Food eating patterns and health: a reexamination of the Ten-State and HANES I surveys

Prospective Associations between Dietary Patterns and Abdominal Obesity in Middle-Aged and Older Korean Adults

This study aimed to identify major dietary patterns associated with abdominal obesity in middle-aged and older Korean adults. Data from the Korean Genome and Epidemiology Study were used. A total of 48,037 Korean adults aged ≥40 years without abdominal obesity at baseline were followed-up. Dietary assessment was conducted using a validated 106-item food-frequency questionnaire, and dietary patterns were identified using factor analysis. Abdominal obesity was defined as a waist circumference of ≥90 cm for men and ≥85 cm for women, according to the Korean Society for the Study of Obesity. Multivariable Cox proportional-hazards models were used to calculate the hazard ratios (HRs) and 95% confidence intervals (CIs) for the future risk of abdominal obesity for each dietary pattern after adjusting for potential covariates. After an average follow-up of 4.89 years, we reported 5878 cases (1932 men and 3946 women) of abdominal obesity. Based on factor analysis, three major dietary patterns were identified in both men and women: the "healthy", "coffee and sweets", and "multi-grain" patterns. In the fully adjusted model, the "healthy" pattern was inversely associated with the incidence of abdominal obesity (HR for fourth vs. first quartile: 0.86; 95% CI: 0.75-0.98; p for trend = 0.0358 for men; HR for fourth vs. first quartile: 0.90; 95% CI: 0.83-0.99; p for trend = 0.0188 for women), whereas the "coffee and sweets" pattern was positively associated with it (HR for fourth vs. first quartile: 1.23; 95% CI: 1.08-1.40; p for trend = 0.0495 for men; HR for fourth vs. first quartile: 1.14; 95% CI: 1.04-1.25; p for trend = 0.0096 for women). In contrast, the "multi-grain" pattern in men and women showed no significant association with the incidence of abdominal obesity. Diets rich in colorful vegetables, seaweeds, mushrooms, tubers, fruits, soy products, and fish and low in coffee, sweets, and oils/fats might be favorable for reducing the future risk of abdominal obesity, particularly in middle-aged and older Korean adults.

Exploration of the Principal Component Analysis (PCA) Approach in Synthesizing the Diet Quality of the Malaysian Population

(1) Background: One of the most main dietary assessments is through a posteriori application. Although extensive research has incorporated dietary assessment of a population through a posteriori application, this study is the first to examine the Malaysian population and use an a posteriori method and principal component analysis (PCA) to assess the dietary patterns of the Malaysian population. The correlation between all dietary patterns derived via PCA and selected nutrient intake were determined in this sample of study; (2) Methods: A total of 3063 respondents (18 to 59 years old) covering Peninsular Malaysia, Sabah, and Sarawak, participated in this study. PCA was applied on the food frequency questionnaire collected from the respondents, and descriptive statistics and PCA were performed using SPSS version 21; (3) Results: Six patterns were identified: "traditional", " prudent", " modern", "western", "Chinese", and "combination" diets. All together, these six patterns were able to explain 45.9% of the total variability. Few components derived from the factor loadings showed positive association with several nutrient markers. The traditional dietary pattern showed a moderate, positive correlation with total protein and total sugar intake, there was a significant moderate correlation between the prudent dietary pattern and dietary fibre, and there was a moderate positive association between the Chinese dietary pattern and total energy; and (4) Conclusions: The exploration of the PCA approach above may provide justification for assessment of dietary patterns rather than reliance on single nutrients or foods to identify potential connections to overall nutritional wellbeing as well as to explore the diet-disease relationship. However, study of pattern analysis must be conducted among the Malaysian population to produce validity and reproducibility for this dietary approach in light of the numerous methodological issues that arise when performing PCA.

Healthy and unhealthy dietary patterns and the risk of chronic disease: an umbrella review of meta-analyses of prospective cohort studies

We aimed to fully review the association of empirical dietary patterns with the risk of non-communicable chronic diseases and to rate the quality of the evidence. Published meta-analyses of observational studies investigating the association of empirically derived dietary patterns with the risk of chronic diseases were identified by searching PubMed and Scopus till September 2019. Two independent reviewers extracted the information and rated the quality of the evidence by NutriGrade score. For each meta-analysis, cross-sectional and case–control studies were excluded and then summary relative risk was recalculated by using a random-effects model. Sixteen meta-analyses of prospective cohort studies, reporting eighteen SRR for healthy dietary patterns and sixteen SRR for unhealthy patterns obtained from 116 primary prospective cohort studies with 4·8 million participants, were included. There was moderate quality of evidence for the inverse association of healthy dietary patterns with the risk of type 2 diabetes (T2D), fracture and colorectal and breast cancers. There was also low-quality evidence for the inverse relation between healthy dietary patterns and the risk of all-cause and cardiovascular mortality, depression, CHD and respiratory diseases. There was moderate quality of evidence for a positive association between unhealthy dietary patterns and the risk of T2D, fracture and the metabolic syndrome. Adopting a healthy dietary pattern may reduce the risk of T2D, CHD and premature death. More research is needed for outcomes for which the quality of the evidence was rated low, such as respiratory disease, mental illness and site-specific cancers.

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.

Dietary Patterns in New Zealand Women: Evaluating Differences in Body Composition and Metabolic Biomarkers

The combinations of food consumed together (dietary patterns) may have a greater influence on health than nutrients or food groups consumed independently. This study investigated the relationship between dietary patterns, body composition and metabolic biomarkers of premenopausal New Zealand women from three ethnic groups. In total, 408 New Zealand European, Māori and Pacific women aged 16-45 years participated in the Women's EXPLORE (EXamining Predictors Linking Obesity Related Elements) study. Participants completed a 220-item food frequency questionnaire. Several body composition parameters and metabolic biomarkers were measured. Dietary patterns were extracted by principal component analysis and dietary pattern scores were categorised into tertiles to assess links with other measured parameters. Women with higher scores for the 'refined and processed' pattern were younger, had higher body mass index, total body fat, plasma leptin and plasma insulin (p < 0.001), and lower plasma ghrelin levels (p < 0.05) than women with lower scores. In addition, more Māori (51%) and Pacific (68%) women followed the 'refined and processed' pattern, while more New Zealand European women (40%) followed the 'sweet and savoury snacking' pattern. These data show that dietary pattern analysis is a useful tool to assess links between diet and metabolic health. It further reveals interesting ethnic group-specific differences in dietary pattern use.

Dietary patterns among French-speaking men residing in Montreal, Canada

The purpose of this study was to describe dietary patterns among 1636 French-speaking men residing in Montreal, Canada and to assess sociodemographic and lifestyle characteristics of men adhering to the dietary patterns identified. Participants were population controls from the Prostate Cancer and Environment Study, a case-control study conducted between 2006 and 2011 in Montreal. Information on diet was collected using a food frequency questionnaire, and principal component analysis, a data-driven method and a posteriori method, was used to identify dietary patterns. Three dietary patterns were identified; Healthy, Modified Western – Salty and Modified Western - Sweet patterns accounted for 7.0%, 5.4%, and 3.2% of the variance, respectively. The Healthy pattern was characterized by consumption of fruits, vegetables, vegetable soup, chicken, fish and seafood, cheese, rice, yogurt, and wine. The Modified Western – Salty pattern included high loadings for beef, pork, chicken, hot-dogs or sausages, cold cuts, bacon, barbecue cooking, meat slightly blackened, potatoes, pasta with tomato sauce, pizza, pastries, dark carbonated soft drinks, ice cream, and white bread. The third pattern, labelled as Modified Western - Sweet, had high loadings of cookies, muffins, cakes, pastries, pies, ice cream, fruits and vegetables. In multivariate analyses, the Healthy pattern was positively associated with higher income and education, moderate recreational physical activity and less heavy smoking, and inversely associated with French ancestry. The Modified Western – Salty pattern was positively associated with French, other European, and Latino ancestries, and with married and common-law relationships. Finally, the Modified Western – Sweet pattern was more common among men of French ancestry and users of vitamin/mineral supplements. The Healthy pattern has been frequently observed in other Western populations, but the other two are described for the first time in a study population of men.

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First study of data-driven dietary patterns focussing on men only in Montreal.

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3 dietary patterns: Healthy, Modified Western –Salty, and Modified Western –Sweet.

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The Modified Western – Salty and Modified Western – Sweet patterns are novel.

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

OBJECTIVE

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

METHODS

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

RESULTS

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

CONCLUSION

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

Dietary patterns and successful ageing: a systematic review

PURPOSE

Nutrition is a key determinant of chronic disease in later life. A systematic review was conducted of studies examining dietary patterns and quality of life, physical function, cognitive function and mental health among older adults.

METHODS

Literature searches in MEDLINE complete, Academic Search Complete, CINAHL Complete, Ageline, Global health, PsycINFO, SCOPUS and EMBASE and hand searching from 1980 up to December 2014 yielded 1236 results. Inclusion criteria included dietary pattern assessment via dietary indices or statistical approaches, a sample of community-dwelling adults aged 45 years and over at baseline and a cross-sectional or longitudinal study design. Exclusion criteria included a single 24-h recall of diet, evaluation of single foods or nutrients, clinical or institutionalised samples and intervention studies. Risk of bias was assessed using the six-item Effective Public Health Practice Project's Quality Assessment Tool for Quantitative Studies.

RESULTS

There were 34 articles (11 cross-sectional and 23 longitudinal) included with 23 studies examining dietary indices and 13 studies using empirical analysis. Most studies examined mental health (n = 10) or cognitive function (n = 18), with fewer studies examining quality of life (n = 6) and physical function (n = 8). Although dietary pattern and outcome assessment methods varied, most studies reported positive associations between a healthier diet and better health outcomes.

CONCLUSION

Overall, the number of studies using dietary patterns to investigate diet and successful ageing is small, and further investigation in longitudinal studies is needed, particularly for quality-of-life outcomes. This review provides support for the importance of a healthy diet for the ageing population globally.

Changes of dietary patterns during participation in a web-based weight-reduction programme

Objective

To examine the weight-loss success associated with distinct dietary patterns and to determine changes of these dietary patterns during participation in a web-based weight-reduction programme.

Design

Factor analysis was used to identify the dietary patterns of twenty-two food groups that were administered in 14 d dietary protocols at baseline and after 3 months. Successful weight loss (≥5 % of initial weight) and BMI were calculated. Logistic regression analyses were used to assess the rates of weight-loss success from each dietary pattern and changing or remaining in the initial dietary pattern. A generalised linear mixed model was used to estimate the effects of changing or staying in a dietary pattern on change in BMI.

Subjects

Adults (n 1635) aged 18–81 years.

Setting

Users of a web-based weight-reduction programme (2006–2012).

Results

Participants who aligned to a healthful dietary pattern at baseline (OR=1·8; 95 % CI 1·5, 2·3) and after 3 months (OR=1·5; 95 % CI 1·2, 1·9) had a greater chance of successfully losing weight. After adjusting for age, sex, initial dietary pattern and BMI, participants who started with or changed to the healthful dietary pattern had a greater chance of being successful (OR=1·4; 95 % CI 1·1, 1·7) and a higher BMI reduction of 0·30 (95 % CI 0·2, 0·5) kg/m2 compared with those who started with or changed to the energy-dense or high-carbohydrate dietary pattern.

Conclusions

A favourable healthful dietary pattern at the beginning and after 3 months was positively associated with anthropometry. However, successful weight loss was feasible in each dietary pattern.

Four major dietary patterns identified for a target-population of adults residing in Newfoundland and Labrador, Canada

Background

Very limited nutritional epidemiological studies conducted to explore the unique dietary exposure in Newfoundland and Labrador (NL). This study aims to identify and characterize major dietary patterns in the target-population from general adult NL residents and assess the associations with selected demographic factors.

Methods

A total of 192 participants, aged 35–70 years, completed and returned a food-frequency questionnaire (FFQ) and participated in a telephone interview to collect demographic information. Dietary patterns were identified by common factor analysis. Univariate and multivariate linear regression analyses were used to assess determinants of the different food consumption patterns. Pearson’s correlation coefficients were calculated for food scores of each pattern, total energy, and energy-adjusted nutrient intakes.

Results

Factor analyses identified four dietary patterns, which were labeled as “Meat”, “Vegetable/fruit”, “Fish”, and “Grain” patterns. In combination, the four dietary patterns explained 63% of the variance in dietary habits of the study population. Multivariate linear regression analysis indicated an increasing trend of factor scores for Meat and Grain pattern with age. Male participants were found to be more likely to choose the Meat and Fish patterns. Current smokers and those married/living together tend to choose the Grain pattern. Pearson’s correlation coefficients showed positive correlations between fat and cholesterol and the Meat pattern, fiber and the Vegetable/fruits pattern, protein and the Fish pattern, and carbohydrates and the Grain pattern.

Conclusion

This study derived four dietary patterns and obtained their significant associations with specific demographic characteristics in this population. It identified one dietary consumption pattern (Fish) not yet seen in other studied populations. These findings will update the current dietary-health information published in this province, and contribute to further research into the association between dietary practices and health.

Heritability of dietary food intake patterns

The quality and quantity of food intake affect body weight, but little is known about the genetics of such human dietary intake patterns in relation to the genetics of BMI. We aimed to estimate the heritability of dietary intake patterns and genetic correlation with BMI in participants of the Erasmus Rucphen Family study. The study included 1,690 individuals (42 % men; age range, 19-92), of whom 41.4 % were overweight and 15.9 % were obese. Self-report questionnaires were used to assess the number of days (0-7) on which participants consumed vegetables, fruit, fruit juice, fish, unhealthy snacks, fastfood, and soft drinks. Principal component analysis was applied to examine the correlations between the questionnaire items and to generate dietary intake pattern scores. Heritability and the shared genetic and shared non-genetic (environmental) correlations were estimated using the family structure of the cohort. Principal component analysis suggested that the questionnaire items could be grouped in a healthy and unhealthy dietary intake pattern, explaining 22 and 18 % of the phenotypic variance, respectively. The dietary intake patterns had a heritability of 0.32 for the healthy and 0.27 for the unhealthy pattern. Genetic correlations between the dietary intake patterns and BMI were not significant, but we found a significant environmental correlation between the unhealthy dietary intake pattern and BMI. Specific dietary intake patterns are associated with the risk of obesity and are heritable traits. The genetic factors that determine specific dietary intake patterns do not significantly overlap with the genetic factors that determine BMI.

Dietary patterns as predictors of prostate cancer in Jamaican men

Studies of diet and prostate cancer have focused primarily on food and nutrients; however, dietary patterns examine the overall diet, particularly foods eaten in combination, and risk of disease. We evaluated the association of dietary patterns and prostate cancer and low- and high-grade subgroups in Jamaican men. In a case-control study, we enrolled 243 incident cases and 273 urology controls in Jamaican clinics, March 2005-July 2007. Dietary patterns were identified using principal component analysis. Four food patterns were identified: a "vegetable and legume" pattern, a "fast food" pattern, a "meat" pattern, and a "refined carbohydrate" pattern. Men in the highest tertile for the refined carbohydrate pattern, characterized by high intakes of rice, pasta, sugar sweetened beverages, and sweet baked foods were at increased risk of total prostate cancer [odds ratio (OR) = 2.02; 95% confidence interval (CI) = 1.05-3.87 (Ptrend = 0.029)] and low-grade disease [OR = 2.91; 95% CI = 1.18-7.13 (Ptrend = 0.019)] compared with men in the lowest tertile. The vegetable and legumes pattern (healthy), meat pattern, or fast food pattern were not associated with prostate cancer risk. These data suggest a carbohydrate dietary pattern high in refined carbohydrates may be a risk factor for prostate cancer in Jamaican men.

Dietary patterns are associated with disease risk among participants in the Women's Health Initiative Observational Study

Coronary heart disease (CHD) is the leading cause of death in women. A nested case-control study tested whether dietary patterns predicted CHD events among 1224 participants in the Women's Health Initiative-Observational Study (WHI-OS) with centrally confirmed CHD, fatal or nonfatal myocardial infarct compared to 1224 WHI-OS controls matched for age, enrollment date, race/ethnicity, and absence of CHD at baseline or follow-up. The first six principal components explained >75% of variation in dietary intakes and K-mean analysis based on these six components produced three clusters. Diet cluster 1 was rich in carbohydrate, vegetable protein, fiber, dietary vitamin K, folate, carotenoids, α-linolenic acid [18:3(n-3)], linoleic acid [18:2(n-6)], and supplemental calcium and vitamin D. Diet cluster 2 was rich in total and animal protein, arachidonic acid [20:4(n-6)], DHA [22:6(n-3)], vitamin D, and calcium. Diet cluster 3 was rich in energy, total fat, and trans fatty acids (all P < 0.01). Conditional logistic regression analysis demonstrated diet cluster 1 was associated with lower CHD risk than diet cluster 2 (reference group) adjusted for smoking, education, and physical activity [OR = 0.79 (95% CI = 0.64, 0.99); P = 0.038]. This difference was not significant after adjustment for BMI and systolic blood pressure. Diet cluster 3 was associated with higher CHD risk than diet cluster 2 [OR = 1.28 (95% CI = 1.04, 1.57); P = 0.019], but this difference did not remain significant after adjustment for smoking, education, and physical activity. Within this WHI-OS cohort, distinct dietary patterns may be associated with subsequent CHD outcomes.

Uso do método Grade of Membership na identificação de perfis de consumo e comportamento alimentar de adolescentes do Rio de Janeiro, Brasil

Com objetivo de identificar perfis de consumo e de comportamentos alimentares e descrever suas prevalências, aplicou-se o método Grade of Membership em dados de um inquérito sobre fatores de risco à saúde de adolescentes do ensino fundamental da cidade do Rio de Janeiro, Brasil (N = 1.632). Foram gerados quatro perfis: perfil "A" (12,1%), caracterizado pelo consumo frequente de todos os alimentos marcadores de dieta saudável, menos frequente dos alimentos não saudáveis e pela presença de comportamentos alimentares saudáveis; perfil "B" (45,8%), marcado pelo hábito de realizar o desjejum e três refeições/dia, consumo menos frequente de legumes e frutas e de cinco dos marcadores de alimentação não saudável; perfil "C" (22,8%), ausência de comportamentos alimentares saudáveis e pelo consumo menos frequente de legumes, frutas, leite, embutidos, biscoitos e refrigerantes; e perfil "D", caracterizado pelo consumo frequente de todos os alimentos não saudáveis e menos frequente de legumes e frutas. Os resultados apontam para a necessidade de promoção da alimentação saudável nesta população.

Padrões alimentares de adolescentes obesos e diferentes repercussões metabólicas

OBJETIVO: Avaliar a associação de padrões alimentares com alterações metabólicas em adolescentes obesos. MÉTODOS: Estudo transversal envolvendo 76 estudantes (ambos os sexos, 14-19 anos, IMC³P95 e Tanner ³4) de escolas públicas da cidade de São Paulo, Brasil. Foram coletados dados antropométricos e bioquímicos, e aplicados questionários com informações sociodemográficas e registro alimentar de 4 dias, entre 2006 e 2007. Escores fatoriais foram obtidos na análise fatorial e, após ajustes, três padrões alimentares identificados foram associados a fatores de risco biológico por regressão linear múltipla. RESULTADOS: O padrão Tradicional (arroz e massas, feijões, carnes vermelhas, embutidos, óleos e doces) foi positivamente associado com insulina, glicemia e triglicérides e negativamente associado com lipoproteína de alta densidade. O padrão Em Transição (peixe, aves, ovos, pães, manteiga, leite e derivados, hortaliças, frutas, sucos de frutas e açúcar refinado) apresentou as mesmas associações, além de associação similar com a pressão arterial diastólica. O padrão Fast Food (cafeteria, hambúrguer, maionese, bolacha, bolos e tortas, chocolate e refrigerantes) apresentou associação positiva com o colesterol, lipoproteína de baixa densidade e pressão arterial sistólica e diastólica, e associação negativa com insulina e lipoproteína de alta densidade. CONCLUSÃO: Os padrões Tradicional e Em transição apresentaram associações diferentes com o metabolismo lipídico e glicídico quando comparados com o padrão Fast Food. Os três padrões podem ser considerados obesogênicos, porém o padrão Fast Food pareceu ser o mais aterogênico e promotor de hipertensão arterial.

Dietary patterns are associated with metabolic syndrome in an urban Mexican population

The role that diet plays in the origin of metabolic syndrome (MetS) is not completely understood. Certain foods and nutrients have been established as dietary risk factors for MetS. However, the dietary patterns associated with MetS risk have been minimally studied with factor analysis. Our objective in this study was to use exploratory factor analysis to examine whether particular dietary patterns are related to risk of MetS in Mexican adults. We characterized the dietary patterns among 5240 men and women aged 20-70 y in the Health Workers Cohort Study. Information on participants' sociodemographic conditions and physical activity was collected via self-administered questionnaires. We also obtained anthropometric and clinical measurements and fasting blood samples for biochemical analyses. In a cross-sectional analysis, we examined dietary patterns in relation to MetS, defined using criteria from the Adult Treatment Panel III. Factor analysis revealed 3 major dietary patterns: prudent, Western, and high protein/fat. The prevalence of MetS was 26.6%. After adjustment for potential confounders, compared with participants in the lowest tertile of the Western pattern, those in the highest tertile had higher odds ratios (OR) for high fasting glucose (OR, 1.67; 95% CI: 1.36-2.06), low serum HDL cholesterol (OR, 1.55; 95% CI: 1.31-1.83), and MetS (OR, 1.56; 95% CI, 1.31-1.88). However, we found no significant associations between other patterns and MetS. In summary, a diet high in soft drinks, refined grains, corn tortillas, pastries, seafood, and whole grains was associated with MetS risk. This result emphasizes the importance of preventive nutrition interventions.

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.

Dietary patterns in middle-aged Irish men and women defined by cluster analysis

Objectives:

To identify and characterise dietary patterns in a middle-aged Irish population sample and study associations between these patterns, sociodemographic and anthropometric variables and major risk factors for cardiovascular disease.

Design:

A cross-sectional study.

Subjects and methods:

A group of 1473 men and women were sampled from 17 general practice lists in the South of Ireland. A total of 1018 attended for screening, with a response rate of 69%. Participants completed a detailed health and lifestyle questionnaire and provided a fasting blood sample for glucose, lipids and homocysteine. Dietary intake was assessed using a standard food-frequency questionnaire adapted for use in the Irish population. The food-frequency questionnaire was a modification of that used in the UK arm of the European Prospective Investigation into Cancer study, which was based on that used in the US Nurses' Health Study. Dietary patterns were assessed primarily by K-means cluster analysis, following initial principal components analysis to identify the seeds.

Results:

Three dietary patterns were identified. These clusters corresponded to a traditional Irish diet, a prudent diet and a diet characterised by high consumption of alcoholic drinks and convenience foods. Cluster 1 (Traditional Diet) had the highest intakes of saturated fat (SFA), monounsaturated fat (MUFA) and percentage of total energy from fat, and the lowest polyunsaturated fat (PUFA) intake and ratio of polyunsaturated to saturated fat (P:S). Cluster 2 (Prudent Diet) was characterised by significantly higher intakes of fibre, PUFA, P:S ratio and antioxidant vitamins (vitamins C and E), and lower intakes of total fat, MUFA, SFA and cholesterol. Cluster 3 (Alcohol & Convenience Foods) had the highest intakes of alcohol, protein, cholesterol, vitamin B12, vitamin B6, folate, iron, phosphorus, selenium and zinc, and the lowest intakes of PUFA, vitamin A and antioxidant vitamins (vitamins C and E). There were significant differences between clusters in gender distribution, smoking status, physical activity, body mass index, waist circumference and serum homocysteine concentrations.

Conclusion:

In this general population sample, cluster analysis methods yielded two major dietary patterns: prudent and traditional. The prudent dietary pattern is associated with other health-seeking behaviours. Study of dietary patterns will help elucidate links between diet and disease and contribute to the development of healthy eating guidelines for health promotion.

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.

The story of the Interdepartmental Committee on Nutrition for National Defense's North American activities (1958-1970)

Of the 48 nutrition surveys conducted by the ICNND/Office of International Research/CDC Nutrition Programs during the years 1956-1970, 20 were performed in North America. Native Americans were surveyed in Alaska in 1958 and in Montana in 1961. In partnership with INCAP (Institute for Central America and Panama), six Central American countries were surveyed in 1965 through 1967. As mandated by Congress, 10 American states and one major city were surveyed during 1968-1970. Civilian and some military populations were included in these surveys. Teams of health, agriculture, and nutrition specialists drawn from academic institutions and from national and international agencies conducted each survey. We followed the methodology, standards, and definitions developed by ICNND in its Manual for Nutrition Surveys. Detailed findings, results and recommendations were published in a series of reports printed by the U.S. Government Printing Office. All 20 of the North American surveys found similar groups at risk of nutrition problems, including dental caries, goiter, growth retardation, female obesity, and "low" levels of hemoglobin, vitamin A, thiamin, and riboflavin. Survey recommendations followed common themes: nutrition education, nutrient fortification of food or water, expanded supplemental food programs, provision of safe water supplies, proper sanitation and food safety, and enhanced nutrient content of basic foods.

Food patterns measured by factor analysis and anthropometric changes in adults

BACKGROUND

Sixty-five percent of US adults are overweight, and 31% of these adults are obese. Obesity results from weight gains over time; however, dietary determinants of weight gain remain controversial.

OBJECTIVE

Our objective was to examine whether food patterns derived from exploratory factor analysis are related to anthropometric changes. We hypothesized that we would derive a healthy food pattern and that it would predict smaller changes in body mass index (BMI; in kg/m(2)) and waist circumference (in cm) than would other food patterns in models adjusted for baseline anthropometric measures.

DESIGN

The subjects were 459 healthy men and women participating in the Baltimore Longitudinal Study of Aging. Diet was assessed by using 7-d dietary records, from which 40 food groups were formed and entered into a factor analysis.

RESULTS

Six food patterns were derived. Factor 1 (reduced-fat dairy products, fruit, and fiber) was most strongly associated with fiber (r = 0.39) and loaded heavily on reduced-fat dairy products, cereal, and fruit and loaded moderately on fruit juice, nonwhite bread, nuts and seeds, whole grains, and beans and legumes. In a multivariate-adjusted model in which the highest and lowest quintiles were compared, factor 1 was inversely associated with annual change in BMI (beta = -0.51; 95% CI: -0.82, -0.20; P < 0.05; P for trend < 0.01) in women and inversely associated with annual change in waist circumference (beta = -1.06 cm; 95% CI: -1.88, -0.24 cm; P < 0.05; P for trend = 0.04) in both sexes.

CONCLUSION

Our results suggest that a pattern rich in reduced-fat dairy products and high-fiber foods may lead to smaller gains in BMI in women and smaller gains in waist circumference in both women and men.

Dietary patterns and changes in body mass index and waist circumference in adults

BACKGROUND

Obesity has increased > 20% in the past decade in the United States, and more than one-half of US adults are overweight or obese.

OBJECTIVE

Our objective was to further elucidate the nutritional etiology of changes in body mass index (BMI; in kg/m(2)) and waist circumference by dietary intake pattern. We hypothesized that a healthy dietary pattern would lead to smaller changes in BMI and waist circumference than would other dietary patterns.

DESIGN

Subjects were 459 healthy men and women participating in the ongoing Baltimore Longitudinal Study of Aging. Diet was assessed with the use of 7-d dietary records, from which 41 food groups were created and entered into a cluster analysis.

RESULTS

Five dietary patterns were derived (healthy, white bread, alcohol, sweets, and meat and potatoes). The mean annual change in BMI was 0.30 +/- 0.06 for subjects in the meat-and-potatoes cluster and 0.05 +/- 0.06 for those in the healthy cluster (P < 0.01). The mean annual change in waist circumference was more than 3 times as great for subjects in the white-bread cluster (1.32 +/- 0.29 cm) as for those in the healthy cluster (0.43 +/- 0.27 cm) (P < 0.05).

CONCLUSIONS

Consuming a diet high in fruit, vegetables, reduced-fat dairy, and whole grains and low in red and processed meat, fast food, and soda was associated with smaller gains in BMI and waist circumference. Because foods are not consumed in isolation, dietary pattern research based on natural eating behavior may be useful in understanding dietary causes of obesity and in helping individuals trying to control their weight.

An approach to construct simplified measures of dietary patterns from exploratory factor analysis

Exploratory factor analysis might work well in elucidating the major dietary patterns prevailing in specific study populations. However, patterns extracted in one study population and their associations with disease risk cannot be reproduced with this data-specific method in other study populations. To construct less population-dependent pattern variables of similar content as original exploratory patterns, we proposed to derive so-called simplified pattern variables. They represent the sum of the unweighted standardised food variables which loaded high at the pattern of interest. Data from the European Prospective Investigation into Cancer and Nutrition (EPIC)-Potsdam study suggest that these simplified pattern variables might adequately approximate factor analysis-based dietary patterns. A simplified pattern variable based on the six highest loading food variables showed a correlation >0.95 with the originally derived factor score, which consisted of forty-seven food variables. Moreover, simplified pattern variables might adequately approximate patterns across different study populations. A simplified pattern variable showed similar factor loadings, ranging from 0.34 to 0.52, as well as similar associations with nutrient intake as a 'western' pattern originally reported from an US study population. These simplified pattern variables can subsequently be used to study pattern associations with disease risk, especially in multi-centre studies. It is therefore an approach that might overcome one of the most frequently claimed limitations of factor analyses applied in epidemiology: their non-comparable risk estimates.

A prospective study of variety of healthy foods and mortality in women

BACKGROUND

To assess the overall influence of diet on health and disease in epidemiological studies, the habitual diet of the study participants has to be captured as a pattern rather than individual foods or nutrients. The simplest way to describe dietary preferences is to separate foods considered beneficial to health from foods considered to promote disease, and separate individuals on the basis of their regular consumption of these foods.

METHODS

We used data from 59 038 women participating in the prospective Mammography Screening Cohort in Sweden to investigate the influence of variety of healthy and less healthy foods on all-cause and cause-specific mortality.

RESULTS

Women who followed a healthy diet defined as consumption of a high variety of fruits, vegetables, whole grain breads, cereals, fish, and low fat dairy products had a significantly lower mortality than women who consumed few of these foods (3710 deaths total). Women who reported regularly consuming 16-17 healthy foods had a 42% lower all-cause mortality (95% CI: 32-50%) compared to women reporting consumption of 0-8 healthy foods with any regularity (P for trend <0.0001). For each additional healthy food consumed the risk of death was about 5% lower (95% CI: 4-6%). Cardiovascular mortality was particularly low among women who reported consuming a high variety of healthy foods. A less healthy diet defined as consumption of a high variety of red meats, refined carbohydrates and sugars, and foods high in saturated or trans fats was not directly associated with a higher overall mortality. However, women who reported consuming many less healthy foods were significantly more likely to die from cancer than those who consumed few less healthy foods.

CONCLUSIONS

A healthy diet can affect longevity. It appears more important to increase the number of healthy foods regularly consumed than to reduce the number of less healthy foods regularly consumed.

Dietary patterns of Australian adults and their association with socioeconomic status: results from the 1995 National Nutrition Survey

OBJECTIVE

To describe dietary patterns among men and women in the Australian population, and to explore how these varied according to socioeconomic status (SES).

DESIGN

A cross-sectional self-report population survey, the 1995 Australian National Nutrition Survey (NNS), was used.

SETTING

Private dwelling sample, covering urban and rural areas across Australia.

SUBJECTS

Data provided by 6680 adults aged 18-64 who participated in the NNS were used in the analyses.

METHODS

Factor analyses were used to analyse data from a Food Frequency Questionnaire (FFQ) completed by participants. Associations between SES and dietary pattens were assessed using ANOVA.

RESULTS

Separate factor analyses of the FFQ data for men and women revealed 15 factors, accounting for approximately 50% of the variance in both men's and women's dietary patterns. Several gender and SES differences in food patterns were observed. Lower SES males more frequently consumed 'tropical fruits', 'protein foods', and 'offal and canned fish', while high SES males more often ate 'breakfast cereals' and 'wholemeal bread'. Lower SES females more often ate 'traditional vegetables', 'meat dishes' and 'pasta, rice and other mixed foods', while high SES females more frequently ate 'ethnic vegetables' and 'breakfast cereal/muesli'.

CONCLUSIONS

These findings contribute to a better understanding of the dietary patterns that underscore gender-specific SES differences in nutrient intakes. Analyses of the type employed in this study will facilitate the development of interventions aimed at modifying overall eating patterns, rather than specific components of the diet.

Dietary pattern analysis: a new direction in nutritional epidemiology

Recently, dietary pattern analysis has emerged as an alternative and complementary approach to examining the relationship between diet and the risk of chronic diseases. Instead of looking at individual nutrients or foods, pattern analysis examines the effects of overall diet. Conceptually, dietary patterns represent a broader picture of food and nutrient consumption, and may thus be more predictive of disease risk than individual foods or nutrients. Several studies have suggested that dietary patterns derived from factor or cluster analysis predict disease risk or mortality. In addition, there is growing interest in using dietary quality indices to evaluate whether adherence to a certain dietary pattern (e.g. Mediterranean pattern) or current dietary guidelines lowers the risk of disease. In this review, we describe the rationale for studying dietary patterns, and discuss quantitative methods for analysing dietary patterns and their reproducibility and validity, and the available evidence regarding the relationship between major dietary patterns and the risk of cardiovascular disease.

[Food consumption scores and serum lipids levels in the population of São Paulo, Brazil]

OBJECTIVE

To study food patterns assessed using scores of consumption and their relationship with serum total cholesterol (TOTAL-C), low density lipoprotein-cholesterol (LDL-C) and high density lipoproteins (HDL-C) concentration in the population of the metropolitan area of São Paulo, Brazil.

METHODS

Data on food frequency consumption (FFC), serum lipids, and other covariates were available for a representative sample of 1,045 adults. A 12-month retrospective food frequency questionnaire was used. FFC was assessed using scores of consumption, which was obtained by grouping food according to their composition into two large groups: score I (known as risk food for cardiovascular diseases) and score II (known as healthy food). The association between the scores and serum blood lipoprotein levels among the study population was analyzed through multiple linear regression analyses. Modeling step-wise techniques were used to enter the covariates into the linear models.

RESULTS

Increasing mean levels of TOTAL-C and LDL-C were seen from the lowest through the highest quintile of score I when compared to the score II, where decreasing mean levels of TOTAL-C and LDL-C were observed from the lowest to the highest quintile. The results of the linear regression analyses between serum TOTAL-C and LDL-C levels for both FFC score I and score II, after multivariate adjusting, showed a significant positive relationship with score I and a significant and inverse relationship with score II.

CONCLUSIONS

In population studies, FFC analyses through scores can be the choice method to evaluate the quality of diet and its potential effect on serum levels of TOTAL-C and LDL-C.

Dietary patterns and their association with food and nutrient intake in the European Prospective Investigation into Cancer and Nutrition (EPIC)-Potsdam study

Dietary pattern analysis has recently received growing attention, as it might be more appropriate in studies of diet-disease associations than the single food or nutrient approach that has dominated past epidemiological research. Factor analysis is a technique which is commonly used to identify dietary patterns within study populations. However, the ability of factor solutions to account for variance of food and nutrient intake has so far remained unclear. The present study therefore explored the statistical properties of dietary patterns with regard to the explained variance. Food intake of 8975 men and 13 379 women, assessed by a food-frequency questionnaire, was aggregated into forty-seven separate food groups. Dietary patterns were identified by principal component analysis and subsequent varimax rotation. Seven factors were retained for both men and women, which accounted for about 31 % of the total variance. The explained variance was relatively high (>40 %) for cooked vegetables, sauce, meat, dessert, cake, bread other than wholemeal, raw vegetables, processed meat, high-fat cheese, butter and margarine. Factor scores were used to investigate associations between the factors and nutrient intake. The patterns accounted for relatively large proportions of variance of energy and macronutrient intake, but for less variance of alcohol and micronutrient intake, especially of retinol, beta-carotene, vitamin E, Ca and ascorbic acid. In addition, factors were related to age, BMI, physical activity, education, smoking and vitamin and mineral supplement use.

Validation of a dietary pattern approach for evaluating nutritional risk: the Framingham Nutrition Studies

OBJECTIVE

To validate the use of cluster analysis for characterizing population dietary patterns.

DESIGN

Cluster analysis was applied to a food frequency questionnaire to define dietary patterns. Independent estimates of nutrient intake were derived from 3-day food records. Heart disease risk factors were assessed using standardized protocols in a clinic setting.

SETTING

Adult women (n = 1,828) participating in the Framingham Offspring-Spouse study.

STATISTICAL ANALYSES

Age-adjusted mean nutrient intakes were determined for each cluster. Analysis of covariance was used to evaluate pairwise differences in intake across clusters. Compliance with published recommendations was determined for selected heart disease risk factors. Differences in age-adjusted compliance across clusters were evaluated using logistic regression.

RESULTS

Cluster analysis identified 5 distinct dietary patterns characterized by unique food behaviors and significantly different nutrient intake profiles. Patterns rich in fruits, vegetables, grains, low-fat dairy, and lean protein foods resulted in higher nutrient density. Patterns rich in fatty foods, added fats, desserts, and sweets were less nutrient-dense. Women who consumed an Empty Calorie pattern were less likely to achieve compliance with clinical risk factor guidelines in contrast to most other groups of women.

CONCLUSIONS

Cluster analysis is a valid tool for evaluating nutrition risk by considering overall patterns and food behaviors. This is important because dietary patterns appear to be linked with other health-related behaviors that confer risk for chronic disease. Therefore, insight into dietary behaviors of distinct clusters within a population can help to design intervention strategies for prevention and management of chronic health conditions including obesity and cardiovascular disease.

Food intake patterns and gallbladder disease in Mexican Americans

OBJECTIVE

Results of previous studies on diet and gallbladder disease (GBD), defined as having gallstones or having had surgery for gallstones, have been inconsistent. This research examined patterns of food intake in Mexican Americans and their associations with GBD.

DESIGN

Cross-sectional.

SUBJECTS

The study population included 4641 Mexican Americans aged 20-74 years who participated in the 1988-94 third National Health and Nutrition Examination Survey (NHANES III). GBD was diagnosed by ultrasound. Food intake patterns were identified by principal components analysis based on food frequency questionnaire responses. Component scores representing the level of intake of each pattern were categorized into quartiles, and prevalence odds ratios (POR) were estimated relative to the lowest quartile along with 95% confidence intervals (CI).

RESULTS

There were four distinct patterns in women (vegetable, high calorie, traditional, fruit) and three in men (vegetable, high calorie, traditional). After age adjustment, none were associated with GBD in women. However, men in the third (POR = 0.42, 95%CI 0.21-0.85) and fourth (POR = 0.53, 95%CI 0.28-1.01) quartiles of the traditional intake pattern were half as likely to have GBD as those in the lowest quartile.

CONCLUSIONS

These findings add to a growing literature suggesting dietary intake patterns can provide potentially useful and relevant information on diet-disease associations. Nevertheless, methods to do so require further development and validation.

Genetic and environmental influences on eating patterns of twins aged >/=50 y

BACKGROUND

Clinicians and researchers could benefit from a greater understanding of the role of genetic and environmental factors in human eating behavior.

OBJECTIVE

Our aim was to estimate the relative influence of genetic and environmental factors on habitual eating patterns in middle-aged and elderly men and women.

DESIGN

Male and female twins (n = 4640) aged >/=50 y completed a mailed version of the National Cancer Institute food-frequency questionnaire. Factor analysis was performed to identify eating patterns among respondents. Estimates of genetic, common environmental (shared by family members), and specific environmental (unique to an individual) influences were obtained for food use, serving size, and consumption frequency by comparing monozygotic and dizygotic twin-pair groups with structural equation analysis.

RESULTS

Two independent eating patterns were identified: the first consisted of items high in fat, salt, and sugar, and the second reflected healthful eating habits. Although the influence of environmental factors was larger, between 15% and 38% of the total variation in pattern 1 and between 33% and 40% in pattern 2 were explained by genetic influences. Models accounting for sex differences in genetic and environmental estimates fit the data significantly better for food use and serving size of foods in eating pattern 1 and for food use in eating pattern 2.

CONCLUSION

Although 60-85% of the variability in eating patterns was associated with environmental factors, genetic influences were also apparent and there was some evidence of sex specificity. These findings may be important in crafting dietary interventions and predicting adherence to these interventions.

Dietary patterns of adults in Québec and their nutritional adequacy

The purpose of this study was to identify dietary patterns among adults in Québec and to determine their relationship to nutritional adequacy of the diet. We used 24-hour food recall data on 2,104 adults from the Québec nutrition survey (1990). Nutritional adequacy was assessed based on the 1990 Nutrition Recommendations for Canadians; dietary patterns were assessed via a factor analysis of the 30 food groups consumed. The three major patterns identified ('high-energy density', 'traditional' and 'health-conscious') explained 18% of the variation in food intake. Only the 'health-conscious' pattern correlated positively with the four chosen indicators of nutritional adequacy. Generally, men scored positively on the 'high-energy density' and the 'traditional' pattern whereas women scored positively on the 'health-conscious' pattern. Aside from sex, scoring was most related to age and education. The use of these patterns to define and target nutrition interventions should be tested in the aim of improving the effectiveness of health promotion.

Dietary patterns of men and women suggest targets for health promotion: the Framingham Nutrition Studies

PURPOSE

The goal of the study was to characterize the dietary patterns of adult men and women.

DESIGN

The study used a cross-sectional analysis of food consumption behaviors and nutrient intake measured from 1984 through 1988.

SETTING

The Framingham Offspring/Spouse Study, Framingham, Massachusetts.

SUBJECTS

The population-based sample comprised 1831 men and 1828 women between 20 and 70 years of age.

MEASURES

Dietary patterns were defined by cluster analyses, which used the estimates of usual daily food intake from food frequency questionnaires, and the patterns were compared with Food Guide Pyramid recommendations. Nutrient intakes were independently estimated from 24-hour recalls and compared with Year 2000 nutrition recommendations.

RESULTS

Cluster analyses identified five groups of men and five groups of women with distinctive dietary patterns. Men differed on intakes of all food groups except vegetables and snacks plus sweetened beverages. Specific dietary behaviors, including low intakes of whole grains, fruits, vegetables, and other complex carbohydrates; high intakes of beer and liquor; and high intakes of high-fat animal foods warrant targeted intervention messages for men. Women's patterns differed across all food groups except red meats and fattier poultry and beer. Dietary behaviors of women that deserve attention include low fruit, vegetable, starch, and dietary intakes; chronic dieting; high alcohol intake; and sources of hidden fats. No cluster met the current recommendations for food and nutrient intake.

CONCLUSIONS

Distinct dietary patterns in Framingham men and women vary in compliance with national nutrition and health policy objectives and provide insights for developing behavioral interventions to improve food and nutrient intake.

Indexes of overall diet quality: a review

This article reviews the published indexes of overall diet quality. Approaches used for measuring overall diet quality include those based on examination of the intake of nutrients, food groups, or a combination of both. A majority of the indexes have been examined in relation to nutrient adequacy only; few have been evaluated for assessment of quality according to current dietary guidelines, namely, a diet relatively low in fat that meets energy and nutrient needs. The indexes of overall diet quality were related to the risk of disease more strongly than individual nutrients or foods.

Maternal eating patterns and birth weight of Mexican American infants

Eating patterns of 549 Mexican American mothers were identified using dietary data from the United States Hispanic Health and Nutrition Examination Survey. These eating patterns were then used to investigate the relationship between maternal diet and infant birth weight. Principle components factor analysis was used to determine the structure of the maternal eating patterns. Seven distinct eating patterns were identified: nutrient dense, traditional, transitional, nutrient dilute, protein rich, high fat dairy, and mixed dishes. Stepwise multiple regression analysis was used to identify those eating patterns associated with birth weight. In addition to eating patterns, regression variables included body mass index, hemoglobin, gestational age at delivery, maternal age, infant gender, acculturation, marital status, income, education, and smoking during pregnancy. Regression results indicated that the nutrient dense (fruits, vegetables, low fat dairy, etc.) and protein rich (low fat meats, processed meats, and dairy desserts, etc.) eating patterns were associated with increased birth weight and that the transitional eating pattern (fats and oils, breads and cereals, high fat meats, sugar, etc.) was associated with decreased birth weight. Study findings suggest that the eating pattern methodology may be an appropriate tool for analyzing food frequency data in the investigation of diet and health relationships and for targeting dietary interventions.

Clustering of dietary variables and other lifestyle factors (Dutch Nutritional Surveillance System)

STUDY OBJECTIVE

The aim was to investigate whether dietary factors cluster in a favourable or unfavourable way and to characterise the groups identified by lifestyle and sociodemographic variables.

DESIGN AND SETTING

This cross sectional study was based on data of the 1987-1988 Dutch national food consumption survey (DNFCS), obtained from a panel by a stratified probability sample of the non-institutionalised Dutch population.

PARTICIPANTS

3781 adults (1802 males and 1979 females) of the DNFCS, aged 19 to 85 years, were studied.

MEASUREMENTS AND MAIN RESULTS

To estimate dietary intake two day food records were used. Lifestyle factors were collected by structured questionnaire and sociodemographic variables were available from panel information. Cluster analysis was used to classify subjects into groups based on similarities in dietary variables. Subsequently, these groups were characterised by sociodemographic and lifestyle factors as well as by the consumption of food groups. Eight clusters were found. In comparison with the guidelines, the dietary quality in four clusters was poor. The cluster with the poorest dietary intake (high intake of fat, cholesterol, and alcohol; low intake of dietary fibre) showed on average a high consumption of animal products (except milk), fats and oils, snacks, and alcoholic beverages, and a low consumption of fruit, potatoes, vegetables, and sugar rich products. Smoking, body mass index, dietary regimen on own initiative, hours of sleep, gender, age, socioeconomic status, and day of the week were found to discriminate among the clusters.

CONCLUSIONS

Cluster analysis resulted in substantial differences in mean nutrient intake and seems useful for dietary risk group identification. Undesirable lifestyle habits were interrelated in some clusters, but an exclusive lifestyle for health risk has not been found.

Dietary behaviour and health in Northern Ireland: an exploration of biochemical and haematological associations

STUDY OBJECTIVE

The aim was to determine the relationships between dietary behaviour and biochemical and haematological measures.

DESIGN

This was a cross sectional population study.

SETTING

The study took place in the general community within Northern Ireland.

SUBJECTS

522 randomly selected adults aged 18-64 years took part (65% of the eligible sample).

MEASUREMENTS AND MAIN RESULTS

Four dietary behaviours were identified using principal components analysis from 7 d weighed dietary records described in terms of mean intake of 41 food groups. Haematological and biochemical analyses were carried out on non-fasting blood samples. Social, personal, and lifestyle information was ascertained through interviewer administered questionnaires. Partial correlations controlled for age and smoking behaviour were calculated. There were significant negative associations between iron status measures and the "traditional" behaviour, while the "meat and two veg" behaviour showed positive associations. There were positive associations between the "cosmopolitan" and "convenience" behaviours and folate status in women. White cell count and platelet levels in women were negatively associated with the "traditional" and "cosmopolitan" behaviours. Total cholesterol levels showed significant negative associations with the "cosmopolitan" behaviour in women and HDL cholesterol levels were positively associated with the "cosmopolitan", "convenience" and "meat and two veg" behaviours.

CONCLUSIONS

Through a multivariate approach to dietary assessment it is possible to identify food combinations that cluster and interact to influence biochemical and haematological indices of health status.

Epidemiologic studies utilizing surveys: accounting for the sampling design

BACKGROUND

Since large-scale health surveys usually have complicated sampling schemes, there is often a question as to whether the sampling design must be considered in the analysis of the data. A recent disagreement concerning the analysis of a body iron stores-cancer association found in the first National Health and Nutrition Examination Survey and its follow-up is used to highlight the issues.

METHODS

We explain and illustrate the importance of two aspects of the sampling design: clustering and weighting of observations. The body iron stores-cancer data are reanalyzed by utilizing or ignoring various aspects of the sampling design. Simple formulas are given to describe how using the sampling design of a survey in the analysis will affect the conclusions of that analysis.

RESULTS

The different analyses of the body iron stores-cancer data lead to very different conclusions. Application of the simple formulas suggests that utilization of the sample clustering in the analysis is appropriate, but that a standard utilization of the sample weights leads to an uninformative analysis. The recommended analysis incorporates the sampling weights in a nonstandard way and the sample clustering in the standard way.

CONCLUSIONS

Which particular aspects of the sampling design to use in the analysis of complex survey data and how to use them depend on certain features of the design. We give some guidelines for when to use the sample clustering and sample weights in the analysis.

Dietary behaviours and sociocultural demographics in Northern Ireland

Subjects aged 16-64 years (592; 258 men and 334 women), randomly selected from the population of Northern Ireland, kept a 7 d weighed record of all food and drink consumed. Social, personal and anthropometric data were also collected. From the weighed records food consumption was described in terms of forty-one food groups. Using principal components analysis, four distinct dietary patterns were generated which were identified as a traditional diet, a cosmopolitan diet, a convenience diet and a 'meat and two veg' diet. These dietary patterns were then correlated with sociocultural, lifestyle and anthropometric variables. It is clear that dietary behaviour is influenced by a number of inter-related sociocultural demographics and that identifiable population groups in Northern Ireland have different dietary behaviours.

Strategies for analyzing nutritional data for epidemiological purposes--conceptual framework

The relation between nutritional factors and health investigated in epidemiological studies are often inconsistent. One of the reasons for such findings can be the improper addressing of the multitude of nutritional dimensions in the specific study situation such as physiological individuality of human beings, different living conditions, or numerous interdependencies between nutritional variables. Epidemiological research in nutrition and health should recognize such facts and work with appropriate study models and adequate data analyses. Instead of investigating heterogeneous populations it is advisable to concentrate on specific "types" of people. Under consideration of the study goals such "types" can be compiled according to physiological properties, e.g., cholesterol sensitivity, or biological-constitutional factors such as body build, life-style entities, or other factors. The variety of nutrition factors far beyond the commonly applied nutrient values can be expressed in integrated indices of "food patterns". Such "food patterns" can be derived in many ways. They can be deduced from theories by using specific criteria, but also explored by modern multivariate statistical analyses. The ways leading to "food patterns" are discussed. The ideas presented and discussed in this paper lead to an improved model for research in the field of nutrition and health with integrated indices of "food patterns" as the critical point. It is assumed that using this approach will generate new insight in the relation of nutrition and health, a currently still diffuse research area.

Incorporation of trans-8- and cis-8-octadecenoic acid isomers in human plasma and lipoprotein lipids

Mixtures of deuterium-labeled trans-8, cis-8 and cis-9-octadecenoic acids (8t-18:1, 8c-18:1, 9c-18:1) were fed as triglycerides (TG) to two adult male subjects. Blood samples were collected sequentially over a 48-hour period. Plasma and lipoprotein lipids were separated by thin layer chromatography and analyzed by gas chromatography-mass spectroscopy. Results indicate (i) absorption of the 8t- and 8c-18:1 isomers were similar to 9c-18:1; (ii) the 8t-18:1 isomer was cleared approximately 30% faster than 9c-18:1 from plasma TG; (iii) cholesterol ester samples contained 8.4 times less 8t-18:1 than 9c-18:1; (iv) incorporation at the 1-acyl phosphatidylcholine (PC) position was higher for 8t-18:1 and 8c-18:1 (2.2 and 1.7 times) than for 9c-18:1; and (v) discrimination at the 2-acyl PC position was 4.6-fold against 8t-18:1 and 1.3-fold against 8c-18:1 compared with 9c-18:1. Discrimination against uptake of the delta-8 isomers in both neutral and phospholipid classes suggests that both 8t- and 8c-18:1 may be preferentially oxidized relative to 9c-18:1. Except for triglycerides, data for each of the lipid classes from total plasma and individual lipoprotein samples were similar. These data indicate that differences for incorporation and turnover of the 8t- and 8c-18:1 isomers relative to 9c-18:1 are not substantially influenced by the lipoprotein classes. The maximum isotopic enrichment detected in the chylomicron triglycerides fractions was 60%, which indicates that a substantial amount of endogenous triglycerides was mobilized during absorption of the deuterated fats.

Metabolism in humans of cis-12,trans-15-octadecadienoic acid relative to palmitic, stearic, oleic and linoleic acids

Mixtures of triglycerides containing deuterium-labeled hexadecanoic acid (16:0), octadecanoic acid (18:0), cis-9-octadecenoic acid (9c-18:1), cis-9,cis-12-octadecadienoic acid (9c, 12c-18:2) and cis-12,trans-15-octadecadienoic acid (12c,15t-18:2) were fed to two young-adult males. Plasma lipid classes were isolated from samples collected periodically over 48 hr. Incorporation and turnover of the deuterium-labeled fats in plasma lipids were followed by gas chromatography-mass spectrometry (GC-MS) analysis of the methyl ester derivatives. Absorption of the deuterated fats was followed by GC-MS analysis of chylomicron triglycerides isolated by ultracentrifugation. Results were the following: (i) endogenous fat contributed about 40% of the total fat incorporated into chylomicron triglycerides; (ii) elongation, desaturation and chain-shortened products from the deuterated fats were not detected; (iii) the polyunsaturated isomer 12c,15t-18:2 was metabolically more similar to saturated and 9c-18:1 fatty acids than to 9c,12c-18:2; (iv) relative incorporation of 9c,12c-18:2 into phospholipids did not increase proportionally with an increase of 9c,12c-18:2 in the mixture of deuterated fats fed; (v) absorption of 16:0, 18:0, 9c-18:1, 9c,12c-18:2 and 12c,15t-18:2 were similar; and (vi) data for the 1- and 2-acyl positions of phosphatidylcholine and for cholesteryl ester fractions reflected the known high specificity of phosphatidylcholine acyltransferase and lecithin:cholesteryl acyltransferase for 9c,12c-18:2. These results illustrate that incorporation of dietary fatty acids into human plasma lipid classes is selectively controlled and that incorporation of dietary 9c,12c-18:2 is limited. These results suggest that nutritional benefits of diets high in 9c,12c-18:2 may be of little value to normal subjects and that the 12c,15t-18:2 isomer in hydrogenated fat is not a nutritional liability at the present dietary level.