In the United States the preferred method of obtaining dietary intake data is the 24-hour dietary recall, yet the measure of most interest is usual or long-term average daily intake, which is impossible to measure. Thus, usual dietary intake is assessed with considerable measurement error. Also, diet represents numerous foods, nutrients and other components, each of which have distinctive attributes. Sometimes, it is useful to examine intake of these components separately, but increasingly nutritionists are interested in exploring them collectively to capture overall dietary patterns. Consumption of these components varies widely: some are consumed daily by almost everyone on every day, while others are episodically consumed so that 24-hour recall data are zero-inflated. In addition, they are often correlated with each other. Finally, it is often preferable to analyze the amount of a dietary component relative to the amount of energy (calories) in a diet because dietary recommendations often vary with energy level. The quest to understand overall dietary patterns of usual intake has to this point reached a standstill. There are no statistical methods or models available to model such complex multivariate data with its measurement error and zero inflation. This paper proposes the first such model, and it proposes the first workable solution to fit such a model. After describing the model, we use survey-weighted MCMC computations to fit the model, with uncertainty estimation coming from balanced repeated replication.
The methodology is illustrated through an application to estimating the population distribution of the Healthy Eating Index-2005 (HEI-2005), a multi-component dietary quality index involving ratios of interrelated dietary components to energy, among children aged 2-8 in the United States. We pose a number of interesting questions about the HEI-2005 and provide answers that were not previously within the realm of possibility, and we indicate ways that our approach can be used to answer other questions of importance to nutritional science and public health.
Bayesian methods; Dietary assessment; Latent variables; Measurement error; Mixed models; Nutritional epidemiology; Nutritional surveillance; Zero-Inflated Data
We consider a Bayesian analysis using WinBUGS to estimate the distribution of usual intake for episodically consumed foods and energy (calories). The model uses measures of nutrition and energy intakes via a food frequency questionnaire (FFQ) along with repeated 24 hour recalls and adjusting covariates. In order to estimate the usual intake of the food, we phrase usual intake in terms of person-specific random effects, along with day-to-day variability in food and energy consumption. Three levels are incorporated in the model. The first level incorporates information about whether an individual in fact reported consumption of a particular food item. The second level incorporates the amount of intake from those individuals who reported consumption of the food, and the third level incorporates the energy intake. Estimates of posterior means of parameters and distributions of usual intakes are obtained by using Markov chain Monte Carlo calculations. This R function reports to users point estimates and credible intervals for parameters in the model, samples from their posterior distribution, samples from the distribution of usual intake and usual energy intake, trace plots of parameters and summary statistics of usual intake, usual energy intake and energy adjusted usual intake.
excess zero models; MCMC; nonlinear mixed models; R; R2WinBUGS; zero-inflation
Dietary assessment of episodically consumed foods gives rise to nonnegative data that have excess zeros and measurement error. Tooze et al. (2006, Journal of the American Dietetic Association 106, 1575–1587) describe a general statistical approach (National Cancer Institute method) for modeling such food intakes reported on two or more 24-hour recalls (24HRs) and demonstrate its use to estimate the distribution of the food’s usual intake in the general population. In this article, we propose an extension of this method to predict individual usual intake of such foods and to evaluate the relationships of usual intakes with health outcomes. Following the regression calibration approach for measurement error correction, individual usual intake is generally predicted as the conditional mean intake given 24HR-reported intake and other covariates in the health model. One feature of the proposed method is that additional covariates potentially related to usual intake may be used to increase the precision of estimates of usual intake and of diet-health outcome associations. Applying the method to data from the Eating at America’s Table Study, we quantify the increased precision obtained from including reported frequency of intake on a food frequency questionnaire (FFQ) as a covariate in the calibration model. We then demonstrate the method in evaluating the linear relationship between log blood mercury levels and fish intake in women by using data from the National Health and Nutrition Examination Survey, and show increased precision when including the FFQ information. Finally, we present simulation results evaluating the performance of the proposed method in this context.
Dietary measurement error; Dietary survey; Episodically consumed foods; Excess zero models; Food frequency questionnaire; Fish; Individual usual intake; Mercury; Nonlinear mixed models; Regression calibration; 24-hour recall
Food records, including 24-hour recalls and diet diaries, are considered to provide generally superior measures of long-term dietary intake relative to questionnaire-based methods. Despite the expense of processing food records, they are increasingly used as the main dietary measurement in nutritional epidemiology, in particular in sub-studies nested within prospective cohorts. Food records are, however, subject to excess reports of zero intake. Measurement error is a serious problem in nutritional epidemiology because of the lack of gold standard measurements and results in biased estimated diet–disease associations. In this paper, a 3-part measurement error model, which we call the never and episodic consumers (NEC) model, is outlined for food records. It allows for both real zeros, due to never consumers, and excess zeros, due to episodic consumers (EC). Repeated measurements are required for some study participants to fit the model. Simulation studies are used to compare the results from using the proposed model to correct for measurement error with the results from 3 alternative approaches: a crude approach using the mean of repeated food record measurements as the exposure, a linear regression calibration (RC) approach, and an EC model which does not allow real zeros. The crude approach results in badly attenuated odds ratio estimates, except in the unlikely situation in which a large number of repeat measurements is available for all participants. Where repeat measurements are available for all participants, the 3 correction methods perform equally well. However, when only a subset of the study population has repeat measurements, the NEC model appears to provide the best method for correcting for measurement error, with the 2 alternative correction methods, in particular the linear RC approach, resulting in greater bias and loss of coverage. The NEC model is extended to include adjustment for measurements from food frequency questionnaires, enabling better estimation of the proportion of never consumers when the number of repeat measurements is small. The methods are applied to 7-day diary measurements of alcohol intake in the EPIC-Norfolk study.
Excess zeros; Measurement error; Nutritional epidemiology; Repeated measures
Many foods are associated with chronic obstructive pulmonary disease (COPD) symptoms or lung function. Because foods are consumed together and nutrients may interact, dietary patterns are an alternative way of characterising diet. A study was undertaken to assess the relation between dietary patterns and newly diagnosed COPD in men.
Data were collected from a large prospective cohort of US men (Health Professionals Follow‐up Study). Using principal component analysis, two dietary patterns were identified: a prudent pattern (high intake of fruits, vegetables, fish and whole grain products) and a Western pattern (high intake of refined grains, cured and red meats, desserts and French fries). Dietary patterns were categorised into quintiles and Cox proportional hazards models were adjusted for age, smoking, pack‐years, (pack‐years)2, race/ethnicity, physician visits, US region, body mass index, physical activity, multivitamin use and energy intake.
Between 1986 and 1998, 111 self‐reported cases of newly diagnosed COPD were identified among 42 917 men. The prudent pattern was inversely associated with the risk of newly diagnosed COPD (RR for highest vs lowest quintile 0.50 (95% CI 0.25 to 0.98), p for trend = 0.02), and the Western pattern was positively associated with the risk of newly diagnosed COPD (RR for highest vs lowest quintile 4.56 (95% CI 1.95 to 10.69), p for trend <0.001).
In men, a diet rich in fruits, vegetables and fish may reduce the risk of COPD whereas a diet rich in refined grains, cured and red meats, desserts and French fries may increase the risk of COPD.
Many foods are associated with chronic obstructive pulmonary disease (COPD) symptoms or lung function. Because foods are consumed together and nutrients may interact, dietary patterns are an alternative way to characterize diet. Our objective was to assess the relation between dietary patterns and newly diagnosed COPD in men.
Data were collected from a large prospective cohort of US men (Health Professionals Follow-up Study). Using principal component analysis, two dietary patterns were identified: a prudent pattern (high intake of fruits, vegetables, fish and whole grain products) and a Western pattern (high intake of refined grains, cured and red meats, desserts and French fries). Dietary patterns were categorized into quintiles and Cox proportional hazards models were adjusted for age, smoking, pack-years, (pack-years)2, race/ethnicity, physician visits, US region, body mass index, physical activity, multivitamin use and energy intake.
Between 1986 and 1998, we identified 111 self-reported cases of newly diagnosed COPD among 42,917 men. The prudent pattern was inversely associated (RR for highest vs. lowest quintile [95%CI] = 0.50 [0.25–0.98], p for trend = 0.02) with the risk of newly diagnosed COPD. By contrast, the Western pattern was positively associated (RR for highest vs. lowest quintile [95%CI] = 4.56 [1.95–10.69], p for trend<0.001) with the risk of newly diagnosed COPD.
In men, a diet rich in fruits, vegetables and fish may reduce risk of COPD, whereas a diet rich in refined grains, cured and red meats, desserts and French fries may increase risk of COPD.
Adult; Aged; Asthma; epidemiology; Cohort Studies; Diet; statistics & numerical data; Humans; Male; Middle Aged; Prospective Studies; Pulmonary Disease; Chronic Obstructive; epidemiology; Risk Factors; United States; epidemiology; dietary pattern; principal component analysis; COPD; prospective cohort; men
To develop a method to validate an FFQ for reported intake of episodically consumed foods when the reference instrument measures short-term intake, and to apply the method in a large prospective cohort.
The FFQ was evaluated in a sub-study of cohort participants who, in addition to the questionnaire, were asked to complete two non-consecutive 24 h dietary recalls (24HR). FFQ-reported intakes of twenty-nine food groups were analysed using a two-part measurement error model that allows for nonconsumption on a given day, using 24HR as a reference instrument under the assumption that 24HR is unbiased for true intake at the individual level.
The National Institutes of Health–AARP Diet and Health Study, a cohort of 567 169 participants living in the USA and aged 50–71 years at baseline in 1995.
A sub-study of the cohort consisting of 2055 participants.
Estimated correlations of true and FFQ-reported energy-adjusted intakes were 0·5 or greater for most of the twenty-nine food groups evaluated, and estimated attenuation factors (a measure of bias in estimated diet–disease associations) were 0·4 or greater for most food groups.
The proposed methodology extends the class of foods and nutrients for which an FFQ can be evaluated in studies with short-term reference instruments. Although violations of the assumption that the 24HR is unbiased could be inflating some of the observed correlations and attenuation factors, results suggest that the FFQ is suitable for testing many, but not all, diet–disease hypotheses in a cohort of this size.
Diet; Food; Epidemiological methods; Questionnaires; Validation studies
To assess the adequacy of polyunsaturated fatty acid intake by rural Bangladeshi children 24–48 months of age in relation to their breastfeeding status.
Multi-stage sampling was used to select a representative sample of children 24–48 mo of age from two rural districts in Bangladesh (n=479). Two non-consecutive 24 h periods of dietary data were collected via 12 h daytime in-home observations and recall. Breast milk intake was estimated using test weighing. The National Cancer Institute method for episodically consumed foods was used to estimate distributions of usual food and nutrient intakes.
Based on the estimated intake distributions, more than 95% of the children had usual fat intakes less than 30% of total energy. Among 24–35 mo (younger) and 36–48 mo (older) children, respectively, 4% and 16% of breastfeeding children and 31% and 41% of non-breastfeeding children were estimated to consume less than 10% of total energy from fat. An estimated 80% of all children consumed less than 4% of total energy as linoleic acid, and 99% consumed less than 1% of energy as alpha-linolenic acid. Younger breastfeeding children had higher estimated average docosahexaenoic acid (DHA) intakes (0.04 g DHA/d) than their non-breastfeeding counterparts (0.01 g DHA/d; p = 0.0005). Both breastfeeding and non-breastfeeding older children had estimated mean DHA intakes of 0.02 g/d (p=0.74).
Rural Bangladeshi children 24–48 months of age, and especially those who have discontinued breastfeeding, may benefit from increased fat consumption.
breastfeeding; PUFA; DHA
The extension of life span by diet restriction in Drosophila has been argued to occur without limiting calories. Here we directly measure the calories assimilated by flies when maintained on full- and restricted-diets. We find that caloric intake is reduced on all diets that extend life span. Flies on low-yeast diet are long-lived and consume about half the calories of flies on high yeast diets, regardless of the energetic content of the diet itself. Since caloric intake correlates with yeast concentration and thus with the intake of every metabolite in this dietary component, it is premature to conclude for Drosophila that calories do not explain extension of life span.
diet restriction; calorie restriction; nutrition; aging; life span; Drosophila
Regression calibration has been described as a means of correcting effects of measurement error for normally distributed dietary variables. When foods are the items of interest, true distributions of intake are often positively skewed, may contain many zeroes, and are usually not described by well-known statistical distributions. The authors considered the validity of regression calibration assumptions where data are non-Gaussian. Such data (including many zeroes) were simulated, and use of the regression calibration algorithm was evaluated. An example used data from Adventist Health Study 2 (2002–2008). In this special situation, a linear calibration model does (as usual) at least approximately correct the parameter that captures the exposure-disease association in the “disease” model. Poor fit in the calibration model does not produce biased calibrated estimates when the “disease” model is linear, and it produces little bias in a nonlinear “disease” model if the model is approximately linear. Poor fit will adversely affect statistical power, but more complex linear calibration models can help here. The authors conclude that non-Gaussian data with many zeroes do not invalidate regression calibration. Irrespective of fit, linear regression calibration in this situation at least approximately corrects bias. More complex linear calibration equations that improve fit may increase power over that of uncalibrated regressions.
bias (epidemiology); foods; measurement error; power; regression calibration
The balance between the intake of animal and the intake of plant foods may influence renal vascular integrity as reflected by urinary albumin excretion.
We assessed cross-sectional associations between urinary albumin excretion and dietary patterns and intake of plant and animal foods.
At baseline, diet (food-frequency questionnaire) and the urinary albumin-to-creatinine ratio (ACR; spot urine collection) were measured in 5042 participants in the Multi-Ethnic Study of Atherosclerosis who were aged 45−84 y and were without clinical cardiovascular disease, diabetes, or macroalbuminuria (sex-adjusted ACR ≥ 250). We derived dietary patterns by principal components analysis. We also summed food groups to characterize plant food intake (fruit, fruit juice, vegetables, nuts, legumes, whole grains, and refined grains), animal food intake (red meat, processed meat, poultry, fish, high-fat dairy, and low-fat dairy), and nondairy animal food intake.
After adjustment for multiple demographic and lifestyle confounders, a dietary pattern characterized by high consumption of whole grains, fruit, vegetables, and low-fat dairy foods was associated with 20% lower ACR across quintiles (P for trend = 0.004). Neither total animal nor total plant food intake was associated with ACR. However, greater low-fat dairy consumption was associated with 13% lower ACR across quartiles (P for trend = 0.03). Total nondairy animal food consumption was associated with 11% higher ACR across quintiles (P for trend = 0.03).
A high intake of low-fat dairy foods and a dietary pattern rich in whole grains, fruit, and low-fat dairy foods were both associated with lower ACR. In contrast, collectively, nondairy animal food intake was positively associated with ACR.
Considerable interest has been shown in the ability of caloric restriction (CR) to improve multiple parameters of health and to extend lifespan. CR is the reduction of caloric intake - typically by 20 - 40% of ad libitum consumption - while maintaining adequate nutrient intake. Several alternatives to CR exist. CR combined with exercise (CE) consists of both decreased caloric intake and increased caloric expenditure. Alternate-day fasting (ADF) consists of two interchanging days; one day, subjects may consume food ad libitum (sometimes equaling twice the normal intake); on the other day, food is reduced or withheld altogether. Dietary restriction (DR) - restriction of one or more components of intake (typically macronutrients) with minimal to no reduction in total caloric intake - is another alternative to CR. Many religions incorporate one or more forms of food restriction. The following religious fasting periods are featured in this review: 1) Islamic Ramadan; 2) the three principal fasting periods of Greek Orthodox Christianity (Nativity, Lent, and the Assumption); and 3) the Biblical-based Daniel Fast. This review provides a summary of the current state of knowledge related to CR and DR. A specific section is provided that illustrates related work pertaining to religious forms of food restriction. Where available, studies involving both humans and animals are presented. The review includes suggestions for future research pertaining to the topics of discussion.
caloric restriction; dietary modification; oxidative stress; exercise
Mexico has seen a very steep increase in child obesity level. Little is known about caloric beverage intake in this country as well as all other countries outside a few high income countries. This study examines overall patterns and trends in all caloric beverages from two nationally representative surveys from Mexico.
The two nationally representative dietary intake surveys (1999 and 2006) from Mexico are used to study caloric beverage intake in 17, 215 children. The volume (ml) and caloric energy (kcal) contributed by all beverages consumed by the sample subjects were measured. Results are weighted to be nationally representative.
The trends from the dietary intake surveys showed very large increases in caloric beverages among pre-school and school children. The contribution of whole milk and sugar-sweetened juices was an important finding. Mexican pre-school children consumed 27.8% of their energy from caloric beverages in 2006 and school children consumed 20.7% of their energy from caloric beverages during the same time. The three major categories of beverage intake are whole milk, fruit juice with various sugar and water combinations and carbonated and noncarbonated sugared-beverages.
The Mexican government, greatly concerned about obesity, has identified the large increase in caloric beverages from whole milk, juices and soft drinks as a key target and is initiating major changes to address this problem. They have already used the data to shift 20 million persons in their welfare and feeding programs from whole to 1.5% fat milk and in a year will shift to nonfat milk. They are using these data to revise school beverage policies and national regulations and taxation policies related to an array of less healthful caloric beverages.
Our objective was to identify major dietary sources of whole grains and to describe the construction of a database of whole grain content of foods. Dietary information was collected with 7-d food records from men and women in the Baltimore Longitudinal Study of Aging, mean age 62.1 ± 16.0 years, who participated in the dietary assessment portion of the study (n = 1516), and estimates of whole grain intake were obtained from a newly developed database. The Pyramid Servings database and 1994–1996 Continuing Survey of Food Intakes by Individuals (CSFII) recipe ingredients database were then used to calculate both servings and gram weights of whole grain intakes. Mean intakes of whole grains, refined grains, and total grains, as well as frequency of intake for major whole grain food groups and whole grain content for each group, were calculated. Top contributors of whole grains were ready-to-eat breakfast cereals (made with whole grain as well as bran), hot breakfast cereals (made with whole grain), multi-grain bread, and whole wheat bread. While more research is needed to better understand the benefits of whole grains, the development of research tools, including databases to accurately assess whole grain intake, is a critical step in completing such research.
Whole grains; Wheat; Bran; Germ; Fiber; Database; Food composition
The American Academy of Pediatrics (AAP) recommends that children consume no more than 30% but no less than 20% of energy as dietary fat intake, and tills recommendation, is accompanied by suggestions that fat calories should be replaced by eating more grain products, fruits, vegetables, low fat datiy products, beans, lean meat, poultry, fish, and other protein rich foods. In comparing diets of girls meeting this AAP recommendation with girls who consumed diets higher in fat, we noted that girls meeting recommendations had diets that came closer to meeting other dietary recommendations for several food groups and had higher Intake of several key micronutrfents. Dietary fat was also associated with body fat and weight status. Children’s fat Intake was also related to mothers’ dietary fat intake, and nutrient Intake patterns were similar for mothers and daughters. Finally, mothers of girls consuming higher fat diets reported using more restriction and pressure to eat in feeding their daughters. These findings provide additional support for the AAP recommendation to limit total dietary fat Findings reveal that mothers’ use of controlling feeding practices are not effective in fostering healthier diets among cluldren, and that mothers’ own eating may be more influential than their attempts to control children’s intake.
Dietary fats; Nutrition assessment; Obesity; Child; Feeding behavior
To assess the adequacy of periconceptional intake of key micronutrients for perinatal health in relation to regular cereal consumption of pregnant women.
Design, setting, and subjects
Low-income pregnant women (n=596) in Pittsburgh, PA who enrolled in a cohort study <20 weeks gestation. These women reported usual dietary intake in the three months around conception on a food frequency questionnaire. Cereal consumers were women who reported consuming any dry cereal at least three times per week. High risk for nutrient inadequacy was defined as intake less than the Estimated Average Requirement.
About 31% of the women regularly consumed cereal. After adjusting for energy intake, race/ethnicity, marital status, breakfast consumption, and supplement use, cereal eaters had significantly higher intakes of folate, iron, zinc, calcium, fiber, and vitamins A, C, D, and E (all P<0.01) and were approximately 2 to 6 times as likely to have intakes in the highest third of the distribution for folate, iron, zinc, calcium, vitamins A and D, and fiber (all P<0.01) than non-cereal eaters. Cereal consumption was also associated with 65% to 90% reductions in risk of nutrient inadequacies compared with non-consumption (all P<0.01).
Encouraging cereal consumption may be a simple, safe, and inexpensive nutrition intervention that could optimize periconceptional intake for successful placental and fetal development.
cereal; diet; periconception; pregnancy
Both low dietary protein intake and inadequate distribution of protein over the three mealtimes have been reported in older Caucasian adults, but the association between protein intake at each meal and muscle mass has not been studied. The purpose of this study was to evaluate dietary protein intake and distribution by mealtimes, and to explore their association with appendicular skeletal muscle mass in apparently healthy older adults.
This was a cross-sectional pilot study that included 78 people over the age of 60 years. Caloric and protein intake were estimated on the basis of three nonconsecutive 24-hour diet recalls and appendicular skeletal muscle mass by dual-energy X-ray absorptiometry.
Men consumed 13.4 g of protein/day more than women (P < 0.05). The estimated value of dietary protein intake was 0.9 g/kg/day. In this sample, 28% of subjects did not cover 100% of the dietary reference intake for protein. Lower consumption of dietary protein was found at breakfast and dinnertime compared with the recommended amount of 25–30 g (P < 0.05). Also, the study observed that appendicular skeletal muscle mass in men and women who consumed <25 g of protein at each mealtime was different from that found in the group that consumed >25 g of protein at one, two, or three mealtimes.
While protein intake was higher than current recommendations, it failed to achieve the values reported as necessary to prevent sarcopenia. In addition, there was under-consumption of protein per mealtime, especially at breakfast and dinner.
dietary protein intake; older adults; appendicular skeletal muscle mass
Stomach and colorectal cancers are common cancers and leading causes of cancer deaths. Because the alimentary tract can interact directly with dietary components, stomach and colorectal cancer may be closely related to dietary intake. We systematically searched published literature written in English via PubMed by searching for terms related to stomach and colorectal cancer risk and dietary flavonoids up to June 30, 2012. Twenty-three studies out of 209 identified articles were finally selected for the analysis. Log point effect estimates and the corresponding standard errors were calculated using covariate-adjusted point effect estimates and 95%CIs from the selected studies. Total dietary flavonoid intake was not associated with a reduced risk of colorectal or stomach cancer [odds ratio (OR) (95%CI) = 1.00 (0.90-1.11) and 1.07 (0.70-1.61), respectively]. Among flavonoid subclasses, the intake of flavonols, flavan-3-ols, anthocyanidins, and proanthocyanidins showed a significant inverse association with colorectal cancer risk [OR (95%CI) = 0.71 (0.63-0.81), 0.88 (0.79-0.97), 0.68 (0.56-0.82), and 0.72 (0.61-0.85), respectively]. A significant association was found only between flavonols and stomach cancer risk based on a limited number of selected studies [OR (95%CI) = 0.68 (0.46-0.99)]. In the summary estimates from case-control studies, all flavonoid subclasses except flavones and flavanones were inversely associated with colorectal cancer risk, whereas neither total flavonoids nor any subclasses of flavonoids were associated with colorectal cancer risk in the summary estimates based on the cohort studies. The significant association between flavonoid subclasses and cancer risk might be closely related to bias derived from the case-control design. There was no clear evidence that dietary flavonoids are associated with reduced risk of stomach and colorectal cancer.
Flavonoids; Flavonols; Flavones; Flavanones; Flavan-3-ols; Anthocyanidins; Proanthocyanidins; Cancer risk; Meta-analysis
The U.S. Department of Agriculture’s (USDA) Healthy Eating Index-2005 (HEI-2005) is a tool to quantify and evaluate the quality of diet consumed by the US population. It comprises 12 components, expressed as ratios of a food group or nutrient to energy intake. The components are scored on a scale from 0 to M, where M is 5, 10 or 20. Ideally the HEI-2005 is calculated on the basis of the usual dietary intake of an individual. Intake data, collected via a 24-hour recall, are often available for only one day on each individual. In this paper, we examine how best to estimate a population’s mean usual HEI-2005 component and total scores when one day of dietary information is available for a sample of individuals from the population. Three methods are considered: the mean of individual scores, the score of the mean of individual ratios, and the score of the ratio of total food group or nutrient intake to total energy intake, which we call the population ratio. We investigate via computer simulation which method is the least biased. The simulations are based on statistical modeling of the distributions of intakes reported by 738 women participating in the Eating at America’s Table Study. The results show that overall the score of the population ratio is the preferred method. We therefore recommend that the quality of the US population’s diet be assessed and monitored using this method.
We examine two issues of importance in nutritional epidemiology: the relationship between dietary fat intake and breast cancer, and the comparison of different dietary assessment instruments, in our case the food frequency questionnaire (FFQ) and the multiple-day food record (FR). The data we use come from women participants in the control group of the Dietary Modification component of the Women’s Health Initiative (WHI) Clinical Trial. The difficulty with the analysis of this important data set is that it comes from a truncated sample, namely those women for whom fat intake as measured by the FFQ amounted to 32% or more of total calories. We describe methods that allow estimation of logistic regression parameters in such samples, and also allow comparison of different dietary instruments. Because likelihood approaches that specify the full multivariate distribution can be difficult to implement, we develop approximate methods for both our main problems that are simple to compute and have high efficiency. Application of these approximate methods to the WHI study reveals statistically significant fat and breast cancer relationships when a FR is the instrument used, and demonstrate a marginally significant advantage of the FR over the FFQ in the local power to detect such relationships.
Biased sampling; Breast cancer; Case–control studies; Comparison of instruments; Measurement error; Misspecified models; Nutritional epidemiology; Truncation; Women’s Health Initiative
Various foods have been shown to be associated with cognitive outcomes. As individual food items are not consumed in isolation, we examined the association between dietary patternsand cognitive function, with special attention to the role of education in this association.
Analyses were carried out on 4,693 stroke-free white European participants of the Whitehall II study. Two dietary patterns were determined using principal component analysis: a ‘whole food’ and a ‘processed food’ pattern. Cognitive function was assessed using a battery of 5 tests.
After adjustment for demographic, behavioral and health measures, higher intake of ‘whole food’ diet was associated with lower and high consumption of ‘processed food’ with higher odds of cognitive deficit. However, adjustment for education significantly attenuated most of these associations.
Education, through its role as a powerful confounder, shapes the relationship between dietary patterns and cognitive deficit in a healthy middle-aged UK cohort.
Nutrition; Cognitive functions; Population-based study; Education
Various foods have been shown to be associated with cognitive outcomes. As individual food items are not consumed in isolation, we examined the association between dietary patterns and cognitive function, with special attention to the role of education on this association.
Analyses were carried on 4693 stroke-free “white” European participants of the Whitehall II study. Two dietary patterns were determined using principal component analysis : a “Whole food” and a “Processed Food” pattern. Cognitive function was assessed using a battery of 5 tests.
After adjustment for demographic, behavioral and health measures, higher intake of “whole food” diet was associated with lower and high consumption of “processed food” with higher odds of cognitive deficit. However, adjustment for education significantly attenuated most of these associations.
Education, through its role as a powerful confounder, shapes the relationship between dietary patterns and cognitive deficit in a healthy middle-aged UK cohort.
Adult; Cognition Disorders; epidemiology; psychology; Cohort Studies; Diet; Education; Female; Food Habits; Great Britain; epidemiology; Health Behavior; Humans; Male; Middle Aged; Neuropsychological Tests; Questionnaires; Socioeconomic Factors; Vegetables; Epidemiology; Nutrition; Cognitive functions; Population-based study; Education
Current dietary therapy for long-chain 3-hydroxyacyl-CoA dehydrogenase (LCHAD) or trifunctional protein (TFP) deficiency consists of fasting avoidance, and limiting long-chain fatty acid (LCFA) intake. This study reports the relationship of dietary intake and metabolic control as measured by plasma acylcarnitine and organic acid profiles in 10 children with LCHAD or TFP deficiency followed for 1 year. Subjects consumed an average of 11% of caloric intake as dietary LCFA, 11% as MCT, 12% as protein, and 66% as carbohydrate. Plasma levels of hydroxypalmitoleic acid, hydroxyoleic, and hydroxylinoleic carnitine esters positively correlated with total LCFA intake and negatively correlated with MCT intake suggesting that as dietary intake of LCFA decreases and MCT intake increases, there is a corresponding decrease in plasma hydroxyacylcarnitines. There was no correlation between plasma acylcarnitines and level of carnitine supplementation. Dietary intake of fat-soluble vitamins E and K was deficient. Dietary intake and plasma levels of essential fatty acids, linoleic and linolenic acid, were deficient. On this dietary regimen, the majority of subjects were healthy with no episodes of metabolic decompensation. Our data suggest that an LCHAD or TFP-deficient patient should adhere to a diet providing age-appropriate protein and limited LCFA intake (10% of total energy) while providing 10–20% of energy as MCT and a daily multi-vitamin and mineral (MVM) supplement that includes all of the fat-soluble vitamins. The diet should be supplemented with vegetable oils as part of the 10% total LCFA intake to provide essential fatty acids.
Long-chain 3-hydroxyacyl-CoA dehydrogenase deficiency; Trifunctional protein deficiency; Long-chain fatty acids; Medium-chain triglycerides; Acylcarnitines; Essential fatty acids
To assess the nutritional adequacy of Seychellois children in relation to nutrients reported to be important for cognitive development.
Dietary intakes were assessed by 4 d weighed food diaries and analysed using dietary analysis software (WISP version 3·0; Tinuviel Software, UK). Individual nutrient intakes were adjusted to usual intakes and, in order to investigate adequacy, were compared with the UK Estimated Average Requirements for children aged 4–6 years.
Children 5 years old were followed up as part of the Seychelles Child Development Nutrition Study (SCDNS), located in the high-fish-consuming population of Mahé, Republic of Seychelles.
Analysis was carried out on a sample of 229 children (118 boys, 111 girls).
Children consumed a diet of which fortified cereal and milk products contributed the most to nutrient intakes. The majority (≥80 %) of children met requirements for several nutrients important for child development including Fe, folate and Se. Adjusted dietary intakes of Cu, Zn, iodine, niacin and vitamin A were below the Estimated Average Requirement or Recommended Nutrient Intake. Mean adjusted energy intakes (boys 4769 kJ/d (1139·84 kcal/d), girls 4759 kJ/d (1137·43 kcal/d)) were lower than the estimated energy requirement (boys 5104 kJ/d (1220 kcal/d), girls 5042 kJ/d (1205 kcal/d)) for 88% of boys and 86% of girls.
Nutrition was adequate for most children within the SCDNS cohort. Low intakes of some nutrients (including Zn, niacin and vitamin A) could reflect nutritional database inaccuracies, but may require further investigation. The study provides valuable information on the adequacy of intakes of nutrients which could affect the growth and development of Seychellois children.
Dietary intakes; Nutrient adequacy; Child nutrition; Cognitive development
Indices of overall dietary patterns are used in epidemiologic research to examine the relationship between nutrition and health. The objective of this study was to develop and validate an interpretable summary measure of dietary intake of whole plant foods (WPF-whole grains, vegetables, whole fruit, legumes, nuts, seeds) due to their similar nutritional characteristics and health effects. Six candidate WPF measures were calculated using data from subjects (age≥6y) participating in the 1999–2000 and 2001–2002 National Health and Nutrition Examination Survey (NHANES). Measures differed by the inclusion or exclusion of potatoes and whether they were expressed as total intake or as a proportion of energy (1000 kcal) or mass (kg) consumed. Both standard and non-truncated (allowed to vary proportionally with intake) Health Eating Index-2005 (HEI-2005) scores were calculated. Regression analysis examined associations between WPF and HEI-2005 measures, and between all diet measures and serum carotenoid concentration, serum lipids, fasting glucose, insulin, c-peptide and c-reactive protein. Mean total WPF intake was 3.6 cup/oz equivalents, or 1.7 cup/oz equivalents per 1000 kcal and per kg. The largest R2 between WPF and HEI-2005 measures was found for energy-adjusted WPF including potatoes and non-truncated HEI-2005 (R2 =0.50). All diet measures were positively related to serum carotenoids (p<0.001) and were similarly related with health indicators (R2 range from 0.003–0.16, p<0.045 for regressions indicating significant associations between WPF measures and health indicators). WPF measures are interpretable indicators of dietary intake that are significantly related to nutrition and health biomarkers, and may be of public health utility.
Human; Nutrition Indices; National Health and Nutrition Examination Survey; Food Plants; Biomarkers