The reliability of an adolescent dietary pattern identified using reduced-rank regression: comparison of a FFQ and 3 d food record

An Oxylipin-Related Nutrient Pattern and Risk of Type 1 Diabetes in the Diabetes Autoimmunity Study in the Young (DAISY)

Oxylipins, pro-inflammatory and pro-resolving lipid mediators, are associated with the risk of type 1 diabetes (T1D) and may be influenced by diet. This study aimed to develop a nutrient pattern related to oxylipin profiles and test their associations with the risk of T1D among youth. The nutrient patterns were developed with a reduced rank regression in a nested case-control study (n = 335) within the Diabetes Autoimmunity Study in the Young (DAISY), a longitudinal cohort of children at risk of T1D. The oxylipin profiles (adjusted for genetic predictors) were the response variables. The nutrient patterns were tested in the case-control study (n = 69 T1D cases, 69 controls), then validated in the DAISY cohort using a joint Cox proportional hazards model (n = 1933, including 81 T1D cases). The first nutrient pattern (NP1) was characterized by low beta cryptoxanthin, flavanone, vitamin C, total sugars and iron, and high lycopene, anthocyanidins, linoleic acid and sodium. After adjusting for T1D family history, the HLA genotype, sex and race/ethnicity, NP1 was associated with a lower risk of T1D in the nested case-control study (OR: 0.44, p = 0.0126). NP1 was not associated with the risk of T1D (HR: 0.54, p-value = 0.1829) in the full DAISY cohort. Future studies are needed to confirm the nested case-control findings and investigate the modifiable factors for oxylipins.

Prospective Associations of Sugar-Sweetened Beverage Consumption During Adolescence with Body Composition and Bone Mass at Early Adulthood

BACKGROUND

Adolescents have a higher consumption of sugar-sweetened beverages (SSBs) than other age groups, but little is known of the impact of SSB intake during adolescence on body composition and bone mass in early adulthood.

OBJECTIVES

Associations of SSB intake from 14 to 20 y with fat, lean, and bone mass at 20 y of age were evaluated.

METHODS

Study participants were 1137 offspring (562 females) from the Raine Study. Food intake, including SSB consumption in servings/d (1 serving = 250 mL), was estimated using FFQs at 14, 17, and 20 y of age. DXA scanning at 20 y measured whole body fat mass, lean mass, and bone mineral content (BMC). Using latent class growth analysis, 4 SSB intake trajectory classes were identified: consistently low (n = 540, intakes mostly <0.5 serving/d), increasing (n = 65), decreasing (n = 258), and consistently high (n = 274, intakes mostly >1.3 servings/d).

RESULTS

Median total SSB intake was 0.8, 0.7, and 0.5 serving/d, and median carbonated SSB intake was 0.3, 0.3, and 0.4 serving/d at 14, 17, and 20 y, respectively. Mean ± SD BMI (in kg/m2) was 23.9 ± 4.2 at 20 y. After adjustment for covariates including sex, demographic, energy intake, and maternal factors, individuals with "consistently high" SSB consumption had significantly higher total body fat mass at 20 y than those with "consistently low" consumption (23.3 ± 0.6 compared with 21.2 ± 0.4 kg, P = 0.004), which remained significant after further adjustment for "Healthy" and "Western" dietary patterns (23.2 ± 0.6 compared with 21.2 ± 0.4 kg, P = 0.011). No significant associations were observed between SSB intake trajectory classes and lean body mass or BMC at 20 y.

CONCLUSIONS

In this cohort, consistently higher consumption of SSBs in adolescence and early adulthood are associated with increased fat mass but not with bone mass at 20 y of age.

'Energy-Dense, High-SFA and Low-Fiber' Dietary Pattern Lowered Adiponectin but Not Leptin Concentration of Breast Cancer Survivors

Dietary pattern (DP) and its relationship with disease biomarkers have received recognition in nutritional epidemiology investigations. However, DP relationships with adipokines (i.e., adiponectin and leptin) among breast cancer survivors remain unclear. Therefore, we assessed relationships between DP and high-molecular weight (HMW) adiponectin and leptin concentration among breast cancer survivors. This cross-sectional study involved 128 breast cancer survivors who attended the oncology outpatient clinic at two main government hospitals in the East Coast of Peninsular Malaysia. The serum concentration of HMW adiponectin and leptin were measured using enzyme-linked immunosorbent assay (ELISA) kits. A reduced rank regression method was used to analyze DP. Relationships between DP with HMW adiponectin and leptin were examined using regression models. The findings show that with every 1-unit increase in the ‘energy-dense, high-SFA, low-fiber’ DP z-score, there was a reduction by 0.41 μg/mL in HMW adiponectin which was independent of age, BMI, education level, occupation status, cancer stage, and duration since diagnosis. A similar relationship with leptin concentration was not observed. In conclusion, the ‘energy-dense, high-saturated fat and low-fiber’ DP, which is characterized by high intake levels of sugar-sweetened drinks and fat-based spreads but low intake of fruits and vegetables, is an unhealthy dietary pattern and unfavorable for HMW adiponectin concentration, but not for leptin. These findings could serve as a basis in developing specific preventive strategies that are tailored to the growing population of breast cancer survivors.

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

BACKGROUND

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

OBJECTIVE

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

DESIGN

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

PARTICIPANTS AND SETTING

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

MAIN OUTCOME MEASURES

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

STATISTICAL ANALYSIS

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

RESULTS

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

CONCLUSIONS

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

Dietary fibre intake and its associations with depressive symptoms in a prospective adolescent cohort

Depression is a major cause of disability in adolescents. Higher dietary fibre intake has been associated with lower depressive symptoms in adults, but there is a lack of research in adolescents. We examined the association between dietary fibre intake (Commonwealth Scientific and Industrial Research Organisation (CSIRO) FFQ) and depressive symptoms (Beck Depression Inventory for Youth) in adolescents with prospective data from the Raine Study Gen2 14- and 17-year follow-ups (n 1260 and 653). Odds of moderate/extreme (clinically relevant) depressive symptoms by quartile of fibre intake were calculated using mixed-effects logistic regression for all participants, in a paired sample without moderate/extreme depressive symptoms at 14 years and in a sub-sample of participants with available inflammatory data at the ages of 14 and 17 years (n 718 and 547). Odds of moderate/extreme depressive symptoms were lower in the fourth (highest) quartile of overall fibre intake (OR 0·273, 95 % CI 0·09, 0·81) compared with the first (lowest) quartile, adjusting for sex, age, energy intake, adiposity, and family and lifestyle factors. However, further adjustment for dietary patterns attenuated the results. Associations of depressive symptoms with cereal or fruit and vegetable fibre intake were not significant in the final model. Adjustment for inflammation had no effect on OR. The association between a higher dietary fibre intake and lower odds of clinically relevant depressive symptoms may be more reflective of a high-fibre diet with all its accompanying nutrients than of an independent effect of fibre.

Advances in dietary pattern analysis in nutritional epidemiology

Background and Purpose

It used to be a common practice in the field of nutritional epidemiology to analyze separate nutrients, foods, or food groups. However, in reality, nutrients and foods are consumed in combination. The introduction of dietary patterns (DP) and their analysis has revolutionized this field, making it possible to take into account the synergistic effects of foods and to account for the complex interaction among nutrients and foods. Three approaches of DP analysis exist: (1) the hypothesis-based approach (based on prior knowledge regarding the current understanding of dietary components and their health relation), (2) the exploratory approach (solely relying on dietary intake data), and (3) the hybrid approach (a combination of both approaches). During the recent past, complementary approaches for DP analysis have emerged both conceptually and methodologically.

Method

We have summarized the recent developments that include incorporating the Treelet transformation method as a complementary exploratory approach in a narrative review.

Results

Uses, peculiarities, strengths, limitations, and scope of recent developments in DP analysis are outlined. Next, the narrative review gives an overview of the literature that takes into account potential relevant dietary-related factors, specifically the metabolome and the gut microbiome in DP analysis. Then the review deals with the aspect of data processing that is needed prior to DP analysis, particularly when dietary data arise from assessment methods other than the long-established food frequency questionnaire. Lastly, potential opportunities for upcoming DP analysis are summarized in the outlook.

Conclusion

Biological factors like the metabolome and the microbiome are crucial to understand diet-disease relationships. Therefore, the inclusion of these factors in DP analysis might provide deeper insights.

Validity and reliability of a simplified food frequency questionnaire: a cross sectional study among physical health examination adults in southwest region of China

Background

In China, many people are regarded suitable for participating in regular physical examination for diagnosis and prevention of diseases. Some simplified food frequency questionnaires have been designed and used; however, the accuracy of the questionnaire is absent. This study aimed to examine the reliability and validity of simplified food frequency questionnaire (SFFQ) used among adults undergoing physical examination in southwest region of China.

Methods

This was a cross-sectional study conducted among physical health examination adults in the Southwest region of China. A total of 239 participants aged 20–65 were included from February 2019 to June 2019. The performance of SFFQ was evaluated by means of a three-day 24-h dietary record (3R24). The relative validity and agreement was assessed by Pearson’s correlation and intra-class correlation coefficients (ICC), respectively.

Results

The median energy-adjusted ICC of food groups between SFFQ2 and SFFQ1 was 0.59 (range: 0.49–0.73) and the ICC of nutrients was 0.47(range: 0.39–0.76). The Pearson correlation showed a valid comparisons between SFFQ1 and 3R24, ranging from -0.086 to 0.93 for food and 0.21 to 0.71 for nutrition, respectively. The energy-adjustment slightly increased the correlation coefficients.

Conclusions

The reliability and validity of SFFQ was acceptable, and it could be an appropriate dietary assessment tool for the future epidemiological studies conducted among physical health examination adults of southwest China.

Trial registration

CHiCTR, ChiCTR1900020934, Registered 22 January 2019, https://www.chictr.org.cn/edit.aspx?pid=35414&htm=4.

Relative validity of FFQ to assess food items, energy, macronutrient and micronutrient intake in children and adolescents: a systematic review with meta-analysis

FFQ are one of the most widely used tools of research into nutritional epidemiology, and many studies have been conducted in several countries using this dietary assessment method. The present study aimed to evaluate the relative validity of FFQ, in comparison with other methods, in assessing dietary intake of children and adolescents, through a systematic review. Four electronic databases (Embase, PubMed, Scopus and Web of Science) found sixty-seven articles, which met the inclusion criteria (healthy children and adolescents from 3 to 18 years of age; journal articles written in English, Spanish and Portuguese between 1988 and March 2019; results showing the comparison between the FFQ with other methods of assessment of dietary intake). The articles were analysed by two independent reviewers. A meta-analysis was conducted using correlation coefficients as estimate effects between the FFQ and the reference standard method. Subgroup analysis and meta-regression were performed to identify the probable source of heterogeneity. In fifty-five of the sixty-seven studies, a single dietary assessment method was used to evaluate the FFQ; nine combined the two methods and three used three reference methods. The most widely used reference method was the 24-h recall, followed by the food record. The overall relative validity of the FFQ to estimate energy, macronutrient, certain micronutrient and certain food item intakes in children and adolescents may be considered weak. The study protocol was registered in PROSPERO under number CRD42016038706.

Dietary fibre intake and its association with inflammatory markers in adolescents

A high dietary fibre intake has been associated with improvements in inflammatory conditions in adults. However, little is known on whether associations between dietary fibre and inflammation are evident during adolescence. We examined the relationship between dietary fibre intake measured by FFQ and the inflammatory marker high-sensitivity C-reactive protein (hs-CRP) and the adipokines leptin and adiponectin cross-sectionally in 17-year-olds participating in the Raine Study (n 621). In weighted analysis using tobit and linear regression, and after excluding participants with hs-CRP > 10 mg/l, higher total dietary fibre intake (per 5 g/d) was significantly associated with lower leptin (β = -0·13, 95 % CI -0·17, -0·09) and adiponectin (β = -0·28, 95 % CI -0·49, -0·07), but not hs-CRP, in unadjusted analyses. These associations were no longer significant after adjustment for sex, anthropometry and a number of lifestyle factors. However, higher cereal and grain fibre intake was significantly associated with lower leptin (β = -0·06, 95 % CI -0·10, -0·01) in fully adjusted analysis. Our findings suggest that a higher intake of cereal and grain fibre may contribute to lower leptin in adolescents. This may contribute to reductions in low-grade chronic inflammation and improved health outcomes.

Associations of an empirical dietary pattern with cardiometabolic risk factors in Malaysian adolescents

BACKGROUND

This study aimed to identify a dietary pattern (DP) characterised mainly by high intakes of free sugar and other nutrients hypothesised to be associated with obesity such as dietary energy density (DED), percentage of energy from total fat and fibre density in adolescents from three southern states of Peninsular Malaysia, and its associations with cardiometabolic risk factors.

METHODS

This is a cross-sectional study among 335 adolescents who provided both dietary information assessed using a validated food frequency questionnaire (FFQ) and biochemical parameters including lipid profile, blood glucose, serum insulin and homeostatic model assessment-insulin resistance (HOMA-IR). Anthropometric measurements included weight (kg), height (cm) and waist circumference (cm), while body mass index (BMI) in kg/m2 was estimated, respectively. Reduced rank regression (RRR) identified a DP with percentage of energy from sugar and total fat, DED and fibre density intake as response variables.

RESULTS

The identified 'high sugar, high fibre, high DED and low fat' DP was characterised by high intakes of sugar-sweetened beverages, fruits, sweets and low intakes of meat and cereal. Adolescents in the highest tertile of the identified DP had about 3.0 (OR = 2.7; 95%CI: 1.3, 5.6) and 2.0 (OR = 1.9; 95%CI: 1.0, 3.5) times higher odds of having dyslipideamia or elevated total cholesterol and LDL-cholesterol level, respectively compared to adolescents in the lowest tertile DP after adjusting for sex, school location, maternal education, physical activity, dietary misreporting and BMI z-score. This DP was not significantly associated with overweight and obesity.

CONCLUSIONS

Higher adherence to a DP characterised mainly by free sugars and DED was associated with greater odds of having dyslipideamia, elevated total cholesterol and LDL-cholesterol levels in Malaysian adolescents.

Dietary Patterns and Childhood Obesity Risk: A Systematic Review

Background: Childhood overweight and obesity are recognized as predictors of the risk of obesity in adulthood. The aim of this systematic literature review was to determine the association between dietary pattern and obesity risk among children. Methods: Articles were selected from databases (Cochrane Library, Lilacs, Eric, Livivo, and PubMed/Medline), without limitations regarding language or date. Database-specific search terms included the key words "obesity," "diet," "dietary pattern," "childhood," "children," "adolescents," and relevant synonyms. The review included studies that reported the assessment of the dietary pattern in childhood and that correlated eating patterns with the obesity risk through cluster analysis (CA) and/or factor analysis and/or principal component analysis and presented odds ratios (ORs). The methodology of the selected studies was evaluated using the JBI Critical Appraisal Checklist for Analytical Cross-Sectional Studies. Owing to the heterogeneity among the assessments of the association of dietary patterns and obesity, the results are described narratively. Results: Using a selection process in two phases, 16 articles were included. Fifteen studies used a cross-sectional design, and one case-control study. The included studies showed variation in sample size (range = 232 to 10,187 children/adolescents) and age (range = 1-19 years old). The studies reported between two and five dietary patterns each. The OR for the relationship between the dietary pattern and the risk of childhood obesity ranged from OR = 1.02; confidence interval (95% CI) (0.91-1.15) to OR = 3.55; 95% CI (1.80-7.03). In this study, the dietary patterns identified by the studies were given different names. The food intake patterns identified could, in most factor or CA studies, be categorized as (1) potentially obesogenic foods that increased risk of becoming overweight (including fatty cheeses, sugary drinks, processed foods, fast food, candies, snacks, cakes, animal products, whole milk, and refined grains) or (2) food classified as healthy with the weakest association with the risk of becoming overweight or obese (including low levels of sugar and fat and high levels of fruits, vegetables, whole grains, fish, nuts, legumes, and yogurt). Conclusion: Overall, the results indicated from most studies that a diet with a lower percentage of obesogenic foods should be effective in reducing the risk of developing obesity.

Cardiometabolic Risk Factors and Physical Activity Patterns Maximizing Fitness and Minimizing Fatness Variation in Malaysian Adolescents: A Novel Application of Reduced Rank Regression

Patterns of physical activity (PA) that optimize both fitness and fatness may better predict cardiometabolic health. Reduced rank regression (RRR) was applied to identify combinations of the type (e.g., football vs. skipping), location and timing of activity, explaining variation in cardiorespiratory fitness (CRF) and Body Mass Index (BMI). Multivariable regressions estimated longitudinal associations of PA pattern scores with cardiometabolic health in n = 579 adolescents aged 13–17 years from the Malaysian Health and Adolescent Longitudinal Research Team study. PA pattern scores in boys were associated with higher fitness (r = 0.3) and lower fatness (r = −0.3); however, in girls, pattern scores were only associated with higher fitness (r = 0.4) (fatness, r = −0.1). Pattern scores changed by β = −0.01 (95% confidence interval (CI) −0.04, 0.03) and β = −0.08 (95% CI −0.1, −0.06) per year from 13 to 17 years in boys and girls respectively. Higher CRF and lower BMI were associated with better cardiometabolic health at 17 years, but PA pattern scores were not in either cross-sectional or longitudinal models. RRR identified sex-specific PA patterns associated with fitness and fatness but the total variation they explained was small. PA pattern scores changed little through adolescence, which may explain the limited evidence on health associations. Objective PA measurement may improve RRR for identifying optimal PA patterns for cardiometabolic health.

Exploratory dietary patterns: a systematic review of methods applied in pan-European studies and of validation studies

Besides a priori approaches, using previous knowledge about food characteristics, exploratory dietary pattern (DP) methods, using data at hand, are commonly applied. This systematic literature review aimed to identify exploratory methods on DP in pan-European studies and to inform the development of the DEterminants of DIet and Physical ACtivity (DEDIPAC) toolbox of methods suitable for use in future European studies. The search was conducted in three databases on prospective studies in healthy, free-living people across the whole life span. To identify validated DP methods, an additional search without regional restrictions was conducted. Studies including at least two European countries were retained. The search resulted in six pan-European studies applying principal component/factor analysis (PC/FA) (n 5) or cluster analysis (n 2). The criteria to retain PC/factors ranged from the application of the eigenvalue>1 criterion, the scree plot and/or the interpretability criterion. Furthermore, seven validation studies were identified: DP, derived by PC/FA (n 6) or reduced rank regression (RRR) (n 1) were compared using dietary information from FFQ (n 6) or dietary history (n 1) as study instrument and dietary records (n 6) or 24-h dietary recalls (n 1) as reference. The correlation coefficients for the derived DP ranged from modest to high. To conclude, PC/FA was predominantly applied using the eigenvalue criterion and scree plot to retain DP, but a better description of the applied criteria is highly recommended to enable a standardised application of the method. Research gaps were identified for the methods cluster analysis and RRR, as well as for validation studies on DP.

Social Gradients and Physical Activity Trends in an Obesogenic Dietary Pattern: Cross-Sectional Analysis of the UK National Diet and Nutrition Survey 2008-2014

An energy-dense, high-fat, low-fibre dietary pattern has been prospectively associated with the development of obesity in childhood but is population-specific, which limits translating the pattern into interventions. We explored the generalisability and correlates of this obesogenic dietary pattern in the UK National Diet and Nutrition Survey (NDNS) for the first time. Data came from participants (n = 4636 children and n = 4738 adults) with 4-day food diaries in NDNS 2008-2014. Reduced rank regression was applied to 51 food groups to explain variation in energy density, fibre and fat intake. Consistency of the pattern in population subgroups (according to sex, age, occupation and income) was compared with the whole sample pattern using coefficients of congruence (COC). Pattern correlates (sociodemographic, survey year, physical activity and eating related behaviours) were explored using multiple linear regression. Food group loadings were similar to the previously identified obesogenic dietary pattern and were generalisable across all sub-groups (COC: 0.93-0.99). An obesogenic diet was associated with eating takeaways, being omnivorous, a manual household occupation and lower household income in both adults and children (p < 0.0001). Dieting for weight loss, being older, more physically active and less sedentary was associated with a less obesogenic diet among adults (p < 0.0001). Future experimental studies should investigate if changes in this obesogenic pattern could be used to monitor the effectiveness of obesity prevention policies or develop personalised interventions.

Process service quality evaluation based on Dempster-Shafer theory and support vector machine

Human involvement influences traditional service quality evaluations, which triggers an evaluation’s low accuracy, poor reliability and less impressive predictability. This paper proposes a method by employing a support vector machine (SVM) and Dempster-Shafer evidence theory to evaluate the service quality of a production process by handling a high number of input features with a low sampling data set, which is called SVMs-DS. Features that can affect production quality are extracted by a large number of sensors. Preprocessing steps such as feature simplification and normalization are reduced. Based on three individual SVM models, the basic probability assignments (BPAs) are constructed, which can help the evaluation in a qualitative and quantitative way. The process service quality evaluation results are validated by the Dempster rules; the decision threshold to resolve conflicting results is generated from three SVM models. A case study is presented to demonstrate the effectiveness of the SVMs-DS method.

Determinants of a dietary pattern linked with greater metabolic risk and its tracking during adolescence

BACKGROUND

Although growing evidence suggests that dietary patterns associated with noncommunicable diseases in adulthood may develop early in life, when these are established, as well as their determinants, remains unclear.

METHODS

We examined determinants and tracking of a dietary pattern (DP) associated with metabolic risk and its key food groups among 860 adolescents in the Western Australian Pregnancy (Raine) Cohort study. Food intake was reported using a food frequency questionnaire (FFQ) at 14 and 17 years. Z-scores for an 'energy-dense, high-fat, low-fibre' DP were estimated by applying reduced rank regression at both ages. Tracking was based on the predictive value (PV) of remaining in the DPZ-score or food intake quartile at 14 and 17 years. Early-life exposures included: maternal age; maternal pre-pregnancy body mass index; parent smoking status during pregnancy; and parent socio-economic position (SEP) at 14 and 17 years. Associations between the DPZ-scores, early-life factors and SEP were analysed using regression analysis.

RESULTS

Dietary tracking was strongest among boys with high DPZ-scores, high intakes of processed meat, low-fibre bread, crisps and savoury snacks (PV > 1) and the lowest intakes of vegetables, fruit and legumes. Lower maternal education (β = 0.09, P = 0.002 at 14 years; β = 0.14, P < 0.001 at 17 years) and lower maternal age at birth (β = 0.09, P = 0.003 at 14 years; β = 0.11, P = 0.004 at 17 years) were positively associated with higher DPZ-scores.

CONCLUSIONS

An energy-dense, high-fat, low-fibre dietary pattern tracks more strongly among adolescent boys who have high scores for this pattern at 14 years of age. These findings highlight target foods and population subgroups for early interventions aiming to improve dietary behaviours.

Identification of dietary patterns associated with obesity in a nationally representative survey of Canadian adults: application of a priori, hybrid, and simplified dietary pattern techniques

Background: Analyzing the effects of dietary patterns is an important approach for examining the complex role of nutrition in the etiology of obesity and chronic diseases.Objectives: The objectives of this study were to characterize the dietary patterns of Canadians with the use of a priori, hybrid, and simplified dietary pattern techniques, and to compare the associations of these patterns with obesity risk in individuals with and without chronic diseases (unhealthy and healthy obesity).Design: Dietary recalls from 11,748 participants (≥18 y of age) in the cross-sectional, nationally representative Canadian Community Health Survey 2.2 were used. A priori dietary pattern was characterized with the use of the previously validated 2015 Dietary Guidelines for Americans Adherence Index (DGAI). Weighted partial least squares (hybrid method) was used to derive an energy-dense (ED), high-fat (HF), low-fiber density (LFD) dietary pattern with the use of 38 food groups. The associations of derived dietary patterns with disease outcomes were then tested with the use of multinomial logistic regression.Results: An ED, HF, and LFD dietary pattern had high positive loadings for fast foods, carbonated drinks, and refined grains, and high negative loadings for whole fruits and vegetables (≥|0.17|). Food groups with a high loading were summed to form a simplified dietary pattern score. Moving from the first (healthiest) to the fourth (least healthy) quartiles of the ED, HF, and LFD pattern and the simplified dietary pattern scores was associated with increasingly elevated ORs for unhealthy obesity, with individuals in quartile 4 having an OR of 2.57 (95% CI: 1.75, 3.76) and 2.73 (95% CI: 1.88, 3.98), respectively (P-trend < 0.0001). Individuals who adhered the most to the 2015 DGAI recommendations (quartile 4) had a 53% lower OR of unhealthy obesity (P-trend < 0.0001). The associations of dietary patterns with healthy obesity and unhealthy nonobesity were weaker, albeit significant.Conclusions: Consuming an ED, HF, and LFD dietary pattern and lack of adherence to the recommendations of the 2015 DGAI were associated with a significantly higher risk of obesity with and without accompanying chronic diseases.

Using reduced rank regression methods to identify dietary patterns associated with obesity: a cross-country study among European and Australian adolescents

This study aims to examine repeatability of reduced rank regression (RRR) methods in calculating dietary patterns (DP) and cross-sectional associations with overweight (OW)/obesity across European and Australian samples of adolescents. Data from two cross-sectional surveys in Europe (2006/2007 Healthy Lifestyle in Europe by Nutrition in Adolescence study, including 1954 adolescents, 12-17 years) and Australia (2007 National Children's Nutrition and Physical Activity Survey, including 1498 adolescents, 12-16 years) were used. Dietary intake was measured using two non-consecutive, 24-h recalls. RRR was used to identify DP using dietary energy density, fibre density and percentage of energy intake from fat as the intermediate variables. Associations between DP scores and body mass/fat were examined using multivariable linear and logistic regression as appropriate, stratified by sex. The first DP extracted (labelled 'energy dense, high fat, low fibre') explained 47 and 31 % of the response variation in Australian and European adolescents, respectively. It was similar for European and Australian adolescents and characterised by higher consumption of biscuits/cakes, chocolate/confectionery, crisps/savoury snacks, sugar-sweetened beverages, and lower consumption of yogurt, high-fibre bread, vegetables and fresh fruit. DP scores were inversely associated with BMI z-scores in Australian adolescent boys and borderline inverse in European adolescent boys (so as with %BF). Similarly, a lower likelihood for OW in boys was observed with higher DP scores in both surveys. No such relationships were observed in adolescent girls. In conclusion, the DP identified in this cross-country study was comparable for European and Australian adolescents, demonstrating robustness of the RRR method in calculating DP among populations. However, longitudinal designs are more relevant when studying diet-obesity associations, to prevent reverse causality.

Evaluating dietary patterns: the role of reduced rank regression

PURPOSE OF REVIEW

The purpose of review is to present methodological issues as well as most relevant recent developments on the application of a statistical method to derive dietary patterns: reduced rank regression (RRR). RRR can be used efficiently in nutritional epidemiology to identify dietary patterns associated with selected response variables that have known relations with a disease outcome of interest. This has the advantage of building on a priori knowledge of biological relations, by including plausible intermediates between diet and the outcome of interest.

RECENT FINDINGS

This statistical method has been applied first in nutritional epidemiology about 1 decade ago. Since then, more than 60 publications were published applying the RRR. This method is considerably dependent on an adequate selection of response variables. These response sets were most often a combination of nutrients or of selected endogenous biomarkers. But also variables of intermediate clinical phenotype or contaminants were selected. However, applying this method, several methodological issues, such as, for example, selection of responses, simplification, and validation of the derived pattern should be taken into account.

SUMMARY

RRR is a modern statistical method to derive dietary patterns that can be used to test specific hypothesis on pathways from diet to development of a disease.

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

BACKGROUND

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

OBJECTIVE

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

METHODS

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

STATISTICAL ANALYSIS

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

RESULTS

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

CONCLUSIONS

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

Clustering of Dietary Patterns, Lifestyles, and Overweight among Spanish Children and Adolescents in the ANIBES Study

Weight gain has been associated with behaviors related to diet, sedentary lifestyle, and physical activity. We investigated dietary patterns and possible meaningful clustering of physical activity, sedentary behavior, and sleep time in Spanish children and adolescents and whether the identified clusters could be associated with overweight. Analysis was based on a subsample (n = 415) of the cross-sectional ANIBES study in Spain. We performed exploratory factor analysis and subsequent cluster analysis of dietary patterns, physical activity, sedentary behaviors, and sleep time. Logistic regression analysis was used to explore the association between the cluster solutions and overweight. Factor analysis identified four dietary patterns, one reflecting a profile closer to the traditional Mediterranean diet. Dietary patterns, physical activity behaviors, sedentary behaviors and sleep time on weekdays in Spanish children and adolescents clustered into two different groups. A low physical activity-poorer diet lifestyle pattern, which included a higher proportion of girls, and a high physical activity, low sedentary behavior, longer sleep duration, healthier diet lifestyle pattern. Although increased risk of being overweight was not significant, the Prevalence Ratios (PRs) for the low physical activity-poorer diet lifestyle pattern were >1 in children and in adolescents. The healthier lifestyle pattern included lower proportions of children and adolescents from low socioeconomic status backgrounds.

Identification of a dietary pattern prospectively associated with bone mass in Australian young adults

BACKGROUND

Relatively little is known about the relations between dietary patterns and bone health in adolescence, which is a period of substantial bone mass accrual.

OBJECTIVES

We derived dietary patterns that were hypothesized to be related to bone health on the basis of their protein, calcium, and potassium contents and investigated their prospective associations with bone mineral density (BMD), bone area, and bone mineral content (BMC) in a cohort of young adults.

DESIGN

The study included 1024 young adults born to mothers who were participating in the Western Australian Pregnancy Cohort (Raine) Study. Dietary information was obtained from food-frequency questionnaires at 14 and 17 y of age. Dietary patterns were characterized according to protein, calcium, and potassium intakes with the use of reduced-rank regression. BMD, bone area, and BMC were estimated with the use of a total body dual-energy X-ray absorptiometry scan at 20 y of age.

RESULTS

We identified 2 major dietary patterns. The first pattern was positively correlated with intakes of protein, calcium, and potassium and had high factor loadings for low-fat dairy products, whole grains, and vegetables. The second pattern was positively correlated with protein intake but negatively correlated with intakes of calcium and potassium and had high factor loadings for meat, poultry, fish, and eggs. After adjustment for anthropometric, sociodemographic, and lifestyle factors, a higher z score for the first pattern at 14 y of age was positively associated with BMD and BMC at 20 y of age [differences: 8.6 mg/cm(2) (95% CI: 3.0, 14.1 mg/cm(2)) and 21.9 g (95% CI: 6.5, 37.3 g), respectively, per SD increase in z score]. The z score for this same pattern at 17 y of age was not associated with bone outcomes at 20 y of age. The second pattern at 14 or 17 y of age was not associated with BMD, BMC, or bone area.

CONCLUSIONS

A dietary pattern characterized by high intakes of protein, calcium, and potassium in midadolescence was associated with higher BMD and BMC at 20 y of age. Our results indicate that high consumption of low-fat dairy products, whole grains, and vegetables in adolescence are associated with beneficial effects on bone development.

Identification of a dietary pattern associated with greater cardiometabolic risk in adolescence

BACKGROUND AND AIMS

Energy dense, high fat, low fibre diets may contribute to obesity in young people, however their relationships with other cardiometabolic risk factors are unclear. We examined associations between an 'energy-dense, high-fat and low-fibre' dietary pattern (DP) and cardiometabolic risk factors, and the tracking of this DP in adolescence.

METHODS AND RESULTS

Data was sourced from participants in the Western Australian Pregnancy (Raine) Cohort Study. At 14 and 17 y, dietary intake, anthropometric and biochemical data were measured and z-scores for an 'energy dense, high fat and low fibre' DP were estimated using reduced rank regression (RRR). Associations between DP z-scores and cardiometabolic risk factors were examined using regression models. Tracking of DP z-scores was assessed using Pearson's correlation coefficient. A 1 SD unit increase in DP z-score between 14 and 17 y was associated with a 20% greater odds of high metabolic risk (95% CI: 1.01, 1.41) and a 0.04 mmol/L higher fasting glucose in boys (95% CI: 0.01, 0.08); a 28% greater odds of a high-waist circumference (95% CI: 1.00, 1.63) in girls. An increase of 3% and 4% was observed for insulin and HOMA (95% CI: 1%, 7%), respectively, in boys and girls, for every 1 SD increase in DP z-score and independently of BMI. The DP showed moderate tracking between 14 and 17 y of age (r = 0.51 for boys, r = 0.45 for girls).

CONCLUSION

An 'energy dense, high fat, low fibre' DP is positively associated with cardiometabolic risk factors and tends to persist throughout adolescence.

Glycemic modulation in neuro-oncology: experience and future directions using a modified Atkins diet for high-grade brain tumors

Dietary glycemic modulation through high-fat, low-carbohydrate diets, which induce a state of systemic ketosis and alter systemic metabolic signaling, have been incorporated into the clinical management of patients with neurological disease for more than a century. Mounting preclinical evidence supports the antitumor, proapoptotic, and antiangiogenic effects of disrupting glycolytic metabolism through dietary intervention. In recent years, interest in incorporating such novel therapeutic strategies in neuro-oncology has increased. To date, 3 published studies incorporating novel dietary therapies in oncology have been reported, including one phase I study in neuro-oncology, and have set the stage for further study in this field. In this article, we review the biochemical pathways, preclinical data, and early clinical translation of dietary interventions that modulate systemic glycolytic metabolism in the management of primary malignant brain tumors. We introduce the modified Atkins diet (MAD), a novel dietary alternative to the classic ketogenic diet, and discuss the critical issues facing future study.