexity of diets consumed by free-living individuals, there is interest in the assessment of the overall diet or dietary patterns in which multiple related dietary characteristics are considered as a single exposure. The 2 most frequently used methods to derive dietary patterns use (i) scores or indexes based on prevailing hypotheses about the role of dietary factors in disease prevention; and (ii) factors and clusters from exploration of available dietary data. A third method, a hybrid of the hypothesis-driven and data-driven methods, attempts to predict food combinations related to nutrients or biomarkers with hypothesized associations with particular health outcomes. Dietary patterns derived from the first 2 approaches have been examined in relation to nutritional and disease biomarkers and various health outcomes, and generally show the desirable dietary pattern to be consistent with prevalent beliefs about what constitutes a healthful diet. Results from observational studies suggest that the healthful dietary patterns were associated with significant but modest risk reduction (15%–30%) for all-cause mortality and coronary heart disease. Findings for various cancers have been inconsistent. The available randomized controlled intervention trials with a long-term follow-up to examine dietary patterns in relation to health outcome have generally produced null findings. Novel findings with the potential to change existing beliefs about diet and health relationships are yet to emerge from the dietary patterns research. The field requires innovation in methods to derive dietary patterns, validation of prevalent methods, and assessment of the effect of dietary measurement error on dietary patterns.

Comparing 3 dietary pattern methods--cluster analysis, factor analysis, and index analysis--With colorectal cancer risk: The NIH-AARP Diet and Health Study

The authors compared dietary pattern methods-cluster analysis, factor analysis, and index analysis-with colorectal cancer risk in the National Institutes of Health (NIH)-AARP Diet and Health Study (n = 492,306). Data from a 124-item food frequency questionnaire (1995-1996) were used to identify 4 clusters for men (3 clusters for women), 3 factors, and 4 indexes. Comparisons were made with adjusted relative risks and 95% confidence intervals, distributions of individuals in clusters by quintile of factor and index scores, and health behavior characteristics. During 5 years of follow-up through 2000, 3,110 colorectal cancer cases were ascertained. In men, the vegetables and fruits cluster, the fruits and vegetables factor, the fat-reduced/diet foods factor, and all indexes were associated with reduced risk; the meat and potatoes factor was associated with increased risk. In women, reduced risk was found with the Healthy Eating Index-2005 and increased risk with the meat and potatoes factor. For men, beneficial health characteristics were seen with all fruit/vegetable patterns, diet foods patterns, and indexes, while poorer health characteristics were found with meat patterns. For women, findings were similar except that poorer health characteristics were seen with diet foods patterns. Similarities were found across methods, suggesting basic qualities of healthy diets. Nonetheless, findings vary because each method answers a different question.

Role of dietary patterns for dioxin and PCB exposure

Dietary patterns were related to intake and blood concentrations of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/PCDFs), dioxin-like polychlorinated biphenyls (dl-PCBs) and selected non-dioxin-like-PCBs (ndl-PCBs). Intake calculations were based on an extensive food frequency questionnaire and a congener-specific database on concentrations in Norwegian foods. The study (2003) applied a two-step inclusion strategy recruiting representative (n=73) and high consumers (n=111) of seafood and game. Estimated median intakes of sum PCDD/PCDFs and dl-PCBs of the representative and high consumers were 0.78 and 1.25 pg toxic equivalents (TEQ)/kg bw/day, respectively. Estimated median intakes of ndl-PCBs (sum chlorinated biphenyl (CB)-28, 52, 101, 138, 153, 180) were 4.26 and 6.40 ng/kg bw/day. The median blood concentrations of PCDD/PCDFs/dl-PCBs were 28.7 and 35.1 pg TEQ/g lipid, and ndl-PCBs (sum of CB-101, 138, 153 and 180) 252 and 299 ng/g lipid. The Spearman correlations between dietary intake and serum concentration were r=0.34 (p=0.017) for dl-compounds and r=0.37 (p<0.001) for ndl-PCBs. Oily fish was the major source of dl-compounds and ndl-PCBs in high and representative consumers. Four dietary patterns were identified by principal component analysis. Two were related to high intakes, one dominated by oily fish ((Omega-3)), the other by fish liver and seagull eggs ("northern coastal"). Only the latter was closely associated with high blood concentrations of dioxins and PCBs.

Do dietary patterns in older men influence change in homocysteine through folate fortification? The Normative Aging Study

Objective

We aimed to describe the difference in B-vitamin intake and in plasma B-vitamin and homocysteine concentrations before and after folic acid fortification, in relation to dietary patterns.

Design

The Normative Aging Study (NAS) is a longitudinal study on ageing. Between 1961 and 1970, 2280 male volunteers aged 21–80 years (mean 42 years) were recruited. Dietary intake data have been collected since 1987 and assessment of plasma B vitamins and homocysteine was added in 1993.

Setting

Boston, Massachusetts, USA.

Subjects

In the present study, 354 men who had completed at least one FFQ and one measurement of homocysteine, both before and after the fortification period, were included.

Results

Three dietary patterns were identified by cluster analysis: (i) a prudent pattern, with relatively high intakes of fruit, vegetables, low-fat milk and breakfast cereals; (ii) an unhealthy pattern, with high intakes of baked products, sweets and added fats; and (iii) a low fruit and vegetable but relatively high alcohol intake pattern. Dietary intake and plasma concentrations of folate increased significantly (P < 0·05) among all dietary patterns after the fortification period. Homocysteine tended to decrease in supplement non-users and in subjects in the high alcohol, low fruit and vegetable dietary pattern (both P = 0·08).

Conclusions

After fortification with folic acid, folate intake and plasma folate concentration increased significantly in all dietary patterns. There was a trend towards greatest homocysteine lowering in the high alcohol, low fruit and vegetable group.

Adherence to the Mediterranean diet and risk of metabolic syndrome and its components

BACKGROUND AND AIMS

The role of diet in the aetiology of metabolic syndrome (MetS) is not well understood. The aim of the present study was to evaluate the relationship between adherence to the Mediterranean diet (MedDiet) and MetS.

METHODS AND RESULTS

A cross-sectional study was conducted with 808 high cardiovascular risk participants of the Reus PREDIMED Centre. MetS was defined by the updated National Cholesterol and Education Program Adult Treatment Panel III criteria. An inverse association between quartiles of adherence to the MedDiet (14-point score) and the prevalence of MetS (P for trend<0.001) was observed. After adjusting for age, sex, total energy intake, smoking status and physical activity, participants with the highest score of adherence to the MedDiet (>/=9 points) had the lowest odds ratio of having MetS (OR [95% CI] of 0.44 [0.27-0.70]) compared to those in the lowest quartile. Participants with the highest MedDiet adherence had 47 and 54% lower odds of having low HDL-c and hypertriglyceridemia MetS criteria, respectively, than those in the lowest quartile. Some components of the MedDiet, such as olive oil, legumes and red wine were associated with lower prevalence of MetS.

CONCLUSION

Higher adherence to a Mediterranean diet is associated with a significantly lower odds ratio of having MetS in a population with a high risk of cardiovascular disease.

Mediterranean diet and metabolic syndrome: the evidence

Background

The Mediterranean diet has long been related to a lower cardiovascular disease risk; however, more recent evidences also indicate that it has a favourable effect on adiposity and type 2 diabetes.

Design

Review of the available literature in relation to Mediterranean diet and metabolic syndrome.

Results

Several components of Mediterranean diet patterns have been inversely related with body mass index. They are considered to be modulators of insulin resistance, can exert beneficial effects on blood pressure, improve atherogenic dyslipidemia or attenuate the inflammatory burden associated with metabolic syndrome. Furthermore, a lower prevalence of metabolic syndrome has been associated with dietary patterns rich in fruits and vegetables, nuts, olive oil, legumes and fish, moderate in alcohol and low in red meat, processed meat, refined carbohydrates and whole-fat dairy products.

Conclusions

There is much evidence suggesting that the Mediterranean diet could serve as an anti-inflammatory dietary pattern, which could help to fight diseases related to chronic inflammation, including metabolic syndrome.

Cross-sectional association of dietary patterns with insulin-resistant phenotypes among adults without diabetes in the Framingham Offspring Study

Cluster analysis is a valuable tool for exploring the health consequences of consuming different dietary patterns. We used this approach to examine the cross-sectional relationship between dietary patterns and insulin-resistant phenotypes, including waist circumference, BMI, fasting insulin, 2 h post-challenge insulin, insulin sensitivity index (ISI0,120), HDL-cholesterol, TAG and blood pressure, using data from the fifth examination cycle of the Framingham Offspring Study. Among 2875 participants without diabetes, we identified four dietary patterns based on the predominant sources of energy: 'Fruits, Reduced Fat Dairy and Whole Grains', 'Refined Grains and Sweets', 'Beer' and 'Soda'. After adjusting for multiple comparisons and potential confounders, compared with the 'Fruits, Reduced Fat Dairy and Whole Grains' pattern, the 'Refined Grains and Sweets' pattern had significantly higher mean waist circumference (92.4 v. 90.5 cm; P = 0.008) and BMI (27.3 v. 26.6 kg/m2; P = 0.02); the 'Soda' pattern had significantly higher mean fasting insulin concentration (31.3 v. 28.0 microU/ml; P < or = 0.001); the 'Beer' pattern had significantly higher mean HDL-cholesterol concentration (1.46 v. 1.31 mmol/l; P < 0.001). No associations were observed between dietary patterns and ISI0,120, TAG, and systolic or diastolic blood pressure. Our findings suggest that consumption of a diet rich in fruits, vegetables, whole grains and reduced-fat dairy protects against insulin-resistant phenotypes and displacing these healthy choices with refined grains, high-fat dairy, sweet baked foods, candy and sugar-sweetened soda may promote insulin-resistant phenotypes.

Dietary patterns and quality in West-African immigrants in Madrid

BACKGROUND

Eating patterns of immigrants deserve to be better documented because they may reflect the extent of acculturation and associated health risks. The study assessed dietary patterns and quality in Bubi immigrants (from Equatorial Guinea) using cluster analysis and comparing different diet quality indexes.

METHODS

A random sample of 83 Bubi men and 130 women living in Madrid were studied. A 99-item food frequency questionnaire was administered, body weights and heights were self-reported and socio-demographic and health information was collected during interviews. Usual intakes were collapsed into 19 food groups. Cluster analysis of standardized food intakes per 1000 kcalories was performed. Dietary quality was appraised using the Alternative Mediterranean Diet Score, the Alternative Healthy Eating Index and scores of micronutrient adequacy and prevention based on WHO/FAO recommendations.

RESULTS

Two dietary patterns were identified. The 'Healthier' pattern, so confirmed by two dietary quality indexes, featured a higher consumption of fish, fruits, vegetables, legumes, dairy products and bread while the 'Western' pattern included more processed meat, animal fat, and sweetened foods and drinks. One third of the subjects were in the 'Healthier' food cluster, with the same proportion of men and women. Age >or= 30 and residence in Madrid >or= 11 years were independently associated with the healthier diet. Consumption of traditional foods was unrelated to dietary pattern, however. Overall, Bubi diets were somewhat protective because of high intakes of fruits and vegetables and monounsaturated fat (olive oil), but not with respect to sugar, cholesterol, omega-3 fatty acids and fibre. Less than two thirds of subjects had adequate intakes of iron, calcium and folate in both dietary phenotypes. Body mass index, physical exercise, and self-reported health and cardiovascular disease condition showed no significant association with the dietary pattern.

CONCLUSION

Cluster analysis combined with dietary quality assessment facilitates the interpretation of dietary patterns, but choosing the appropriate quality indexes is a problem. A small number of such indexes should be standardized and validated for international use. In the group studied, younger subjects and more recent immigrants were more likely to have a 'Western' pattern and should be a priority target for nutrition communication.

Obesogenic clusters: multidimensional adolescent obesity-related behaviors in the U.S

BACKGROUND

Diet, physical activity, and psychosocial factors are independent and potentially interactive obesity determinants, but few studies have explored complex behavior patterns.

PURPOSE

The purpose of this study is to examine obesity-related behavior patterning and identify high-risk adolescent groups.

METHODS

Cluster analysis identified groups with shared behavior patterns in the National Longitudinal Study of Adolescent Health (1995 and 1996, ages 11-21; N = 9,251). Descriptive and multivariate regression analyses compared sociodemographics and prevalent and incident obesity across clusters.

RESULTS

Seven and six clusters in males and females, respectively, represented behavior patterns such as School Clubs & Sports, Sedentary Behaviors, Dieters, and Junk Food & Low Activity. Sociodemographics varied across clusters. Compared to School Clubs & Sports clusters, adjusted odds of prevalent and incident obesity were higher for most clusters in females but not males.

CONCLUSIONS

Cluster analysis identified several obesogenic behavior patterns, highlighting areas for future research and potential avenues for interventions that target broad lifestyle factors.

Dietary patterns and health and nutrition outcomes in men living with HIV infection

BACKGROUND

Nutritional status is an important determinant of HIV outcomes.

OBJECTIVE

We assessed the association between dietary patterns identified by cluster analysis and change in body mass index (BMI; in kg/m(2)), CD4 count, and viral load (VL).

DESIGN

HIV-positive adult male subjects (n = 348) with a BMI >or= 20.5 were evaluated by biochemical, body composition, and dietary data. Cluster analysis was performed on 41 designated food groups derived from 3-d food records. Dietary clusters were compared for sociodemographic, nutrient intake, and clinical outcomes. Multivariate linear regression assessed associations between dietary clusters and change in BMI, CD4 count, and VL.

RESULTS

We observed 3 dietary patterns: juice and soda; fast food and fruit drinks; and fruit, vegetable, and low-fat dairy. Subjects in the fast food and fruit drinks pattern had the lowest fiber intake, highest VL, and lowest CD4 count and had a lower income than did subjects in the other 2 clusters. Subjects in the fruit, vegetable, and low-fat dairy diet pattern had higher intakes of protein, fiber, and micronutrients and the highest BMI and CD4 count. Subjects in the juice and soda pattern had higher energy intakes and lowest BMI. On average, the fast food and fruit drinks cluster and fruit, vegetable, and low-fat dairy cluster gained 0.33 (P = 0.06) and 0.42 (P = 0.02), respectively, more in BMI than the juice and soda cluster across the study interval in a multivariate model.

CONCLUSIONS

In a cohort of HIV-positive men, we identified 3 distinct dietary patterns; each pattern was associated with specific nutrition, demographic, and HIV-related variables.

Food patterns and cardiovascular disease risk factors: the Swedish INTERGENE research program

BACKGROUND

Analyzing the impact of the intake of many foods simultaneously provides additional knowledge about analyses of nutrients and might make it easier to implement recommendations for the public.

OBJECTIVE

The objective was to examine food patterns in a Swedish population and determine how they are related to metabolic risk factors for cardiovascular disease.

DESIGN

The study is based on data from the INTERGENE population study of women and men aged 25-74 y in western Sweden. Dietary patterns were identified with cluster analysis of 93 food frequencies reported by 3452 participants. Associations with features of the metabolic syndrome, including blood lipids, blood pressure, and anthropometric measures, were analyzed.

RESULTS

Five distinct food patterns were identified, of which one was interpreted as a "healthy" reference pattern. This healthy cluster was distinguished by more frequent consumption of high-fiber and low-fat foods and lower consumption of products rich in fat and sugar. The 4 other clusters differed significantly from the reference cluster with respect to prevalence of cardiovascular disease risk factors and the metabolic syndrome. For example, body mass index and waist-to-hip ratio were significantly higher in a cluster characterized by high consumption of energy-dense drinks and white bread and low consumption of fruit and vegetables (P < 0.0001 and P = 0.004, respectively).

CONCLUSIONS

It is possible to distinguish food patterns that are related to obesity and obesity-related cardiovascular disease risk factors in contrast with a more healthy pattern conforming with current dietary guidelines. Thus, the results indicate no reason for questioning the current recommendations.

Food intake patterns may explain the high prevalence of cardiovascular risk factors among Iranian women

Some cardiovascular risk factors are more prevalent in Middle Eastern countries than in other parts of the world. Lifestyle-related factors, including diet, might account for this discrepancy. We aimed to identify the association between food intake patterns and cardiovascular risk factors among Iranian adult women. We studied 486 apparently healthy Iranian women aged 40-60 y. We used a Willett-format FFQ for collecting dietary data. Fasting plasma glucose (FPG) concentrations, lipid profiles, and blood pressure were measured. Diabetes was defined as FPG > or = 6.93 mmol/L; dyslipidemia was based on Adult Treatment Panel III and hypertension on Joint National Committee VI recommendations. The presence of at least 1 risk factor and at least 2 risk factors of the 3 major risk factors for cardiovascular disease (hypertension, dyslipidemia, and diabetes) was also evaluated. We identified 3 major eating patterns (healthy, Western, and Iranian). After controlling for potential confounders, subjects in the top quintile of the healthy dietary pattern were less likely to have dyslipidemia [odds ratio (OR), 0.36; 95% CI, 0.19-0.53], hypertension (OR, 0.33; 95% CI, 0.17-0.60), at least 1 (OR, 0.30; 95% CI, 0.18-0.58), and at least 2 risk factors (OR, 0.39; 95% CI, 0.20-0.77) compared with the lowest quintile. In contrast, those with greater adherence to the Western dietary pattern had greater odds for cardiovascular risk factors (OR, 2.59-3.11; P < 0.05). The Iranian dietary pattern was significantly associated with dyslipidemia (OR, 1.73; 95% CI, 1.02-2.99) and at least 1 risk factor (OR, 1.89; 95% CI, 1.05-3.20). The major dietary patterns and diabetes were not associated. Eating patterns of this Middle Eastern population might explain the higher prevalence of some cardiovascular risk factors in this region. However, our findings need to be confirmed in other Middle Eastern countries.

A priori-defined dietary patterns and markers of cardiovascular disease risk in the Multi-Ethnic Study of Atherosclerosis (MESA)

BACKGROUND

The level of detail regarding the dietary intake necessary to characterize associations between diet and cardiovascular disease (CVD) risk is uncertain.

OBJECTIVE

We evaluated a unique a priori-defined dietary pattern in relation to several traditional and novel CVD risk factors.

DESIGN

At the baseline examination, diet (by food-frequency questionnaire), markers of inflammation, subclinical atherosclerosis, renal disease, vascular compliance, and other traditional risk factors were measured in 5089 men and women aged 45-84 y without clinical CVD or diabetes from the Multi-Ethnic Study of Atherosclerosis (MESA). We defined a Comprehensive Healthy Dietary Pattern by summing weighted categorical ranks of 36 narrowly defined food groups (21 rated favorably with categorical ranks x +1.0 and 15 rated unfavorably with categorical ranks x -1.0). We also defined a Simplified Healthy Dietary Pattern composed of 3 favorable (whole grains, fruit, and seeds and nuts) and 3 unfavorable (added fats and oils, processed meats, and fried potatoes) food groups using similar scoring techniques and determined the difference between the comprehensive and simplified scores.

RESULTS

The Comprehensive Healthy Dietary Pattern was associated with lower urinary albumin:creatinine ratios, common carotid intima-media thickness, measures of adiposity, and inflammatory marker, triacylglycerol, and insulin concentrations. The magnitudes of most of the associations were similar between the 2 dietary patterns, but some differences were observed between scores. Dietary patterns were not associated with blood pressure, coronary artery calcification, internal carotid intima-media thickness, or the ankle brachial index.

CONCLUSIONS

Many food groups contribute to the characterization of relations with a variety of CVD risk markers, although only 6 food groups contribute much of the information in MESA.

Comparison of cluster and principal component analysis techniques to derive dietary patterns in Irish adults

The aims of the present study were to examine and compare dietary patterns in adults using cluster and factor analyses and to examine the format of the dietary variables on the pattern solutions (i.e. expressed as grams/day (g/d) of each food group or as the percentage contribution to total energy intake). Food intake data were derived from the North/South Ireland Food Consumption Survey 1997-9, which was a randomised cross-sectional study of 7 d recorded food and nutrient intakes of a representative sample of 1379 Irish adults aged 18-64 years. Cluster analysis was performed using the k-means algorithm and principal component analysis (PCA) was used to extract dietary factors. Food data were reduced to thirty-three food groups. For cluster analysis, the most suitable format of the food-group variable was found to be the percentage contribution to energy intake, which produced six clusters: 'Traditional Irish'; 'Continental'; 'Unhealthy foods'; 'Light-meal foods & low-fat milk'; 'Healthy foods'; 'Wholemeal bread & desserts'. For PCA, food groups in the format of g/d were found to be the most suitable format, and this revealed four dietary patterns: 'Unhealthy foods & high alcohol'; 'Traditional Irish'; 'Healthy foods'; 'Sweet convenience foods & low alcohol'. In summary, cluster and PCA identified similar dietary patterns when presented with the same dataset. However, the two dietary pattern methods required a different format of the food-group variable, and the most appropriate format of the input variable should be considered in future studies.

Identification and reproducibility of dietary patterns in a Danish cohort: the Inter99 study

We aimed to identify dietary patterns in a Danish adult population and assess the reproducibility of the dietary patterns identified. Baseline data of 3372 women and 3191 men (30–60 years old) from the population-based survey Inter99 was used. Food intake, assessed by a FFQ, was aggregated into thirty-four separate food groups. Dietary patterns were identified by principal component analysis. Confirmatory factor analysis and Bland Altman plots were used to assess the reproducibility of the dietary patterns identified. The Bland Altman plots were used as an alternative and new method. Two factors were retained for both women and men, which accounted for 15·1–17·4 % of the total variation. The ‘Traditional’ pattern was characterised by high loadings ( ≥ 0·40) on paté or high-fat meat for sandwiches, mayonnaise salads, red meat, potatoes, butter and lard, low-fat fish, low-fat meat for sandwiches, and sauces. The ‘Modern’ pattern was characterised by high loadings on vegetables, fruit, mixed vegetable dishes, vegetable oil and vinegar dressing, poultry, and pasta, rice and wheat kernels. Small differences were observed between patterns identified for women and men. The root mean square error approximation from the confirmatory factor analysis was 0·08. The variation observed from the Bland Altman plots of factors from explorativev. confirmative analyses and explorative analyses from two sub-samples was between 18·8 and 47·7 %. Pearson's correlation was >0·89 (P < 0·0001). The reproducibility was better for women than for men. We conclude that the ‘Traditional’ and ‘Modern’ dietary patterns identified were reproducible.

Under-reporting of energy intake is more prevalent in a healthy dietary pattern cluster

The aim of the present study was to determine whether under-reporting rates vary between dietary pattern clusters. Subjects were sixty-five Brazilian women. During 3 weeks, anthropometric data were collected, total energy expenditure (TEE) was determined by the doubly labelled water method and diet was measured. Energy intake (EI) and the daily frequency of consumption per 1000 kJ of twenty-two food groups were obtained from a FFQ. These frequencies were entered into a cluster analysis procedure in order to obtain dietary patterns. Under-reporters were defined as those who did not lose more than 1 kg of body weight during the study and presented EI:TEE less than 0.82. Three dietary pattern clusters were identified and named according to their most recurrent food groups: sweet foods (SW), starchy foods (ST) and healthy (H). Subjects from the healthy cluster had the lowest mean EI:TEE (SW = 0.86, ST = 0.71 and H = 0.58; P = 0.003) and EI - TEE (SW = - 0.49 MJ, ST = - 3.20 MJ and H = - 5.08 MJ; P = 0.008). The proportion of under-reporters was 45.2 (95 % CI 35.5, 55.0) % in the SW cluster; 58.3 (95 % CI 48.6, 68.0) % in the ST cluster and 70.0 (95 % CI 61.0, 79) % in the H cluster (P = 0.34). Thus, in Brazilian women, under-reporting of EI is not uniformly distributed among dietary pattern clusters and tends to be more severe among subjects from the healthy cluster. This cluster is more consistent with both dietary guidelines and with what lay individuals usually consider 'healthy eating'.

Can dietary patterns help us detect diet–disease associations?

The role of diet in promoting health and preventing disease is difficult to elucidate due to its complex network of foods and nutrients. Besides total energy intake, dietary composition is probably the most important discriminator within and between populations. Dietary composition is reflected in dietary patterns, which have recently gained popularity. The present paper reviews the most commonly applied methods to identify dietary patterns, data-driven methods such as factor and cluster analysis, investigator-driven methods such as indices and score, and methods combining the two, namely reduced rank regression. We describe the techniques and their application, discuss strengths and limitations, and discuss the usefulness of dietary pattern analyses.

A diet high in fruits and low in meats reduces the risk of colorectal adenomas

Recent evidence suggests overall dietary patterns, rather than specific dietary components, may be a better predictor of colorectal adenomas or cancers. Using cluster analysis, we aimed to assess the association between dietary patterns and colorectal adenomas and whether adjusting for total energy consumption prior to creating clusters affects this relation. Data from a case-control study of 725 individuals undergoing a colonoscopy were utilized. Cases (n = 203) had > or =1 adenoma on colonoscopy, and controls (n = 522) were those who had no adenomas. Dietary data were obtained from an FFQ. Daily intake for 18 different food groups was calculated. The values were transformed into Z-scores. Participants were first clustered without energy adjustment, then again based on their consumption per 1000 kcal (4187 kJ). There was no association between dietary patterns and colorectal adenomas without energy adjustment prior to creating dietary clusters, as clusters formed as a by-product of energy consumption. After adjusting for energy consumption, 3 distinct clusters emerged: 1) high fruit-low meat cluster; 2) high vegetable-moderate meat cluster; and 3) high meat cluster. After adjusting for potential confounders, the high vegetable-moderate meat cluster (odds ratio [OR] 2.17: [95% CI] 1.20-3.90) and high meat cluster (OR 1.70: [95% CI] 1.04-2.80) were at significantly increased odds of having had an adenoma compared with the high fruit-low meat cluster. A high-fruit, low-meat diet appears to be protective against colorectal adenomas compared with a dietary pattern of increased vegetable and meat consumption.

Dietary patterns, insulin resistance, and prevalence of the metabolic syndrome in women

BACKGROUND

Although individual foods and nutrients have been associated with the metabolic syndrome, whether dietary patterns identified by factor analysis are also associated with this syndrome is not known.

OBJECTIVE

We aimed to evaluate the association of major dietary patterns characterized by factor analysis with insulin resistance and the metabolic syndrome among women.

DESIGN

Usual dietary intakes were assessed in a cross-sectional study of 486 Tehrani female teachers aged 40-60 y. Anthropometric and blood pressure measurements were performed, and fasting blood samples were taken for biomarker assessment. The metabolic syndrome was defined according to Adult Treatment Panel III guidelines, and insulin resistance was defined as the highest quartile of the homeostasis model assessment scores.

RESULTS

We identified 3 major dietary patterns by factor analysis: the healthy dietary pattern, the Western dietary pattern, and the traditional dietary pattern. After control for potential confounders, subjects in the highest quintile of healthy dietary pattern scores had a lower odds ratio for the metabolic syndrome (odds ratio: 0.61; 95% CI: 0.30, 0.79; P for trend < 0.01) and insulin resistance (0.51; 0.24, 0.88; P for trend < 0.01) than did those in the lowest quintile. Compared with those in the lowest quintile, women in the highest quintile of Western dietary pattern scores had greater odds for the metabolic syndrome (1.68; 1.10, 1.95; P for trend < 0.01) and insulin resistance (1.26; 1.00, 1.78; P for trend < 0.01). Higher consumption of traditional dietary pattern was significantly associated only with abnormal glucose homeostasis (1.19; 1.04, 1.59; P < 0.05).

CONCLUSION

Significant associations exist between dietary patterns identified by factor analysis, the metabolic syndrome, and insulin resistance.

Mediterranean diet and metabolic syndrome: a cross-sectional study in the Canary Islands

Objective

Assessment of relation between metabolic syndrome (MS) and Mediterranean diet (MD) adherence.

Design

Cross-sectional study. ATP III definition of MS was used. Adherence to MD was assessed with a Food Frequency Questionnaire. Intakes of cereal, fruit, legumes, vegetables, fish, nuts, monounsaturated to saturated ratio, alcohol from red wine, whole-fat dairy products and red meat were considered.

Setting

Representative sample of population from the Canary Islands (Spain) participating in the Canarian Nutrition Survey (ENCA).

Subjects

578 adults>18 years.

Results

Of the subjects, 24.4% presented MS. Once adjusted, MD adherence was not related to MS prevalence, but subjects in the third tertile of adherence presented 70% lower prevalence of the blood pressure criteria and 2.5 times more prevalence of the glycaemia criteria with respect to the first tertile. Red meat intake was associated with higher prevalence of blood pressure criteria. Moderate alcohol intake from red wine was associated with lower prevalence of these criteria in women and lower prevalence of HDL cholesterol criteria in men. Fruit intake showed a protective effect on triglyceride criteria, whereas vegetable intake was associated with higher prevalence of this criterion. Cereals' intake showed a protective effect over insulin resistance measured by high insulinaemia level. Fruit intake showed a significative protective effect over high Homeostasis Model Assessment index. Whole-fat dairy products showed a significant protective effect on the glycaemia criteria. High monounsaturated to saturated fatty acid intake showed a protective effect on insulin resistance.

Conclusions

Some components of the MD showed a protective effect on the MS and its components.

Nutritional antioxidants and age-related cataract and maculopathy

Loss of vision is the second greatest, next to death, fear among the elderly. Age-related cataract (ARC) and maculopathy (ARM) are two major causes of blindness worldwide. There are several important reasons to study relationships between risk for ARC/ARM and nutrition: (1) because it is likely that the same nutritional practices that are associated with prolonged eye function will also be associated with delayed age-related compromises to other organs, and perhaps, aging in general, (2) surgical resources are insufficient to provide economic and safe surgeries for cataract and do not provide a cure for ARM, and (3) there will be considerable financial savings and improvements in quality of life if health rather than old age is extended, particularly given the rapidly growing elderly segment of our population. It is clear that oxidative stress is associated with compromises to the lens and retina. Recent literature indicates that antioxidants may ameliorate the risk for ARC and ARM. Given the association between oxidative damage and age-related eye debilities, it is not surprising that over 70 studies have attempted to relate antioxidant intake to risk for ARC and ARM. This article will review epidemiological literature about ARC and ARM with emphasis on roles for vitamins C and E and carotenoids. Since glycation and glycoxidation are major molecular insults which involve an oxidative stress component, we also review new literature that relates dietary carbohydrate intake to risk for ARC and ARM. To evaluate dietary effects as a whole, several studies have tried to relate dietary patterns to risk for ARC. We will also give some attention to this emerging research. While data from the observational studies generally support a protective role for antioxidants in foods or supplements, results from intervention trials are less encouraging with respect to limiting risk for ARC/ARM prevalence or progress through antioxidant supplementations, or maintaining higher levels of antioxidants either in diet or blood. Without more information it is difficult to parse these results. It would be worthwhile to determine why the various types of studies are not yielding similar results. However, there are many common insults and mechanistic compromises that are associated with aging, and proper nutrition early in life may address some of these compromises and provide for extended youthful function later in life. Indeed, proper nutrition, possibly including use of antioxidant supplements for the nutritionally impoverished, along with healthy life styles may provide the least costly and most practical means to delay ARC and ARM. Further studies should be devoted to identifying the most effective strategy to prevent or delay the development and progress of ARC/ARM. The efforts should include identifying the right nutrient(s), defining useful levels of the nutrient(s), and determining the age when the supplementation should begin.

Dietary patterns in the Southampton Women's Survey

OBJECTIVE

Dietary pattern analysis is receiving increasing attention as a means of summarizing the multidimensional nature of dietary data. This research aims to compare principal component analysis (PCA) and cluster analysis using dietary data collected from young women in the UK.

DESIGN

Diet was assessed using a 100-item interviewer-administered food frequency questionnaire. PCA and cluster analysis were used to examine dietary patterns.

SETTING

Southampton, UK.

SUBJECTS

A total of 6125 non-pregnant women aged 20-34 years.

RESULTS

PCA identified two important patterns: a 'prudent' diet and a 'high-energy' diet. Cluster analysis defined two clusters, a 'more healthy' and a 'less healthy' cluster. There was a strong association between the prudent diet score and the two clusters, such that the mean prudent diet score in the less healthy cluster was -0.73 standard deviations and in the more healthy cluster was +0.83 standard deviations; the difference in the high-energy diet score between the two clusters was considerably smaller.

CONCLUSIONS

Both approaches revealed a similar dietary pattern. The continuous nature of the outcome of PCA was considered to be advantageous compared with the dichotomy identified using cluster analysis.

SPONSORSHIP

The study was funded by the Dunhill Medical Trust, the University of Southampton and the Medical Research Council.

Methodological approaches to study dietary patterns in relation to risk of coronary heart disease and stroke

Dietary pattern analysis, which reflects the complexity of dietary intake, has received considerable attention by nutritional epidemiology. For a long time, two general approaches have been used to define these summary variables in observational studies. The exploratory approach is based only on the data of the study, whereas the hypothesis-oriented approach constructs pattern variables based on scientific evidence available before the study. Recently, a new statistical method, reduced rank regression, was applied to nutritional epidemiology that is exploratory by nature, but can use scientific evidence by focusing on disease-related dietary components or biomarkers. Several studies, both observational and clinical, suggest that dietary patterns may predict the risk of CHD and stroke. In the present review, we describe the results of these studies and the available evidence regarding the relationships between dietary patterns and risk of CVD and we discuss limitations and strengths of the statistical methods used to extract dietary patterns.

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

BACKGROUND

Inconsistent associations have been reported between diet and breast cancer.

OBJECTIVE

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

DESIGN

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

RESULTS

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

CONCLUSIONS

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

A Comparison of Three Dietary Pattern Indexes for Predicting Biomarkers of Diet and Disease

OBJECTIVE

Examination of dietary indexes in association with objective biomarkers of dietary intake and chronic disease risk is an important step in their validation. We compared three dietary pattern indexes-Healthy Eating Index (HEI), Recommended Foods Score (RFS-24 hour recall), and Dietary Diversity Score for recommended foods (DDS-R)-for their ability to predict biomarkers of dietary intake, obesity, cardiovascular disease, and diabetes.

METHODS

We used dietary and laboratory data from the third National Health and Nutrition Examination Survey to study these associations in 8719 disease-free adults aged > or =20 y. The HEI, developed by the USDA, was a sum of scores on consideration of ten individual components; the RFS was a sum of all recommended foods (lean meat, poultry and fish, whole grains, fruits and juices, low-fat dairy, and vegetables) mentioned in the recall; the DDS-R examined whether or not a recommended food was mentioned from each of the five major food groups. The independent association of the dietary pattern indexes with body mass index (BMI), blood pressure, and serum concentrations of several biomarkers were examined using regression methods to adjust for multiple covariates.

RESULTS

All indexes were strong independent positive predictors of serum concentrations of vitamin C, E, folate, and all carotenoids (p < or = 0.00001), except lycopene, and were negative predictors of BMI, serum homocysteine, C-reactive protein, plasma glucose, and hemoglobin A1C (p < 0.05). The RFS and DDS-R were inversely associated with blood pressure and serum cholesterol (p < or = 0.03).

CONCLUSIONS

The RFS and DDS-R performed as well or better than the HEI for predicting serum concentration of nutrients and biomarkers of disease risk.