Food patterns defined by cluster analysis and their utility as dietary exposure variables: a report from the Malmö Diet and Cancer Study

Clustering of Mediterranean dietary patterns linked with health-related quality of life in adolescents: the EHDLA study

The aim of this cross-sectional study was to analyze the association between adherence to the Mediterranean diet (MedDiet) and its dietary components and health-related quality of life (HRQoL) in a sample of Spanish adolescents. A total sample of 634 adolescents was included (mean age: 13.96 ± 1.54 years; 56.9% girls). The Mediterranean Diet Quality Index in children and adolescents (KIDMED) and the KIDSCREEN-10 were used to assess adherence to the MedDiet and its components and HRQoL, respectively. Linear regression was applied to estimate the association between overall adherence to the MedDiet and HRQoL. Cluster analysis was used to establish subgroups according to different patterns of MedDiet component consumption. Higher overall adherence to the MedDiet was significantly associated with greater HRQoL (unstandardized beta coefficient [β] = 0.329; 95% CI: 0.108, 0.550; p = 0.004), even after adjustment for sociodemographic, physical and lifestyle covariates (β = 0.228; 95% CI: 0.007, 0.449; p = 0.043). When different clusters were established according to similar features of MedDiet component consumption, the cluster with a higher percentage of individuals who skipped breakfast had significantly lower scores on the HRQoL scale (p < 0.05)  Conclusions: Our findings highlight the relevance of considering the specific patterns of food group consumption and MedDiet-related behaviors and not just the overall measure of MedDiet adherence for promoting HRQoL in adolescents. What is Known: • Previous studies have shown that some lifestyle behaviors, such as dietary habits, could be associated with health-related quality of life. • According to our results, higher adherence to the Mediterranean diet pattern was associated with greater health-related quality of life in adolescents. What is New: • Skipping breakfast seems to have a crucial role in health-related quality of life among adolescents. • These results could lead to the development of more specific dietary strategies for increasing health-related quality of life in adolescents.

Dietary habits of patients with coronary artery disease in a tertiary-care hospital of Bangladesh: a case-controlled study

BACKGROUND AND OBJECTIVES

Globally, coronary artery disease (CAD) remains one of the leading causes of death, both in developed and less economically developed countries (LEDC) including Bangladesh. Diet plays a key role in the pathogenesis processes of atherosclerosis and coronary artery disease (CAD). The purpose of this study was to assess the dietary habit of heart disease cases that had CAD against matched controls.

METHODOLOGY

Complying Helsinki ethical norms, with written consent, this case-control study was performed among 210 subjects: 105 CAD-hospitalized patients (selected from Lab Aid Cardiac and Specialized Hospitals) and 105 healthy subjects from local urban communities having their body mass index (BMI: ranging between ≥18.5 and 27 socio-demographic status, detailed-dietary patterns and blood pressure levels were recorded, anthropometric indices measured, and serum biochemistry (complete lipid profile) tested/analyzed for both the cases and controls. All visually re-checked data were analyzed using appropriate statistical tools (t test/conditional-logistic regressions) on SPS/Windows V.21.0.

RESULT

Almost half (45%) CAD patients had hypertriglyceridemia and higher levels of low-density lipoprotein, significantly higher BMA (p=0.001), waist circumference, and waist to hip ratio in male patients (p=0.005 and p=0.020, respectively) than their peer controls. Serum lipid profiles, sugar concentrations, and blood pressure levels of CAD patients revealed higher levels than clinically defined cut-off values as established risk factors for CAD. Odds ratios (CI 95%) as risk factors for consuming junk food {OR=5.49 (2.25-13.38)}, chicken {OR=4.54 (1.89-10.9) was the most, followed by beef {OR=2.68 (1.19-4.98)}, eggs {OR=2.38 (1.14-10.92)}, fish {OR=2.81 (1.31-6.04)}, and vegetables {0R=.968 (0.510-1.839)}. However, fat-free milk, ghee/butter oil, curd/yogurt, and fruits had lower ORs revealing no or less risks for CAD.

CONCLUSION

Food habits of CAD patients (with higher BMI level and biochemical indicators of the blood) statistically revealed that consuming junk food, meat, and eggs being riskier, fruits, fat-free milk, yogurt, and vegetable remains have protective effects on CAD.

Reproducibility and Validity of A Posteriori Dietary Patterns: A Systematic Review

The effective use of dietary patterns (DPs) remains limited. There is a need to assess their consistency over multiple administrations of the same dietary source, different dietary sources, or across different studies. Similarly, their generalizability should be based on a previous assessment of DP construct validity. However, to date, no systematic reviews of reproducibility and validity of a posteriori DPs have been carried out. In addition, several methodological questions related to their identification are still open and prevent a fair comparison of epidemiological results on DPs and disease. A systematic review of the literature on the PubMed database was conducted. We identified 218 articles, 64 of which met the inclusion criteria. Of these, the 38 articles dealing with reproducibility and relative and construct validity of DPs were included. These articles (published in 1999-2017, 53% from 2010 onwards) were based on observational studies conducted worldwide. The 14 articles that assessed DP reproducibility across different statistical solutions examined different research questions. Included were: the number of food groups or subjects; input variable format (as well as adjustment for energy intake); algorithms and the number of DPs to retain in cluster analysis; rotation method; and score calculation in factor analysis. However, we identified at most 3 articles per research question on DP reproducibility across statistical solutions. From another 15 articles, reproducibility of DPs over shorter (≤1 y) time periods was generally good and higher than DP relative validity (as measured across different dietary sources). Confirmatory factor analysis was used in 15 of the included articles. It provided reassuring results in identifying valid dietary constructs characterizing the populations under consideration. Based on the available evidence, only suggestive conclusions can be derived on reproducibility across different statistical solutions. Nevertheless, most identified DPs showed good reproducibility, fair relative validity, and good construct validity.

Strategies to Address Misestimation of Energy Intake Based on Self-Report Dietary Consumption in Examining Associations Between Dietary Patterns and Cancer Risk

The objective of this study was to determine the influence of strategies of handling misestimation of energy intake (EI) on observed associations between dietary patterns and cancer risk. Data from Alberta's Tomorrow Project participants (n = 9,847 men and 16,241 women) were linked to the Alberta Cancer Registry. The revised-Goldberg method was used to characterize EI misestimation. Four strategies assessed the influence of EI misestimation: Retaining individuals with EI misestimation in the cluster analysis (Inclusion), excluding before (ExBefore) or after cluster analysis (ExAfter), or reassigning into ExBefore clusters using the nearest neighbor method (InclusionNN). Misestimation of EI affected approximately 50% of participants. Cluster analysis identified three patterns: Healthy, Meats/Pizza and Sweets/Dairy. Cox proportional hazard regression models assessed associations between the risk of cancer and dietary patterns. Among men, no significant associations (based on an often-used threshold of p < 0.05) between dietary patterns and cancer risk were observed. In women, significant associations were observed between the Sweets/Dairy and Meats/Pizza patterns and all cancer risk in the ExBefore (HR (95% CI): 1.28 (1.04-1.58)) and InclusionNN (HR (95% CI): 1.14 (1.00-1.30)), respectively. Thus, strategies to address misestimation of EI can influence associations between dietary patterns and disease outcomes. Identifying optimal approaches for addressing EI misestimation, for example, by leveraging biomarker-based studies could improve our ability to characterize diet-disease associations.

1H NMR-based metabolomics reveals the effect of maternal habitual dietary patterns on human amniotic fluid profile

Maternal diet may influence offspring’s health, even within well-nourished populations. Amniotic fluid (AF) provides a rational compartment for studies on fetal metabolism. Evidence in animal models indicates that maternal diet affects AF metabolic profile; however, data from human studies are scarce. Therefore, we have explored whether AF content may be influenced by maternal diet, using a validated food-frequency questionnaire and implementing NMR-based metabolomics. Sixty-five AF specimens, from women undergoing second-trimester amniocentesis for prenatal diagnosis, were analysed. Complementary, maternal serum and urine samples were profiled. Hierarchical cluster analysis identified 2 dietary patterns, cluster 1 (C1, n = 33) and cluster 2 (C2, n = 32). C1 was characterized by significantly higher percentages of energy derived from refined cereals, yellow cheese, red meat, poultry, and “ready-to-eat” foods, while C2 by higher (P < 0.05) whole cereals, vegetables, fruits, legumes, and nuts. ¹H NMR spectra allowed the identification of metabolites associated with these dietary patterns; glucose, alanine, tyrosine, valine, citrate, cis-acotinate, and formate were the key discriminatory metabolites elevated in C1 AF specimens. This is the first evidence to suggest that the composition of AF is influenced by maternal habitual dietary patterns. Our results highlight the need to broaden the knowledge on the importance of maternal nutrition during pregnancy.

Multivariate classification of the geographic origin of Chinese cabbage using an electronic nose-mass spectrometry

An electronic nose-mass spectrometry (EN-MS) that profiles volatile compounds is a candidate device for identifying the geographic origin of cultivation of agricultural products when an adequate algorithm is derived. The objectives of this study were to apply two types of multivariate analysis, discriminant function analysis (DFA) and principal component analysis (PCA), to the volatile compounds detected by an EN-MS for the geographic classification of Chinese cabbage cultivated in Korea (42 samples) or in China (29 samples). DFA showed that Chinese cabbage from Korea were completely separable from those originating in China with 12 volatile compounds among the 151 detected. PCA revealed that Chinese cabbage data fell into two completely separable origins of Korea and China. This is the first study involving EN-MS data of volatile compounds with multivariate statistics to discriminate the geographical origin of Chinese cabbage, with further applications for other agricultural products.

Dietary Patterns Characterized by High Meat Consumption Are Associated with Other Unhealthy Life Styles and Depression Symptoms

OBJECTIVE

We aimed to identify dietary patterns (DPs) of Portuguese adults, to assess their socioeconomic, demographic, lifestyle determinants, and to identify their impact on health.

DESIGN

EpiDoC 2 study included 10,153 Portuguese adults from the EpiDoC Cohort, a population-based study. In this study, trained research assistants using computer-assisted telephone interview collected socioeconomic, demographic, dietary, lifestyles, and health information from March 2013 to July 2015. Cluster analysis was performed, based on questions regarding the number of meals, weekly frequency of soup consumption, vegetables, fruit, meat, fish, dairy products, and daily water intake. Factors associated with DP were identified through logistic regression models.

RESULTS

Two DPs were identified: the "meat dietary pattern" and the "fruit & vegetables dietary pattern." After multivariable adjustment, women (OR = 0.52; p < 0.001), older adults (OR = 0.97; p < 0.001), and individuals with more years of education (OR = 0.96; p = 0.025) were less likely to adopt the "meat dietary pattern," while individuals in a situation of job insecurity/unemployment (OR = 1.49; p = 0.013), Azores island residents (OR = 1.40; p = 0.026), current smoking (OR = 1.58; p = 0.001), daily alcohol intake (OR = 1.46; p = 0.023), and physically inactive (OR = 1.86; p < 0.001) were positively and significantly associated with "meat dietary pattern." Moreover, individuals with depression symptoms (OR = 1.50; p = 0.018) and the ones who did lower number of medical appointments in the previous year (OR = 0.98; p = 0.025) were less likely to report this DP.

CONCLUSION

Our results suggest that unhealthy DPs (meat DP) are part of a lifestyle behavior that includes physical inactivity, smoking habits, and alcohol consumption. Moreover, depression symptoms are also associated with unhealthy DPs.

Dietary patterns in India: a systematic review

Dietary patterns analysis is an emerging area of research. Identifying distinct patterns within a large dietary survey can give a more accurate representation of what people are eating. Furthermore, it allows researchers to analyse relationships between non-communicable diseases (NCD) and complete diets rather than individual food items or nutrients. However, few such studies have been conducted in developing countries including India, where the population has a high burden of diabetes and CVD. We undertook a systematic review of published and grey literature exploring dietary patterns and relationships with diet-related NCD in India. We identified eight studies, including eleven separate models of dietary patterns. Most dietary patterns were vegetarian with a predominance of fruit, vegetables and pulses, as well as cereals; dietary patterns based on high-fat, high-sugar foods and more meat were also identified. There was large variability between regions in dietary patterns, and there was some evidence of change in diets over time, although no evidence of different diets by sex or age was found. Consumers of high-fat dietary patterns were more likely to have greater BMI, and a dietary pattern high in sweets and snacks was associated with greater risk of diabetes compared with a traditional diet high in rice and pulses, but other relationships with NCD risk factors were less clear. This review shows that dietary pattern analyses can be highly valuable in assessing variability in national diets and diet-disease relationships. However, to date, most studies in India are limited by data and methodological shortcomings.

The effect of under-reporting of energy intake on dietary patterns and on the associations between dietary patterns and self-reported chronic disease in women aged 50–69 years

The aim of this cross-sectional study was to investigate whether under-reporting of energy intake affects derived dietary patterns and the association between dietary patterns and self-reported chronic disease. Diets of 6204 women aged 50–69 years participating in the Norwegian Breast Cancer Screening Program were assessed using a 253-item FFQ. We identified dietary patterns using principal component analysis. According to the revised Goldberg cut-off method, women with a ratio of reported energy intake:estimated BMR<1·10 were classified as low energy reporters (n 1133, 18 %). We examined the associations between dietary patterns and self-reported chronic diseases by log-binomial regression, and the results are presented as prevalence ratios (PR) and CI. ‘Prudent’, ‘Western’ and ‘Continental’ dietary patterns were identified among all reporters and plausible reporters. The PR expressing the associations between the ‘Western’ and ‘Prudent’ dietary pattern scores and self-reported chronic diseases were consistently highest among plausible reporters except for joint/muscle/skeletal disorders. The largest difference in PR among plausible v. all reporters was found for the association between the ‘Prudent’ pattern and diabetes (PR for highest v. lowest tertile: PRall reporters 2·16; 95 % CI 1·50, 3·13; Ptrend<0·001; PRplausible reporters 2·86; 95 % CI 1·81, 4·51; Ptrend<0·001). In conclusion, our results suggest that under-reporting can result in systematic error that can affect the association between dietary pattern and disease. In studies of dietary patterns, investigators ought to consider reporting effect estimates both for all individuals and for plausible reporters.

Dietary patterns in Swedish adults; results from a national dietary survey

Dietary patterns derived by statistical procedures is a way to identify overall dietary habits in specific populations. The aim of this study was to identify and characterise dietary patterns in Swedish adults using data from the national dietary survey Riksmaten adults 2010-11 (952 women, 788 men). Principal component analyses were used and two patterns were identified in both sexes: a healthy pattern loading positively on vegetables, fruits, fish and seafood, and vegetable oils, and negatively on refined bread and fast food, and a Swedish traditional pattern loading positively on potatoes, meat and processed meat, full-fat milk products, sweet bakery products, sweet condiments and margarine. In addition, a light-meal pattern was identified in women with positive loadings on fibre-rich bread, cheese, rice, pasta and food grain dishes, substitute products for meat and dairy products, candies and tea. The healthy pattern was positively correlated to dietary fibre (r 0·51-0·58) and n-3 (r 0·25-0·31) (all P<0·0001), and had a higher nutrient density of folate, vitamin D and Se. The Swedish traditional and the light-meal pattern were positively correlated to added sugar (r 0·20-0·25) and the Swedish traditional also to SFA (r 0·13-0·21) (all P<0·0001); both patterns were in general negatively correlated to micronutrients. Dietary pattern scores were associated with, for example, age, physical activity, education and income. In conclusion, we identified three major dietary patterns among Swedish adults. The patterns can be further used for examining the association between whole diet and health outcomes.

Effect of energy under-reporting on secular trends of dietary patterns in a mediterranean population

BACKGROUND

Diet is an important factor in the prevention of chronic diseases. Analysis of secular trends of dietary patterns can be biased by energy under-reporting. Therefore, the objective of the present study was to analyse the impact of energy under-reporting on dietary patterns and secular trends in dietary patterns defined by cluster analysis.

DESIGN AND METHODS

Two cross-sectional population-based surveys were conducted in Spain, in 2000 and 2005, with 3058 and 6352 participants, respectively, aged 25 to 74 years. Validated questionnaire was used to collect dietary data. Cluster analysis was run separately for all participants, plausible energy reporters (PER), and energy under-reporters (EUR) to define dietary patterns.

RESULTS

Three clusters, "healthy", "mixed" and "western", were identified for both surveys. The "mixed" cluster was the predominant cluster in both surveys. Excluding EUR reduced the proportion of the "mixed" cluster up to 6.40% in the 2000 survey; this caused secular trend increase in the prevalence of the "mixed" pattern. Cross-classification analysis of all participants and PER' data showed substantial agreement in cluster assignments: 68.7% in 2000 and 84.4% in 2005. Excluding EUR did not cause meaningful (≥ 15%) changes in the "healthy" pattern. It provoked changes in consumption of some food groups in the "mixed" and "western" patterns: mainly decreases of unhealthy foods within the 2000 and increases of unhealthy foods within the 2005 surveys. Secular trend effects of EUR were similar to those within the 2005 survey. Excluding EUR reversed the direction of secular trends in consumption of several food groups in PER in the "mixed" and "western" patterns.

CONCLUSIONS

EUR affected distribution of participants between dietary patterns within and between surveys, secular trends in food group consumption and amount of food consumed in all, but not in the "healthy" pattern. Our findings emphasize threats from energy under-reporting in dietary data analysis.

Dietary Patterns as Predictors of Body Fat and BMI in Women: A Factor Analytic Study

Purpose.

To identify independent patterns of diet using factor analysis to determine the extent to which dietary patterns account for differences in body fat percentage (BF%) and body mass index (BMI). Also, to ascertain the extent to which the associations are influenced by age, education, menopause, energy intake, and physical activity.

Design.

Study design was cross-sectional.

Setting.

Study setting was approximately 20 cities in the Mountain West.

Subjects.

The study included 281 apparently healthy female nonsmokers.

Measures.

Diet was assessed using 7-day weighed food records, and foods were categorized using the American Diabetes and American Dietetic Associations Exchange Lists and expressed as servings per 1000 kcal. BF% was measured using the Bod Pod, and physical activity was estimated using accelerometers worn for 1 week.

Analysis.

We used factor analysis, general linear models, and partial correlations.

Results.

Three dietary patterns were identified: (1) Prudent Pattern, (2) Low-fat Milk, and (3) Meat. Higher consumption of the Prudent Pattern corresponded with significantly lower BF% (F = 8.5, p = .0038) and BMI (F = 4.4, p = .0363). The Low-fat Milk pattern was inversely related to BF% (F= 5.4, p = .0207) and BMI (F= 9.5, p = .0023). Higher intake of the Meat pattern was related to higher levels of BF% (F= 4.5, p= .0346) and BMI (F= 4.2, p = .0418).

Conclusion.

These findings support an association between dietary patterns and body composition. Dietary patterns reflect the complex interrelationships inherent in day-to-day eating and are strongly related to differences in BF% and BMI in women.

Dietary patterns and whole grain cereals in the Scandinavian countries – differences and similarities. The HELGA project

Objective

To identify dietary patterns with whole grains as a main focus to see if there is a similar whole grain pattern in the three Scandinavian countries; Denmark, Sweden and Norway. Another objective is to see if items suggested for a Nordic Food Index will form a typical Nordic pattern when using factor analysis.

Setting

The HELGA study population is based on samples of existing cohorts: the Norwegian Women and Cancer Study, the Swedish Västerbotten cohort and the Danish Diet, Cancer and Health study. The HELGA study aims to generate knowledge about the health effects of whole grain foods.

Subjects

The study included a total of 119 913 participants.

Design

The associations among food variables from FFQ were investigated by principal component analysis. Only food groups common for all three cohorts were included. High factor loading of a food item shows high correlation of the item to the specific diet pattern.

Results

The main whole grain for Denmark and Sweden was rye, while Norway had highest consumption of wheat. Three similar patterns were found: a cereal pattern, a meat pattern and a bread pattern. However, even if the patterns look similar, the food items belonging to the patterns differ between countries.

Conclusions

High loadings on breakfast cereals and whole grain oat were common in the cereal patterns for all three countries. Thus, the cereal pattern may be considered a common Scandinavian whole grain pattern. Food items belonging to a Nordic Food Index were distributed between different patterns.

Dietary patterns within a population are more reproducible than those of individuals

Insight into the stability of dietary behavior over time is important, because only a single measurement of diet is often available to study the association between eating behavior and the occurrence of chronic diseases many years after baseline data collection. Little is known about changes in dietary patterns over time. The current study examined the (internal) stability and reproducibility of dietary patterns and the transition of individuals between patterns over time from 3 surveys within one study population by using cluster analysis. The dietary intake of participants in the Doetinchem Cohort Study in 6113, 4916, and 4520 adults in 1993-1997, 1998-2002, and 2003-2007, respectively, was measured using a validated food-frequency questionnaire. Stability and reproducibility of dietary patterns were studied by examining the optimal number of clusters per survey by comparing the contribution of food groups to total energy intake within the clusters over time and by studying transitions of individuals between clusters over time. A low-fiber bread pattern and a high-fiber bread pattern were identified in all 3 surveys. Over time, dietary patterns were comparable in terms of foods contributing most to total energy intake, suggesting good reproducibility. Nevertheless, only 41.8% of the participants were consistently assigned to the same dietary pattern for all 3 surveys. This implies that, over time, similar dietary patterns were found at the group level, but that ignoring individual transitions between dietary patterns during follow-up may lead to misclassification of a large proportion of the study population.

Exploring dietary patterns, obesity and sources of bias: the Västerbotten Intervention Programme (VIP)

OBJECTIVE

Dietary patterns capture the overall diet and thereby provide information on how nutrients are consumed in combinations, and have been suggested to be a better method than studying single nutrients. The present study explored the relationship between dietary patterns at baseline and incidence of obesity at 10-year follow-up in women.

DESIGN

A longitudinal study using baseline measurements from 1992-1996, including food intake, medication, heredity, socio-economic status, lifestyle and measured body composition, and follow-up data collected in 2002-2006 including measured body composition.

SETTING

Data from the Västerbotten Intervention Programme (VIP) in Sweden.

SUBJECTS

A total of 6545 initially non-obese women aged 30-50 years.

RESULTS

Among women reporting plausible energy intakes, the 'Fruit and vegetables cluster' predicted the highest incidence of obesity (OR = 1·76, 95 % CI 1·11, 2·76; P = 0·015) compared with women in the other food pattern groups combined. When adjusting for metabolic factors and BMI at baseline, the risk for obesity in the 'Fruit and vegetables cluster' was attenuated to non-significance. In contrast, high intake of fruit per se was associated with a decreased risk of developing obesity (OR = 0·69, 95 % CI 0·51, 0·91; P = 0·010).

CONCLUSIONS

Dietary pattern groups identified by cluster analysis are likely to reflect characteristics in addition to diet, including lifestyle, previous and current health status and risk factors for future disease, whereas intake of fruit per se was a stable indicator and less affected by baseline characteristics. These results underscore the need for complementary methods in understanding diet-disease relationships.

Baseline dietary patterns are a significant consideration in correcting dietary exposure for weight loss

BACKGROUND/OBJECTIVES

Dietary pattern studies are traditionally the domain of epidemiological research. From a clinical perspective, there is a need to explore the effects of changing food and dietary patterns of individuals. The aim was to identify patterns of food choice in the context of a clinical weight loss trial. Cluster analysis based on reported serves of food groups revealed dietary patterns informative for the clinical setting.

SUBJECTS/METHODS

Cluster analysis was conducted using diet history data from two clinical trials at baseline, and outcomes at 3 months were reviewed based on these clusters (n=231). The cluster solution was analysed using defined food groups in serves and with respect to clinical parameters and requirements for selected nutrients.

RESULTS

Two distinct dietary patterns were identified from the reported baseline dietary intakes. Subjects in Cluster 1 reported food patterns characterised by higher intakes of low-fat dairy and unsaturated oils and margarine and were generally more closely aligned to food choices encouraged in national dietary guidelines. Subjects in Cluster 2 reported a dietary pattern characterised by non-core foods and drinks, higher- and medium-fat dairy foods, fatty meats and alcohol. At 3 months, Cluster 2 subjects reported greater reductions in energy intake (-5317 kJ; P<0.001) and greater weight loss (-5.6 kg; P<0.05) compared with Cluster 1.

CONCLUSIONS

Overweight subjects with reported dietary patterns similar to dietary guidelines at baseline may have more difficulty in reducing energy intake than those with poor dietary patterns. Correcting exposure to non-core foods and drinks was key to successful weight loss.

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.

Food patterns, inflammation markers and incidence of cardiovascular disease: the Malmö Diet and Cancer study

OBJECTIVES

To examine the associations between food patterns constructed using cluster analysis and markers of systemic and vascular inflammation, and incident cardiovascular disease (CVD) after 13 years of follow-up.

DESIGN

Population-based, prospective cohort study.

SETTING AND SUBJECTS

Cluster analysis identified six food patterns from 43 food group variables among 4999 subjects, aged 45-68 years, who participated in the Malmö Diet and Cancer cardiovascular programme between 1991 and 1994. Lipoprotein-associated phospholipase A(2) (Lp-PLA(2) ), C-reactive protein concentration and white blood cell (WBC) count were measured using blood samples at baseline. Incidence of CVD (coronary events and ischaemic stroke) was monitored over 13 years of follow-up.

RESULTS

The fibre-rich bread pattern was associated with favourable effects on WBC count in women, and the low-fat and high-fibre pattern with favourable effects on Lp-PLA(2) mass in women, and on Lp-PLA(2) activity in men. However, the milk fat and sweets and cakes patterns were both associated with adverse effects; the former on WBC count in women and on Lp-PLA(2) mass in men, and the latter on WBC count and Lp-PLA(2) mass in women. The milk fat and sweets and cakes patterns were associated with increased CVD risk in women.

CONCLUSIONS

The results of this study support the present Nordic dietary recommendations indicating that diets rich in high-fibre, low-fat and low-sugar foods are favourably associated with markers of inflammation and, potentially, with CVD risk.

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.

Consumer segmentation based on the level and structure of fruit and vegetable intake: an empirical evidence for US adults from the National Health and Nutrition Examination Survey (NHANES) 2005-2006

OBJECTIVE

To identify consumption patterns of fruit and vegetables within a representative sample of US adults with a focus on degree of produce processing and to explore sociodemographic, lifestyle and nutritional profiles associated with these patterns.

DESIGN

Cross-sectional analysis. Fruit and vegetable (F&V) consumption data were collected using two non-consecutive 24 h recalls. For the purpose of the study, F&V intakes were aggregated into seven subgroups indicating degree of processing, which afterwards were used as inputs into cluster analysis.

SETTING

The 2005-2006 National Health and Nutrition Examination Survey.

SUBJECTS

The sample consisted of 2444 adults aged 20-59 years.

RESULTS

Total average F&V intake of the adults was below the recommended level. Thereby, 20 % of the respondents consumed fruit only in the form of juice. Three F&V consumption patterns were identified: 'low-intake F&V consumers' (74 % of respondents), 'consumers of healthier F&V options' (13 %) and 'intensive fruit juice consumers' (13 %). These groups differed markedly in terms of their sociodemographic, lifestyle and health characteristics, such as gender, age, race/ethnicity, education, smoking, weight status, etc. Differences in nutrient profiles were also found, with the 'consumers of healthier F&V options' showing better nutritional quality compared with other clusters.

CONCLUSIONS

Only a small share of US adults combines high F&V intakes with healthier F&V options that lead to a better nutritional profile. This raises discussion about a need to deliver more specific F&V promotion messages, including advice on healthier preparation methods, especially for the specific population groups.

Food intake patterns and body mass index in older adults: a review of the epidemiological evidence

The relationship between food intake patterns and obesity remains unclear. The objective of the present review was to evaluate the current body of literature on food intake patterns of older adults and their associations with weight status, including obesity and waist circumference. Eleven observational studies were identified and reviewed. Diets characterized by more favorable dietary scores or indices were generally inversely related to body mass index. Results from data-driven approaches were inconsistent. Findings from this literature review suggest that there is no clear relationship between food intake patterns and body mass index or waist circumference in older adults. Limitations, including heterogeneity of food intake patterns and study populations, hinder the ability to make clear comparisons. Continued efforts to elucidate the relationship between food intake patterns and weight status indicators in older adults, including longitudinal analyses and use of novel statistical approaches for food intake pattern identification, are warranted.

Mis-reporting, previous health status and health status of family may seriously bias the association between food patterns and disease

Background

Food pattern analyses are popular tools in the study of associations between diet and health. However, there is a need for further evaluation of this methodology. The aim of the present cross-sectional study was to evaluate the relationship between food pattern groups (FPG) and existing health, and to identify factors influencing this relationship.

Methods

The inhabitants of Västerbotten County in northern Sweden are invited to health check-ups when they turn 30, 40, 50, and 60 years of age. The present study includes data collected from almost 60,000 individuals between 1992 and 2005. Associations between FPG (established using K-means cluster analyses) and health were analyzed separately in men and women.

Results

The health status of the participants and their close family and reporting accuracy differed significantly between men and women and among FPG. Crude regression analyses, with the high fat FPG as reference, showed increased risks for several health outcomes for all other FPGs in both sexes. However, when limiting analysis to individuals without previous ill-health and with adequate energy intake reports, most of the risks instead showed a trend towards protective effects.

Conclusions

Food pattern classifications reflect both eating habits and other own and family health related factors, a finding important to remember and to adjust for before singling out the diet as a primary cause for present and future health problems. Appropriate exclusions are suggested to avoid biases and attenuated associations in nutrition epidemiology.

Analysis of dietary patterns in epidemiological researchThis 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?

Dietary patterns have been used to summarize diet consumption and to evaluate how diet is associated with diseases in epidemiological research. However, there are many issues surrounding both the use and interpretation of dietary patterns. These issues include how to collect, summarize, and create dietary patterns, as well as how to interpret the results. Because labels are given arbitrarily to dietary patterns to help characterize the pattern in a meaningful way, it is often not clear from the literature as to the consistency of results among studies. Additionally, the utilization of dietary patterns as a tool for public health messages is a topic that is unresolved. These issues are discussed in this paper.

More distinct food intake patterns among women than men in northern Sweden: a population-based survey

BACKGROUND

The need to promote a healthy diet to curb the current obesity epidemic has today been recognized by most countries. A prerequisite for planning and evaluating interventions on dietary intake is the existence of valid information on long-term average dietary intake in a population. Few large, population-based studies of dietary intake have been carried out in Sweden. The largest to date is the Västerbotten Intervention Program (VIP), which was initiated in 1985, with data collection still ongoing. This paper reports on the first comprehensive analyses of the dietary data and presents dietary intake patterns among over 60,000 women and men in northern Sweden during 1992-2005.

METHODS

Between 1992 and 2005, 71,367 inhabitants in Västerbotten county aged 30, 40, 50, and 60 years visited their local health care center as part of the VIP. Participants of VIP filled in an 84- or 64-item food frequency questionnaire (FFQ) and provided sociodemographic information. Complete and realistic information on consumption frequency was provided by 62,531 individuals. Food intake patterns were analyzed using K-means cluster analyses.

RESULTS

The mean daily energy intake was 6,83 (+/- 1,77) MJ among women and 8,71 (+/- 2,26) MJ among men. More than half of both women and men were classified as Low Energy Reporters (defined as individuals reporting a food intake level below the lower 95% confidence interval limit of the physical activity level). Larger variation in frequency of daily intake was seen among women than among men for most food groups. Among women, four dietary clusters were identified, labeled "Fruit and vegetables", "High fat", "Coffee and sandwich", and "Tea and ice cream". Among men, three dietary clusters were identified, labeled "Fruit and vegetables", "High fat", and "Tea, soda and cookies".

CONCLUSION

More distinct food intake patterns were seen among women than men in this study in northern Sweden. Due to large proportions of Low Energy Reporters, our results on dietary intake may not be suitable for comparisons with recommended intake levels. However, the results on food intake patterns should still be valid and useful as a basis for targeting interventions to groups most in need.

Mediterranean diet is associated with reduced asthma and rhinitis in Mexican children

BACKGROUND

Diet during pregnancy and childhood has been suggested to play an important role in children's asthma risk. We assessed whether the adherence to a Mediterranean dietary pattern, for children in the last 12 months and their mothers during pregnancy, was associated with both childhood asthma and allergic rhinitis.

METHODS

A cross-sectional study was conducted in 2004 using a random sample of 1476 children (6- to 7-year old) from the Mexicali region, Mexico. Dietary data of children's intake in the last 12 months and their mothers' intake during pregnancy was collected, through a parental food frequency questionnaire. A Mediterranean diet score was computed [Trichopoulou et al., N Engl J Med 348 (2003), 2599]. Data on seven asthma and rhinitis-related outcomes were obtained from the International Study of Asthma and Allergies in Childhood questionnaire.

RESULTS

Adherence to a Mediterranean dietary pattern was inversely associated with asthma ever (OR = 0.60, 95% CI = 0.40-0.91), wheezing ever (0.64, 0.47-0.87), rhinitis ever (0.41, 0.22-0.77), sneezing ever (0.79, 0.59-1.07), current sneezing (0.71, 0.52-0.96) and current itchy-watery eyes (0.63, 0.42-0.95). No associations were found using the mothers' pregnancy diet score, except for current sneezing (0.71, 0.53-0.97).

CONCLUSIONS

Our findings suggest a protective effect of following a healthy dietary pattern on asthma and allergic rhinitis in Mexican children.

Associação dos padrões alimentares com obesidade geral e abdominal em mulheres residentes no Sul do Brasil

Com objetivo de estudar a associação de padrões alimentares com obesidade, realizou-se estudo transversal de base populacional com amostra representativa de 1.026 mulheres (20 a 60 anos) em São Leopoldo, Rio Grande do Sul, Brasil. A obesidade geral foi avaliada pela utilização de índice de massa corporal (IMC > 30kg/m²) e a adiposidade abdominal, circunferência da cintura (CC> 88cm). Os padrões alimentares foram identificados por análise fatorial. Para análise multivariada, foi utilizada regressão de Poisson. Entre o total de mulheres, 18% (IC95%: 15,66-20,53) tinham obesidade geral e 23,3% (IC95%: 20,72-26,06) abdominal. Após controle para fatores de confusão, o baixo consumo do PA-frutas associou-se positivamente com o IMC (RP = 2,18; IC95%: 1,35-3,53; p = 0,001). Já o baixo consumo do PA-vegetais apresentou efeito protetor para o aumento nos níveis de IMC (RP = 0,64; IC95%: 0,47-0,86; p = 0,004) e o do PA-nozes/oleaginosas para o aumento na medida da CC (RP = 0,93; IC95%: 0,89-0,98; p = 0,008). O estudo aponta para a complexidade envolvida na relação entre padrões alimentares e obesidade e a necessidade de novos estudos, objetivando o melhor entendimento do tema.

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.

Dietary patterns and 15-y risks of major coronary events, diabetes, and mortality

BACKGROUND

Few studies have examined the long-term effect of habitual diet on risks of incident diabetes, coronary heart disease, and mortality.

OBJECTIVE

We analyzed the prospective relation of dietary patterns with incident chronic disease and mortality during 15 y of follow-up in the Whitehall II study.

DESIGN

We conducted a prospective analysis (106,633 person-years at risk) among men and women (n = 7731) with a mean age of 50 y at the time of dietary assessment (127-item food-frequency questionnaire). Coronary death or nonfatal myocardial infarction and incident diabetes were verified by record tracing and oral-glucose-tolerance tests.

RESULTS

Cluster analysis identified 4 dietary patterns at baseline. The patterns were termed unhealthy (white bread, processed meat, fries, and full-cream milk; n = 2665), sweet (white bread, biscuits, cakes, processed meat, and high-fat dairy products; n = 1042), Mediterranean-like (fruit, vegetables, rice, pasta, and wine; n = 1361), and healthy (fruit, vegetables, whole-meal bread, low-fat dairy, and little alcohol; n = 2663). Compared with the unhealthy pattern, the healthy pattern reduced the risk of coronary death or nonfatal myocardial infarction and diabetes; hazard ratios (95% CI) were 0.71 (0.51, 0.98) and 0.74 (0.58, 0.94), respectively, after adjustment for age, sex, ethnicity, dietary energy misreporting, social position, smoking status, and leisure-time physical activity. Dietary pattern was not associated with all-cause mortality. Residual confounding by socioeconomic factors was unlikely to account for the observed dietary effects.

CONCLUSIONS

The healthy eating pattern reduced risks of diabetes and major coronary events. Such dietary patterns offer considerable health benefits to individuals and contribute to public health.

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'.

The relationship among cardiovascular risk factors, diet patterns, alcohol consumption, and ethnicity among women aged 50 years and older

BACKGROUND

Cardiovascular disease (CVD) is the leading cause of death among women of all races and ethnicities. The risk of developing the disease is greater in postmenopausal women.

OBJECTIVE

The purpose of this study was to use cluster analysis to examine diet patterns and to examine the association between diet patterns and the presence of major cardiovascular disease risk factors.

DESIGN

Data from the cross-sectional National Health and Nutrition Examination Survey (NHANES) 2001-2002 were used.

SUBJECTS/SETTING

Women aged 50 years and older were included (n=1,313).

MAIN OUTCOME MEASURES

The following major CVD risk factors were examined: being overweight or obese (body mass index >24.9), having elevated systolic blood pressure (>120 mm Hg), and having low levels of high-density lipoprotein cholesterol (<50 mg/dL [<1.30 mmol/L]). Dietary patterns were derived by cluster analysis using data from a 24-hour dietary recall.

STATISTICAL ANALYSES PERFORMED

Odds Ratios (ORs) and 95% confidence intervals (CIs) were calculated using logistic regression to determine the probability of having a risk factor according to diet pattern while accounting for race/ethnicity, physical activity, age, and smoking.

RESULTS

Cluster analysis generated six nonoverlapping diet patterns labeled: Pasta and Yellow Vegetables; Sweets; Beef, Starches, Fruits, and Milk; Frozen Meals, Burritos, and Pizza; Meat Dishes; and Soft Drinks and Poultry. The majority of the women were grouped in the Sweets diet pattern. Factors associated with adequate levels of high-density lipoprotein cholesterol included being non-Hispanic African American (OR 0.59, 95% CI 0.44 to 0.81; P<0.0001), alcohol consumption (OR 0.76, 95% CI 0.69 to 0.84; P<0.0001), and being assigned to the Sweets diet pattern (OR 0.27, 95% CI 0.14 to 0.50; P<0.0001) or Meat dishes diet pattern (OR 0.94, 95% CI 0.54 to 1.65; P<0.0075). The Sweets pattern was also associated with having normal systolic blood pressure levels (OR 0.51, 95% CI 0.34 to 0.76; P<0.0001). Individuals grouped in the Beef, Starches, and Milk diet pattern were more likely to have an adequate body mass index (OR 0.42, 95% CI 0.23 to 0.77; P<0.0032).

CONCLUSIONS

Significant associations between dietary patterns and major CVD risk factors were observed. Food and nutrition professionals can use this information to assess unhealthful food choices observed in the dietary patterns to guide nutrition recommendations and help reduce the incidence of CVD risk factors. Future research should aim to evaluate dietary intake via complementary methods (ie, dietary patterns and nutrient assessment) to better understand diet-disease relationships.

Clusters of lifestyle behaviors: results from the Dutch SMILE study

OBJECTIVE

This study aimed to identify differences and similarities in health behavior clusters for respondents with different educational backgrounds.

METHODS

A total of 9449 respondents from the 2002 wave of the Dutch SMILE cohort study participated. Latent class analyses were used to identify clusters of people based on their adherence to Dutch recommendations for five important preventive health behaviors: non-smoking, alcohol use, fruit consumption, vegetable consumption and physical exercise.

RESULTS

The distribution of these groups of behaviors resulted in three clusters of people: a healthy, an unhealthy and poor nutrition cluster. This pattern was replicated in groups with low, moderate and high educational background. The high educational group scored much better on all health behaviors, whereas the lowest educational group scored the worst on the health behaviors.

CONCLUSION

The same three patterns of health behavior can be found in different educational groups (high, moderate, low). The high educational group scored much better on all health behaviors, whereas the lowest educational group scored the worst on the health behaviors. Tailoring health education messages using a cluster-based approach may be a promising new approach to address multiple behavior change more effectively.

Individual differences in the conceptualization of food across eating contexts

Individual differences in food-related knowledge structures were explored by applying schema theory to examine the categories 42 adults used to classify foods across four eating contexts. Food card-sort labels were organized into 12 categories, category salience for each person was evaluated, and cluster analysis was used to identify clusters of participants according to the salience of their categories. Clusters were further evaluated for complexity and consistency of category use across contexts. Seven food schema clusters were identified. Meal/time and Routine categories were the most salient overall and were used by most clusters. Well-being, Person, Source, Convenience, Meal component, and Food group categories varied in salience across clusters. The complexity and consistency of the food categories participants used across the contexts varied among the clusters. This study provided insight about cognitions that may underlie food-choice behaviors. Understanding individuals' food schemas could help nutrition professionals tailor messages to maximize health impact.

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.

Interleukin-6 genetic variability and adiposity: associations in two prospective cohorts and systematic review in 26,944 individuals

CONTEXT

IL-6 (IL6) is an immune-modulating cytokine associated with obesity in humans.

OBJECTIVE

Our objective was to assess the associations between the genetic variability of IL6 gene and adiposity and long-term changes.

DESIGN AND SUBJECTS

We determined the linkage disequilibrium-tagging single-nucleotide polymorphisms of IL6 gene in 2255 healthy women and 980 healthy men from two prospective cohorts. We also conducted a metaanalysis on the associations between polymorphism -174G>C (rs1800795) and adiposity.

RESULTS

IL6 haplotype 222211 (possessing rs2069827, rs1800797, rs1800795, rs1554606, rs2069861, and rs1818879; 1 codes the common and 2 codes the minor alleles) was consistently and significantly associated with greater waist circumference (P = 0.009 in men; P = 0.0003 in women) and baseline body mass index (BMI) (P = 0.01 in men; P = 0.046 in women) compared with the most common haplotype 111112. Haplotype 222211 was also associated with significantly higher early-adulthood BMI in women (P = 0.007). The haplotype-associated difference in BMI persisted significantly during the follow-up. A 5' promoter polymorphism, rs2069827, was consistently associated with significantly higher early-adulthood BMI, baseline BMI, and waist circumference in men (carriers vs. noncarriers, P = 0.01, 0.007, and 0.008) and women (P = 0.01, 0.10, and 0.0016). The data from this study and a metaanalysis of 26,944 individuals did not support substantial relations between the best-studied polymorphism, -174G>C, and adiposity.

CONCLUSIONS

Our data from two independent cohorts indicate that the variability of the IL6 gene is significantly associated with adiposity. Such associations are less likely to be caused by polymorphism -174G>C.

Dietary transition stages based on eating patterns and diet quality among Haitians of Montreal, Canada

OBJECTIVES

To identify dietary transition stages based on dietary patterns of adult Haitians having lived in Montreal for various lengths of time, and to assess associated dietary quality.

SUBJECTS

One hundred and eighty-one Haitians aged 25-60 years were recruited by the modified random digit dialling method.

DESIGN

Socio-economic, diet and lifestyle variables were documented by questionnaire. Three non-consecutive 24-hour dietary recalls were conducted over a 3-month period. Dietary patterns were studied using cluster analysis, and their association with proportion of lifetime in Canada and with socio-economic status (SES) was examined. Diet quality criteria were micronutrient adequacy and healthfulness based on dietary recommendations of the World Health Organization.

RESULTS

Four dietary phenotypes were identified which could roughly represent stages of dietary transition or acculturation (Traditional, Pre-Western, Western and Modern). Subjects in the 'Traditional' cluster were older and had lived for a significantly lower proportion of their lifetime in Canada; they also tended to be of lower SES. Diet quality was significantly higher in the 'Traditional' than the 'Western' type, particularly with respect to healthfulness. A significantly lower proportion of subjects complying with limited intake of total fat ( < 30%) and cholesterol ( < 45%) was observed in the 'Western' compared with other diet phenotypes. Less than 15% of all subjects consumed enough dietary fibre, irrespective of diet type.

CONCLUSION

Dietary transition stages could be identified on the basis of food patterns of Haitians according to the proportion of their lifetime in Canada. Encouraging the youth to retain the traditional food culture in its positive aspects would appear relevant

Diet and body constitution in relation to subgroups of breast cancer defined by tumour grade, proliferation and key cell cycle regulators

Background

The general lack of clear associations between diet and breast cancer in epidemiological studies may partly be explained by the fact that breast cancer is a heterogeneous disease that may have disparate genetic associations and different aetiological bases.

Method

A total of 346 incident breast cancers in a prospective cohort of 17,035 women enrolled in the Malmö Diet and Cancer study (Sweden) were subcategorized according to conventional pathology parameters, proliferation and expression of key cell cycle regulators. Subcategories were compared with prediagnostic diet and body measurements using analysis of variance.

Results

A large hip circumference and high body mass index were associated with high grade tumours (P = 0.03 and 0.009, respectively), whereas low energy and unadjusted fat intakes were associated with high proliferation (P = 0.03 and 0.004, respectively). Low intakes of saturated, monounsaturated and polyunsaturated fatty acids were also associated with high proliferation (P = 0.02, 0.004 and 0.003, respectively). Low energy and unadjusted fat intakes were associated with cyclin D₁ overexpression (P = 0.02 and 0.007, respectively), whereas cyclin E overexpression was positively correlated with fat intake. Oestrogen receptor status and expression of the tumour suppressor gene p27 were not associated with either diet or body constitution.

Conclusion

Low energy and low total fat (polyunsaturated fatty acids in particular) intakes, and high body mass index were associated with relatively more malignant breast tumours. Dietary behaviours and body constitution may be associated with specific types of breast cancer defined by conventional pathology parameters and cyclin D₁ and cyclin E expression. Further studies including healthy control individuals are needed to confirm our results.

Dietary patterns, insulin sensitivity and adiposity in the multi-ethnic Insulin Resistance Atherosclerosis Study population

Epidemiological investigations increasingly employ dietary-pattern techniques to fully integrate dietary data. The present study evaluated the relationship of dietary patterns identified by cluster analysis with measures of insulin sensitivity (SI) and adiposity in the multi-ethnic, multi-centre Insulin Resistance Atherosclerosis Study (IRAS, 1992–94). Cross-sectional data from 980 middle-aged adults, of whom 67% had normal and 33% had impaired glucose tolerance, were analysed. Usual dietary intake was obtained by an interviewer-administered, validated food-frequency questionnaire. Outcomes included SI, fasting insulin (FI), BMI and waist circumference. The relationship of dietary patterns to log(SI+1), log(FI), BMI and waist circumference was modelled with multivariable linear regressions. Cluster analysis identified six distinct diet patterns – ‘dark bread’, ‘wine’, ‘fruits’, ‘low-frequency eaters’, ‘fries’ and ‘white bread’. The ‘white bread’ and the ‘fries’ patterns over-represented the Hispanic IRAS population predominantly from two centres, while the ‘wine’ and ‘dark bread’ groups were dominated by non-Hispanic whites. The dietary patterns were associated significantly with each of the outcomes first at the crude, clinical level (P<0·001). Furthermore, they were significantly associated with FI, BMI and waist circumference independent of age, sex, race or ethnicity, clinic, family history of diabetes, smoking and activity (P<0.004), whereas significance was lost for SI. Studying the total dietary behaviour via a pattern approach allowed us to focus both on the qualitative and quantitative dimensions of diet. The present study identified highly consistent associations of distinct dietary patterns with measures of insulin resistance and adiposity, which are risk factors for diabetes and heart disease.

Both food habit change in the past and obesity status may influence the association between dietary factors and postmenopausal breast cancer

OBJECTIVE

Valid dietary data are essential when trying to identify whether or not one or more dietary exposures are responsible for disease. We examined diet composition in women who reported dietary change in the past compared with non-changers, and how the associations between dietary factors and postmenopausal breast cancer are influenced by dietary change, obesity status and misreporting of energy.

DESIGN

A population-based prospective cohort study. Data were obtained by a diet history method, anthropometrical measurements and an extensive lifestyle questionnaire including items on past food habit change.

SETTING

The Malmö Diet and Cancer (MDC) study, conducted in Malmö, Sweden.

SUBJECTS

A subsample of 12,781 women from the MDC cohort recruited from 1991 to 1996. A total of 428 postmenopausal women were diagnosed with incident breast cancer, during 9.2 years of follow-up.

RESULTS

Past food habit changers reported healthier food habits and lower energy intake compared with non-changers, a finding that raises issues regarding possible reporting biases. When excluding diet changers, the trend of increased breast cancer risk across omega-6 fatty acid quintiles was stronger, and a tendency of decreased risk emerged for 'fruit, berries and vegetables'. When excluding individuals with non-adequate reports of energy intake, risk estimates were similar to that of the whole sample. In women with body mass index < 27 kg m- 2, significant trends of increased breast cancer risk were seen for total fat and omega-6 fatty acids, and of decreased risk for 'fruit, berries and vegetables'.

CONCLUSIONS

This study indicates that both obesity and self-reported past food habit change may be important confounders of diet-breast cancer relationships. The study demonstrates that sensitivity analysis, through stratification, may facilitate interpretation of risk relationships and study results.

Past food habit change is related to obesity, lifestyle and socio-economic factors in the Malmo Diet and Cancer Cohort

Objectives

To examine if obesity status and socio-economic and lifestyle factors are associated with self-reported past food habit change, and also whether the level of obesity depends on the reason for change.

Design

Cross-sectional analysis within the Malmo Diet and Cancer (MDC) study using data from the baseline examination and the extensive socio-economic and lifestyle questionnaire including questions of past food habit change. The risk of having changed food habits in the past was examined using logistic regression. Mean differences in obesity status across categories of reasons for past food habit change were examined using analysis of variance.

Setting

Malmö, the third largest city in Sweden.

Subjects

A sub-sample (15 282 women and 9867 men) from the MDC cohort recruited from 1992 to 1996.

Results

Individuals with body mass index (BMI) >30 kg m−2 had an increased risk of having reported past food habit change compared with individuals with BMI <25 kg m−2 (odds ratio (OR) = 1.63, 95% confidence interval (CI) = 1.48–1.83 for women; OR = 1.53, 95% CI = 1.32–1.76 for men). The highest level of obesity was observed among individuals who had changed their diet due to reasons related to the metabolic syndrome. Changers were more likely to be highly educated and to live alone, be retired, ex-smokers and non-drinkers at baseline.

Conclusions

Because past food habit change is related to obesity and other lifestyle and socio-economic factors, a complex confounding situation may exist that could seriously influence observed relationships between diet and disease. Studies need to collect information on past food habit change and take this information into account in the analysis and when interpreting study outcomes.

Comparative strategies for using cluster analysis to assess dietary patterns

OBJECTIVES

To characterize dietary patterns using two different cluster analysis strategies.

DESIGN

In this cross-sectional study, diet information was assessed by five 24-hour recalls collected over 10 months. All foods were classified into 24 food subgroups. Demographic, health, and anthropometric data were collected via home visit.

SUBJECTS

One hundred seventy-nine community-dwelling adults, aged 66 to 87 years, in rural Pennsylvania.

STATISTICAL ANALYSIS

Cluster analysis was performed.

RESULTS

The methods differed in the food subgroups that clustered together. Both methods produced clusters that had significant differences in overall diet quality as assessed by Healthy Eating Index (HEI) scores. The clusters with higher HEI scores contained significantly higher amounts of most micronutrients. Both methods consistently clustered subgroups with high energy contribution (eg, fats and oils and dairy desserts) with a lower HEI score. Clusters resulting from the percent energy method were less likely to differentiate fruit and vegetable subgroups. The higher diet quality dietary pattern derived from the number of servings method resulted in more favorable weight status.

CONCLUSIONS

Cluster analysis of food subgroups using two different methods on the same data yielded similarities and dissimilarities in dietary patterns. Dietary patterns characterized by the number of servings method of analysis provided stronger association with weight status and was more sensitive to fruit and vegetable intake with regard to a more healthful dietary pattern within this sample. Public health recommendations should evaluate the methodology used to derive dietary patterns.

Physical activity and sedentary behavior patterns are associated with selected adolescent health risk behaviors

OBJECTIVE

Little is known about how physical activity (PA), sedentary behavior, and various adolescent health risk behaviors are associated. The objective of this study was to examine relationships between PA and sedentary behavior patterns and an array of risk behaviors, including leading causes of adolescent morbidity/mortality.

METHODS

Nationally representative self-reported data were collected (National Longitudinal Study of Adolescent Health; wave I: 1994-1995; II: 1996; N = 11957). Previously developed and validated cluster analyses identified 7 homogeneous groups of adolescents sharing PA and sedentary behaviors. Poisson regression predicted the relative risk of health risk behaviors, other weekly activities, and self-esteem across the 7 PA/sedentary behavior clusters controlling for demographics and socioeconomic status. Main outcome measures were adolescent risk behaviors (eg, truancy, cigarette smoking, sexual intercourse, delinquency), other weekly activities (eg, work, academic performance, sleep), self-esteem.

RESULTS

Relative to high television (TV) and video viewers, adolescents in clusters characterized by skating and video gaming, high overall sports and sports participation with parents, using neighborhood recreation center, strict parental control of TV, reporting few activities overall, and being active in school were less likely to participate in a range of risky behaviors, ranging from an adjusted risk ratio (ARR) of 0.42 (outcome: illegal drug use, cluster: strict parental control of TV) to 0.88 (outcome: violence, cluster: sports with parents). Active teens were less likely to have low self-esteem (eg, adolescents engaging in sports with parents, ARR: 0.73) and more likely to have higher grades (eg, active in school, ARR: 1.20).

CONCLUSIONS

Participation in a range of PA-related behaviors, particularly those characterized by high parental sports/exercise involvement, was associated with favorable adolescent risk profiles. Adolescents with high TV/video viewership were less likely to have positive risk behavior outcomes. Enhancing opportunities for PA and sport may have a beneficial effect on leading adolescent risk behaviors.

Misreporting of energy: prevalence, characteristics of misreporters and influence on observed risk estimates in the Malmö Diet and Cancer cohort

The present study investigates the prevalence of misreporting of energy in the Malmö Diet and Cancer cohort, and examines anthropometric, socio-economic and lifestyle characteristics of the misreporters. Further, the influence of excluding misreporters on risk estimates of post-menopausal breast cancer was examined. Information of reported energy intake (EI) was obtained from a modified diet history method. A questionnaire provided information on lifestyle and socio-economic characteristics. Individual physical activity level (PAL) was calculated from self-reported information on physical activity at work, leisure time physical activity and household work, and from estimates of hours of sleeping, self-care and passive time. Energy misreporting was defined as having a ratio of EI to BMR outside the 95 % CI limits of the calculated PAL. Logistic regression analysed the risk of being a low-energy reporter or a high-energy reporter. Almost 18 % of the women and 12 % of the men were classified as low-energy reporters, 2.8 % of the women and 3.5 % of the men were classified as high-energy reporters. In both genders high BMI, large waist circumference, short education and being a blue-collar worker were significantly associated with low-energy reporting. High-energy reporting was significantly associated with low BMI, living alone and current smoking. The results add support to the practice of energy adjustment as a means to reduce the influence of errors in risk assessment.

The influence of health behavior clusters on dietary change

BACKGROUND

The goal of this study was to identify cancer preventive health behavior clusters and to determine if clusters responded differently to a year-long intervention to increase fruit and vegetable consumption.

METHODS

The North Carolina Strategies for Improving Diet, Exercise, and Screening (NC STRIDES) is a health communications intervention (n = 595) among colorectal cancer survivors and a comparison population. Cluster analysis was used to identify nonoverlapping groups based on fruit and vegetable intake (servings/day), physical activity (minutes/day), multivitamin use (yes/no), and body mass index (kg/m2). Logistic regression was performed to assess positive change in fruit and vegetable servings, using the healthiest cluster as the reference group.

RESULTS

Five clusters were formed; they differed significantly by health behaviors and demographics. Clusters 1 and 2 (those following the "Healthy Choices" and "Eating Well" patterns) were eating more than 5 A Day before the intervention (8.6 and 6.9 servings/day), and did not show any increase. Cluster 3 ("Physically Active") reported an increase of 1.3 servings/day to reach 5.4 servings/day, and Clusters 4 and 5 ("Average Americans" and "Most Challenged") improved one serving/day for final intakes of 5.2 and 5.0 servings/day.

CONCLUSIONS

These findings illustrate some differences in magnitude of response to a fruit and vegetable intervention based on health behavior profiles. Creating clusters or other categories from baseline health behaviors may help to further improve targeting and/or tailoring in health promotion interventions.

Adolescent physical activity and sedentary behavior: patterning and long-term maintenance

BACKGROUND

Little is known about physical activity (PA) and sedentary behavior patterning or its impact on long-term PA sustainability, particularly during the critical transition from adolescence to adulthood.

METHODS

Nationally representative self-reported data were collected (National Longitudinal Study of Adolescent Health: Wave I, 1994-1995; Wave II, 1996; Wave III, 2001-2002). Cluster analyses identified homogeneous groups of adolescents with similar PA and sedentary behaviors. Logistic regression predicted odds of meeting national activity recommendations in adolescence and young adulthood.

RESULTS

Seven clusters were characterized as follows: C1, high television (TV)/video, video gaming; C2, high skating, video gaming; C3, high sports participation with parents, high overall sports participation; C4, use of neighborhood recreation centers, high sports participation; C5, TV viewing limited by parents, moderate participation in school physical education (PE); C6, low parental TV control, reporting few activities overall; C7, active in school (team/individual sports, academic clubs, and PE). Odds of adolescents meeting PA recommendations were highest in C2 (odds ratio=13.1), C3 (5.8), C4 (4.2), and C7 (4.3) compared to C1. Independent of adolescent PA, absolute odds of meeting recommendations as young adults declined but were still relatively high in these clusters, indicating greater long-term PA sustainability. By young adulthood, however, overall PA declined dramatically in skaters/gamers (C2) and was notably low among those with TV viewing limited by parents (C5).

CONCLUSIONS

While odds of meeting PA guidelines in adulthood declined in all clusters, the magnitude of this decline varied by cluster (declining most dramatically in skaters/gamers), providing insights into where to target effective intervention strategies that promote sustainable PA behaviors.

Dietary patterns and health outcomes

A systematic review of the literature on dietary patterns (multiple dietary components operationalized as a single exposure) in relation to nutrient adequacy, lifestyle and demographic variables, and health outcome was conducted. Most of the published reports on the subject have used one of two methods to determine dietary patterns: (a) diet indexes or scores that assess compliance with prevailing dietary guidance as dietary patterns, and (b) data-driven methods that use factor or cluster analysis to derive dietary patterns. Irrespective of the approach used, patterns characterized by fruit/vegetable/whole grain/fish/poultry consumption generally have been reported to relate to micronutrient intake, and to selected biomarkers of dietary exposure and disease risk in the expected direction. Age, income, and education have been reported to be among positive predictors of the so-called more healthful dietary patterns. An inverse association of healthful dietary patterns with all-cause mortality and cardiovascular disease risk was reported in most studies. However, the magnitude of risk reduction was modest and was attenuated after control for confounders. Few published studies showed an association between risk of most incident cancers and dietary patterns. Both of the currently used approaches for extracting dietary patterns have limitations, are subject to dietary measurement errors, and have not generated new diet and disease hypotheses.