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Studies of police shootings have typically focused upon demographic characteristics, police departmental characteristics, or more traditionally criminological characteristics such as crime rate. We use police shooting incidents to examine what role a less examined factor—proximity to a trauma center—has on whether the injured civilian dies or survives. We improve on previous work by estimating both distances and drive times along road networks. Findings from this study underscore the importance of prevention of police shootings, compared to after the fact responses, for reducing the numbers of homicides by police.

Over the last few decades, psychologists have developed precise quantitative models of human recall performance in visual working memory (VWM) tasks. However, these models are tailored to a particular class of artificial stimulus displays and simple feature reports from participants (e.g., the color or orientation of a simple object). Our work has two aims. The first is to build models that explain people’s memory errors in continuous report tasks with natural images. Here, we use image generation algorithms to generate continuously varying response alternatives that differ from the stimulus image in natural and complex ways, in order to capture the richness of people’s stored representations. The second aim is to determine whether models that do a good job of explaining memory errors with natural images also explain errors in the more heavily studied domain of artificial displays with simple items. We find that: (i) features taken from state-of-the-art deep encoders explain coarse-grained and some fine-grained aspects of trial-by-trial difficulty in natural images, while several reasonable baselines do not; and (ii) deep visual encoders could reproduce set-size effects but overall offered a poorer explanation of human data in the artificial domain. Together, our results suggest that people may rely on distinct cognitive systems or brain areas in artificial versus natural task domains. Moving forward, our approach offers a scalable way to build a more generalized understanding of VWM representations by combining recent advances in both AI and cognitive modeling.

The vision sciences literature contains a large diversity of experimental and theoretical approaches to the study of visual attention. We argue that this diversity arises, at least in part, from the field's inability to unify differing theoretical perspectives. In particular, the field has been hindered by a lack of a principled formal framework for simultaneously thinking about both optimal attentional processing and capacity-limited attentional processing, where capacity is limited in a general, task-independent manner. Here, we supply such a framework based on rate-distortion theory (RDT) and optimal lossy compression. Our approach defines Bayes-optimal performance when an upper limit on information processing rate is imposed. In this article, we compare Bayesian and RDT accounts in both uncued and cued visual search tasks. We start by highlighting a typical shortcoming of unlimited-capacity Bayesian models that is not shared by RDT models, namely, that they often overestimate task performance when information-processing demands are increased. Next, we reexamine data from two cued-search experiments that have previously been modeled as the result of unlimited-capacity Bayesian inference and demonstrate that they can just as easily be explained as the result of optimal lossy compression. To model cued visual search, we introduce the concept of a “conditional communication channel.” This simple extension generalizes the lossy-compression framework such that it can, in principle, predict optimal attentional-shift behavior in any kind of perceptual task, even when inputs to the model are raw sensory data such as image pixels. To demonstrate this idea's viability, we compare our idealized model of cued search, which operates on a simplified abstraction of the stimulus, to a deep neural network version that performs approximately optimal lossy compression on the real (pixel-level) experimental stimuli.

Although deep neural networks (DNNs) are state-of-the-art artificial intelligence systems, it is unclear what insights, if any, they provide about human intelligence. We address this issue in the domain of visual perception. After briefly describing DNNs, we provide an overview of recent results comparing human visual representations and performance with those of DNNs. In many cases, DNNs acquire visual representations and processing strategies that are very different from those used by people. We conjecture that there are at least two factors preventing them from serving as better psychological models. First, DNNs are currently trained with impoverished data, such as data lacking important visual cues to three-dimensional structure, data lacking multisensory statistical regularities, and data in which stimuli are unconnected to an observer’s actions and goals. Second, DNNs typically lack adaptations to capacity limits, such as attentional mechanisms, visual working memory, and compressed mental representations biased toward preserving task-relevant abstractions.

Efficient data compression is essential for capacity-limited systems, such as biological perception and perceptual memory. We hypothesize that the need for efficient compression shapes biological systems in many of the same ways that it shapes engineered systems. If true, then the tools that engineers use to analyze and design systems, namely rate-distortion theory (RDT), can profitably be used to understand human perception and memory. The first portion of this article discusses how three general principles for efficient data compression provide accounts for many important behavioral phenomena and experimental results. We also discuss how these principles are embodied in RDT. The second portion notes that exact RDT methods are computationally feasible only in low-dimensional stimulus spaces. To date, researchers have used deep neural networks to approximately implement RDT in high-dimensional spaces, but these implementations have been limited to tasks in which the sole goal is compression with respect to reconstruction error. Here, we introduce a new deep neural network architecture that approximately implements RDT. An important property of our architecture is that it is trained "end-to-end," operating on raw perceptual input (e.g., pixel values) rather than intermediate levels of abstraction, as is the case with most psychological models. The article's final portion conjectures on how efficient compression can occur in memory over time, thereby providing motivations for multiple memory systems operating at different time scales, and on how efficient compression may explain some attentional phenomena such as RTs in visual search. (PsycInfo Database Record (c) 2020 APA, all rights reserved).

The “resource-rational” approach is ambitious and worthwhile. A shortcoming of the proposed approach is that it fails to constrain what counts as a constraint. As a result, constraints used in different cognitive domains often have nothing in common. We describe an alternative framework that satisfies many of the desiderata of the resource-rational approach, but in a more disciplined manner.

This chapter focuses on a different conception of ecological space known as egohoods. It motivates the use of egohoods regarding the three features of routine activities theory: suitable targets, motivated offenders, and capable guardians. It discusses the spatial patterns of these three concepts and how egohoods as a geographic unit are well suited to capture their dynamic processes. It asks: what are the consequences of sociodemographic and business pattern changes in egohoods for the distribution of crime? Does the change in egohoods have similar implications for crime as does the change in meso-units such as neighborhoods, or microunits such as street segments? The chapter provides an empirical examination of these questions using data from the city of Los Angeles from 2000–2010 of robbery and burglary events.

Humans can easily describe, imagine, and, crucially, predict a wide variety of behaviors of liquids—splashing, squirting, gushing, sloshing, soaking, dripping, draining, trickling, pooling, and pouring—despite tremendous variability in their material and dynamical properties. Here we propose and test a computational model of how people perceive and predict these liquid dynamics, based on coarse approximate simulations of fluids as collections of interacting particles. Our model is analogous to a “game engine in the head”, drawing on techniques for interactive simulations (as in video games) that optimize for efficiency and natural appearance rather than physical accuracy. In two behavioral experiments, we found that the model accurately captured people’s predictions about how liquids flow among complex solid obstacles, and was significantly better than several alternatives based on simple heuristics and deep neural networks. Our model was also able to explain how people’s predictions varied as a function of the liquids’ properties (e.g., viscosity and stickiness). Together, the model and empirical results extend the recent proposal that human physical scene understanding for the dynamics of rigid, solid objects can be supported by approximate probabilistic simulation, to the more complex and unexplored domain of fluid dynamics., Author summary Although most people struggle to learn physics in school, every human brain is a remarkable “intuitive physicist” when it comes to the quick, unconscious judgments we make in interacting with the world. Almost effortlessly, and with surprisingly high quantitative accuracy, we can judge when a plate placed near the edge of a table might be at risk of falling, or how far a partially filled glass of water can be tipped before the water is in danger of spilling. What kinds of computations in the brain support these abilities? We suggest an answer based on probabilistic inference operating over particle-based simulations, the same class of approximation methods used in video games to simulate convincing real-time interactions between objects in a virtual environment. This hypothesis can potentially account for people’s quantitative, graded judgments in diverse and novel situations including a wide array of materials and physical properties, without positing a large number of separate systems or heuristics. Here, we build on previous evidence that a system of approximate probabilistic simulation supports judgments about rigid objects (e.g. judging the stability of towers of blocks, as in the game Jenga), and ask whether people can also make systematic and accurate predictions about flowing and splashing liquids, such as water or honey. We show that it is possible to capture people’s quantitative predictions using a computational model that approximates the true underlying fluid dynamics to varying degrees of coarseness, and find that people’s responses are most consistent with a very coarse approximation; while typical engineering applications might use tens or hundreds of thousands of particles to simulate a fluid, the brain might get by with roughly a hundred particles. Furthermore, we find that people consistently underestimate the potential energy of a splashing liquid in our virtual scenes, and that our model captures this behavior.

Human brains are finite, and thus have bounded capacity. An efficient strategy for a capacity-limited agent is to continuously adapt by dynamically reallocating capacity in a task-dependent manner. Here we study this strategy in the context of visual working memory (VWM). People use their VWM stores to remember visual information over seconds or minutes. However, their memory performances are often error-prone, presumably due to VWM capacity limits. We hypothesize that people attempt to be flexible and robust by strategically reallocating their limited VWM capacity based on two factors: (a) the statistical regularities (e.g., stimulus feature means and variances) of the to-be-remembered items, and (b) the requirements of the task that they are attempting to perform. The latter specifies, for example, which types of errors are costly versus irrelevant for task performance. These hypotheses are formalized within a normative computational modeling framework based on rate-distortion theory, an extension of conventional Bayesian approaches that uses information theory to study rate-limited (or capacity-limited) processes. Using images of plants that are naturalistic and precisely controlled, we carried out two sets of experiments. Experiment 1 found that when a stimulus dimension (the widths of plants' leaves) was assigned a distribution, subjects adapted their VWM performances based on this distribution. Experiment 2 found that when one stimulus dimension (e.g., leaf width) was relevant for distinguishing plant categories but another dimension (leaf angle) was irrelevant, subjects' responses in a memory task became relatively more sensitive to the relevant stimulus dimension. Together, these results illustrate the task-dependent robustness of VWM, thereby highlighting the dependence of memory on learning.

Background Physical activity is an essential element in reducing the prevalence of obesity, but much is unknown about the intensity and location of physical activity among youth—this is important because adolescent health behaviors are predictive of behaviors in adults. Purpose This study aims to identify the locations where youth moderate-to-vigorous physical activity (MVPA) occurs, and to examine how MVPA varies according to urbanicity (urban, suburban, rural). Methods Participants included adolescent students (N=380, aged 12–16 years) from Halifax, Nova Scotia. Locations of MVPA were measured using accelerometers and GPS data loggers for up to 7 days. Specialized software was developed to integrate and process the data. Frequencies of MVPA by location were determined, and differences in MVPA were assessed for association with urbanicity. Results Active commuting accounted for the largest proportion of time in MVPA among urban and suburban students. Rural students achieved most MVPA at school. Other residential locations, shopping centers, and green spaces accounted for a majority of the remaining MVPA. Minutes in MVPA varied significantly overall (196.6±163.8, 84.9±103.2, 81.7±98.2); at school (45.7±45.2, 18.6±28.0, 29.8±39.7); while commuting (110.3±107.1, 31.5±55.2, 19.5±39.7); and at other activity locations (19.7±27.1, 14.8±26.8, 12.0±22.1) and by urbanicity. Conclusions Findings reveal that the journeys between locations are as important as home and school settings in contributing to greater MVPA in adolescent youth. The relative importance of context as a contributor to MVPA varies with urbanicity. Combining actimetry and GPS data provides a precise link between physical activity measurements and contexts of the built environment.

Diet quality indices assess compliance with dietary guidelines and represent a measure of healthy dietary patterns. Few studies have compared different approaches to assessing diet quality in the same cohort. Our analysis was based on 972 participants of the British Diet and Nutrition Survey of people aged 65 y and older in 1994/1995 and who were followed-up for mortality status until 2008. Dietary intake was measured via a 4-d weighed food record. Three measures of diet quality were used: the Healthy Diet Score (HDS), the Recommended Food Score (RFS), and the Mediterranean Diet Score (MDS). HR for all-cause mortality were obtained using Cox regression adjusted for age, sex, energy intake, social class, region, smoking, physical activity, and BMI. After adjustment for confounders, the MDS was significantly associated with mortality [highest vs. lowest quartile; HR = 0.78 (95% CI = 0.62–0.98)]. Similarly, the RFS was also associated with mortality [HR = 0.67 (95 % CI = 0.52–0.86)]; however, there were no significant associations for the HDS [HR = 0.99 (95% CI = 0.79–1.24)]. The HDS was not a predictor of mortality is this population, whereas the RFS and the MDS were both associated with all-cause mortality. Simple measures of diet quality using food-based indicators can be useful predictors of longevity.

Summary Follow-up of a British national survey of older people found that in men, all-cause mortality was predicted by baseline plasma concentrations of phosphorus, albumin, creatinine and α1-antichymotrypsin, and food energy intake and in women by plasma alkaline phosphatase, creatinine, α1-antichymotrypsin, 25-hydroxy-vitamin D (marginally), and phosphorus intake. Introduction Predictive power, for all-cause mortality, of bone-related vitamin and mineral indices and intakes, measured at baseline (primary objective), was studied in the British National Diet and Nutrition Survey (community-living subset) of People Aged 65 Years and Over. A secondary objective was to identify cross-sectional relationships between indices at baseline to help explain mortality predictions. Methods Mortality status was recorded for 1,054 (mean age 76.6 ± 7.4 years, 49.0% female) participants from baseline survey in 1994/1995 until September 2008. Seventy-four per cent of male and 62% of female participants died. Cox proportional hazards models were used to relate baseline nutrient and risk marker estimates to subsequent survival. Results below 1.0 signified lower risk at greater nutrient (status or intake) values and vice versa. Results In both sexes, all-cause mortality was significantly predicted by body weight and mid-upper arm circumference. In men, it was predicted by baseline plasma concentrations (per SD) of: phosphorus (hazard ratio 1.18, 95% confidence interval (CI) = 1.06–1.30), albumin (hazard ratio 0.84, 95% CI = 0.74–0.94), creatinine (hazard ratio 1.20, 95% CI = 1.08–1.33) and α1-antichymotrypsin (hazard ratio 1.21, 95% CI = 1.11–1.33). In women, it was predicted by plasma albumin (hazard ratio 0.83, 95% CI = 0.72–0.96), alkaline phosphatase (hazard ratio 1.08, 95% CI = 1.01–1.16), creatinine (hazard ratio 1.37, 95% CI = 1.13–1.66), α1-antichymotrypsin (hazard ratio 1.27, 95% CI = 1.11–1.45) and marginally by 25-hydroxy-vitamin D (hazard ratio 0.87, 95% CI = 0.75–1.00). In men, it was predicted by dietary intake (per SD) of food energy; in women, by intake of phosphorus. Adjustment for plasma α1-antichymotrypsin or plasma creatinine reduced the significance of plasma phosphorus in men. Conclusion Mortality prediction by higher plasma phosphorus in older British men may imply impaired renal function and/or acute phase status. Further studies are needed on which associations are causal and modifiable.

Background: A low concentration of serum folate is associated with an increased risk of cardiovascular disease. Extracellular cysteine is involved in aging, cancer and cardiovascular disease. The relationship between serum folate and plasma cysteine is poorly understood. Therefore, we investigated this relationship in industry workers, whose health has economic implications. Methods: The concentration of serum folate was determined by the Access ImmunoAssay System Sanofi Pasteur. Plasma cysteine and homocysteine were measured by an ion-pair HPLC method. The concentrations of serum triglycerides were determined by an enzymatic colorimetric method. Results: We detected a positive correlation between the concentration of serum folate and plasma cysteine, whereas the concentration of serum folate was negatively correlated with plasma homocysteine and serum triglycerides. In a multiple regression analysis with adjustment for age, BMI and smoking, serum folate as the dependent variable exhibited a strong relationship with plasma cysteine, and a negative relationship with plasma homocysteine and serum triglycerides. Conclusion: We observed significant correlations between serum folate, plasma cysteine and serum triglyceride concentrations in industry workers, implying that folate may modulate key aspects of the body’s cysteine and lipid metabolism.

The predictive power, for total, vascular, cancer and respiratory mortality, of selected redox-modulatory (vitamin and mineral nutrient) indices measured at baseline, was studied in the British National Diet and Nutrition Survey (community-living subset) of people aged 65 years and over. Mortality status and its primary and underlying causes were recorded for 1054 (mean age 76·6 (sd 7·4) years and 49·0 % female) participants, from the baseline survey in 1994–5 until September 2008. During this interval, 74 % of the male and 62 % of the female participants died. Total mortality was significantly predicted by baseline plasma concentrations (per sd) of vitamin C (hazard ratio (HR) 0·81; 95 % CI 0·74, 0·88), α-carotene (HR 0·90; 95 % CI 0·81, 0·99), Se (HR 0·76; 95 % CI 0·69, 0·84), Zn (HR 0·79; 95 % CI 0·72, 0·87), Cu (HR 1·27; 95 % CI 1·14, 1·42) and Fe (HR 0·81; 95 % CI 0·74, 0·89). Total mortality was also significantly predicted by baseline dietary intakes (per sd) of food energy (HR 0·86; 95 % CI 0·79, 0·94), vitamin C (HR 0·88; 95 % CI 0·80, 0·94), carotenoids (HR 0·89; 95 % CI 0·83, 0·96), Zn (HR 0·89; 95 % CI 0·82, 0·96) and Cu (HR 0·91; 95 % CI 0·84, 1·00). Prediction patterns and significance for primary vascular, cancer and respiratory mortality differed in certain respects, but not fundamentally. Model adjustment for known disease or mortality risk predictors resulted in loss of significance for some of the indices; however, plasma Se and Zn, and food energy remained significant predictors. We conclude that total and primary vascular, cancer and respiratory mortality in older British people of both sexes is predicted by several biochemical indices of redox-modulatory nutrients, some of which may reflect the respondents' acute-phase status at baseline, whereas others may reflect the healthiness of their lifestyle.

There is variability in the association between dietary intake and health outcomes across different countries, especially among the elderly. We used the gold standard dietary assessment method, a weighed food record, to examine the association between dietary pattern and mortality in a representative sample of community dwelling participants from Great Britain aged 65 years and older. Dietary intake was recorded at baseline in 1017 elderly participants (520 men, 497 women, mean age 76.3±7.4 years). Exploratory factor analysis was performed to examine dietary patterns and participants were followed up over an average of 9.2 years for mortality. The factor analysis revealed four interpretable principal components accounting for approximately 9.8% of the total variance, with similar patterns across sex. A ‘Mediterranean-style’ dietary pattern explained the greatest proportion of the variance (3.7%), followed by ‘health-aware’ (2.2%), ‘traditional’ (2.0%) and ‘sweet and fat’ (1.9%) factors. There were a total of 683 deaths through follow-up. After adjustment for potential confounders, only the Mediterranean-style dietary pattern remained associated with mortality (highest vs lowest tertile; hazard ratio=0.82, 95% CI, 0.68–1.00). The benefits of the Mediterranean-style diet were only observed among women (hazard ratio=0.71, 95% CI 0.52–0.96) although in men the traditional diet was a risk factor for mortality (hazard ratio=1.30, 95% CI 1.00–1.71). Using a gold standard approach, our results confirm previous evidence that dietary patterns are important in longevity among the elderly.

Objective Our objective was to examine associations among plasma homocysteine concentrations (tHcy), the tHcy-cofactors (folate, vitamins B6 and B12), and multiple domains of cognitive performance, with statistical adjustment for possible confounds, including cardiovascular disease risk factors (CVD-RF) and cardiovascular disease (CVD). Methods Subjects were 812 participants (58% women) of the Maine-Syracuse study who were free of dementia and stroke. Employing a cross-sectional design and multiple regression analyses, fasting concentrations of tHcy and its vitamin cofactors (folate, B6, and B12) were related to multiple domains of cognitive performance. Results With adjustment for age, education, gender, ethnicity, and the vitamins, tHcy was inversely associated with visual-spatial organization, working memory, scanning-tracking, and abstract reasoning. The same results were found with adjustment for age, education, gender, ethnicity, CVD-RF, and CVD. Vitamin cofactors were positively related to cognitive performance, but with adjustment for CVD-RF and CVD, only vitamin B6 was related to multiple cognitive domains. Conclusions The inverse association of tHcy with multiple domains of cognitive functioning is not necessarily dependent on vitamin levels, vitamin deficiency, prevalent CVD risk factors, and manifest CVD. Serum folate, serum B12, and plasma B6 vitamin concentrations are positively associated with cognitive performance. Investigation of other possible mechanisms (e.g., tHcy neurotoxicity) mediating tHcy associations with cognitive performance is important, as are clinical trials examining the efficacy of folate, vitamin B6, and vitamin B12 for maintenance of cognitive functioning.

ObjectivesTo describe the selection and modification of an appropriate diet score to assess diet quality in early old age.Design and settingCross-sectional analyses of the Boyd Orr cohort – a long-term follow-up of men and women whose families took part in a survey of diet and health in pre-war Britain. Dietary data were obtained from a 113-item food-frequency questionnaire. A nine-item Healthy Diet Indicator (HDI) developed by Huijbregts and colleagues was identified from the literature and modified because some dietary variables were unavailable and to accord more closely with recommendations of the UK Committee on Medical Aspects of Food Policy.SubjectsIn total, 1475 traced, surviving cohort members aged 60 years and over.ResultsModification resulted in a 12-item Healthy Diet Score (HDS). We found that about half the variation in the HDS was explained by variation in the HDI (r = 0.71). There was, however, little misclassification of subjects (r = −0.57), red meat (r = −0.46), dietary fibre (r = 0.58), fruit and vegetables (r = 0.54) and percentage energy from carbohydrates (r = 0.51). Modifying existing items had greater impact on agreement between HDI and HDS than the addition of new items.ConclusionsThe selection and modification of diet scores is more complicated than often assumed. Furthermore, modest changes to an existing score can produce a score that is different from the original, and although it was not possible to test this issue, it may no longer predict subsequent health experience.

Vitamin C (ascorbate) is essential for hydroxylation of prolyl and lysyl residues in nascent collagen, the failure of which leads to connective tissue lesions of scurvy. Of the pyridinium-type cross-links in mature collagen, pyridinoline requires more hydroxylysyl residues than does deoxypyridinoline. Our study tested the hypothesis that pyridinoline:deoxypyridinoline ratios in urinary degradation products may vary with ascorbate status in man. These ratios were compared between British and Gambian prepubertal boys, mean age 8·3 years, and in Gambian boys between two seasons with contrasting ascorbate availability. The mean cross-links ratio in 216 British boys was 4·36 (sd 0·71), significantly greater (P7 weeks. If confirmed, the putative association between ascorbate and collagen cross-link ratios in man could become the basis for a functional test for adequacy of ascorbate status.

Background: Hyperhomocysteinemia (HHCY) is a risk factor for cardiovascular diseases (CVD). HHCY may interact with hypertension (HTEN) and an unfavorable cholesterol profile (UNFAVCHOL) to alter the risk of CVD. Objectives: To estimate the prevalences of HHCY (1) isolated and (2) in combination with UNFAVCHOL and/or HTEN in different age categories. To provide information that may improve the screening and treatment of subjects at risk of CVD. Design: Cross-sectional data on 12 541 men and 12 948 women aged 20 + y were used from nine European studies. Results: The prevalence of isolated HHCY was 8.5% in subjects aged 20-40 y, 4.7% in subjects aged 40-60 y and 5.9% in subjects aged over 60 y. When combining all age groups, 5.3% had isolated HHCY and an additional 5.6% had HHCY in combination with HTEN and/or UNFAVCHOL. The combinations of risk factors increased with age and, except for HHCY&UNFAVCHOL, were more prevalent than predicted by chance. Of the young subjects (20-40 y), 24% suffered from one or more of the investigated CVD risk factors. This figure was 75.1% in the old subjects (60 + years). Conclusions: A substantial number of subjects in selected European populations have HHCY (10.9%). In half of these cases, subjects suffer also from other CVD risk factors like UNFAVCHOL and HTEN. Older people in particular tend to have more than one risk factor. Healthcare professionals should be aware of this when screening and treating older people not only for the conventional CVD risk factors like UNFAVCHOL and HTEN but also HHCY, as this can easily be reduced through increased intake of folic acid via supplement or foods fortified with folic acid. © 2005 Nature Publishing Group All rights reserved.

A modified high-performance liquid chromatography (HPLC) method, based on Davidson and Sadowski [Meth. Enzymol. 282 (1997) 408], with fluorescence detection after zinc postcolumn reduction was developed and validated for the analysis of phylloquinone (vitamin K1) in plasma or serum samples. Compensation for procedural losses of vitamin K1 was made by the method of internal standardization using a proprietary vitamin K derivative. Increased sensitivity of detection by the use of a high-sensitivity Waters 440 fluorescence detector and optimized chromatography conditions increased the sensitivity to 4 fmol vitamin K1. The response was linear and free from interfering peaks and from baseline drift. It is therefore adequately sensitive for 0.25 ml or less of plasma sample. Long-term reproducibility of quality assurance (QA) samples was verified over a period of 4 months. The intraassay precision estimates of the QA samples within-run with mean vitamin K1 concentrations of 0.4, 1.4 and 3.4 nmol/l were 5.2% (n=6), 8.2% (n=6) and 3.0% (n=12), respectively, while interassay precision estimates between runs were 16% (n=22), 12% (n=21) and 8.1% (n=15), respectively. The assay accuracy was validated by comparing the results we obtained for 14 samples from the Vitamin K External Quality Assessment Scheme (KEQAS) with the consensus of the results from the other participating laboratories. Good agreement was obtained, with y=1.06x-0.09, R2=0.99. Validation also included linearity of response, absence of interference and confirmation of vitamin K1 peak purity.

Objective: Hyperhomocysteinemia and hypertriglyceridemia are independently associated with atherosclerotic disease. The process of atherogenesis involves inflammation and endothelial dysfunction. We tested whether concurrent acute hyperhomocysteinemia and mild hypertriglyceridemia increase the concentrations of circulatory cellular adhesion molecules in healthy subjects. Study Design and Methods: Twelve healthy volunteers aged 37.5 years (range, 25–51) participated in the present study. The concentrations of plasma total homocysteine (p-tHcy), serum triglycerides, circulatory cellular adhesion molecules (CAMs), and concentrations of nitrate were measured at 0 (fasting), 2, 4, and 6 h after loading with (1) methionine, (2) fat, (3) methionine + fat, and (4) water (control). Wash out period between each loading was ≥1 week. Results: Percent relative changes from baseline in the concentrations of p-tHcy, 2, 4, and 6 h after methionine and methionine + fat were significantly different from after water and fat loading. Changes in the concentrations of serum triglycerides 2 h after fat loading were significantly different from water loading, whereas methionine + fat loading caused a significant difference after 2, 4, and 6 h. We detected a synergistic increase in the triglyceride area response to methionine + fat loading. We detected also a significant difference in percent relative changes in the concentrations of P-selectin (PSEL) ( P = 0.02), E-selectin (ESEL) ( P = 0.003), and vascular cell adhesion molecule-1 (VCAM-1) ( P = 0.005) 6 h after methionine + fat loading as compared to water loading. There was an additive increase in the PSEL area response to methionine + fat loading. Furthermore, area response to VCAM was greater to methionine loading than water loading ( P = 0.01). A decrease in the concentration of NO 3 was more pronounced after methionine + fat loading and a significantly decreased area response of nitrate to methionine + fat loading was detected than to area response to water loading ( P = 0.002). Conclusion: Inflammatory activation of the endothelium takes place during concurrent transient hyperhomocysteinemia and mild hypertriglyceridemia.

To characterize nutritional differences between survey participants diagnosed with Type 2 diabetes; those without diabetes, and those with "undiagnosed diabetes" based on glycosylated haemoglobin (HbA(1c)).The 1994/5 British National Diet and Nutrition Survey, of people aged 65 years and over (mean age 78 years), included 73 respondents with diagnosed Type 2 diabetes [mean (sd) HbA(1c) = 7.06 (2.05)%], and 30 with "undiagnosed diabetes" (defined as HbA(1c)6.3%; mean (sd) HbA(1c) = 7.40 (1.66)%], among a representative sample of 1038 with anthropometry; 4-day weighed diet; blood and urine status measurements.The prevalence of Type 2 diabetes (diagnosed + undiagnosed) was 10%. In subjects without diagnosis of diabetes, those with HbA(1c)6.3% had on average a significantly higher body weight (73.6 vs. 67.9 kg), higher waist circumference (99.8 vs. 91.8 cm), higher body mass index (28.6 vs. 25.9 kg/m(2)) and higher white cell counts (7.64 vs. 7.09 x 10(9)/l), than those with mean HbA(1c)or = 6.3%. Diagnosed diabetic subjects had significantly higher energy-adjusted intakes of protein, fibre, vitamins and minerals than those not in this category (P0.01). In contrast, those with undiagnosed diabetes (HbA(1c)6.3%) were nutritionally "at risk", having low plasma concentrations of lycopene (0.13 vs. 0.24 micromol/l) and high density lipoprotein cholesterol (0.99 vs. 1.27 micromol/l) and a trend towards low vitamin C (24 vs. 36 micromol/l) which was significant (P0.01) for men. HbA(1c) was positively correlated with white cell count, plasma fasting triglycerides, plasma alkaline phosphatase and homocysteine (all P0.01 overall), being particularly striking amongst men.Among older British citizens, those with diagnosed diabetes had healthier nutritional profiles than those undiagnosed with high HbA(1c). Important health-promoting benefits are therefore predicted following early diagnosis and nutritional advice for people with Type 2 diabetes.

Objective: To examine zinc and vitamin A intake and status and associated dietary, socio-demographic, lifestyle and physiological factors in British young people. Design: National Diet and Nutrition Survey of young people aged 4–18 y. Setting: Great Britain, 1997. Subjects: Complete 7-day weighed dietary records were provided by 1520 participants, while 1193 provided blood samples. Results: A total of 13 and 11% of participants respectively reported low dietary intakes of zinc and vitamin A (retinol equivalents), relative to the UK lower reference nutrient intake. These percentages were not altered significantly by including contributions to intake from supplements, mainly containing vitamin A (as retinol). Likelihood of low zinc and/or vitamin A intake was more often associated with age, sex and likely under-reporting of food consumption than with other socio-demographic and lifestyle factors. Low zinc and vitamin A intakes were generally less likely in those with higher consumption of dairy foods (mainly milk). Zinc and vitamin A status (assessed by plasma zinc and retinol concentrations) were adequate in almost all participants. Plasma zinc concentration was not significantly associated with zinc intake. Plasma retinol concentration was correlated with vitamin A intake (overall r=0.17, P

Objective:To examine the prevalence and dietary, sociodemographic and lifestyle risk factors of low iron intake and poor iron status in British young people.Design:National Diet and Nutrition Survey of young people aged 4–18 years.Setting:Great Britain, 1997.Subjects:In total, 1699 young people provided 7-day weighed dietary records, of which 11% were excluded because the participant reported being unwell with eating habits affected. Blood was obtained from 1193 participants, with iron status indicated by haemoglobin, serum ferritin and transferrin saturation.Results:Iron intakes were generally adequate in most young people aged 4–18 years. However, low iron intakes (below the Lower Reference Nutrient Intake) occurred in 44% of adolescent girls (11–18 years), being less prevalent with high consumption of breakfast cereals. Low haemoglobin concentration (−1, 4–12 years; −1, 13+ years for girls and boys, respectively) was observed in 9% of children aged 4–6 years, pubertal boys (11–14 years) and older girls (15–18 years). Adolescent girls who were non-Caucasians or vegetarians had significantly poorer iron status than Caucasians or meat eaters, independent of other risk factors. The three iron status indices were correlated significantly with haem, but not non-haem, iron intake.Conclusions:Adolescent girls showed the highest prevalence of low iron intake and poor iron status, with the latter independently associated with non-Caucasian ethnicity and vegetarianism. Risk of poor iron status may be reduced by consuming (particularly lean red) meat or enhancers of non-haem iron absorption (e.g. fruit or fruit juice) in vegetarians.

Mild-to-moderate vitamin C depletion in weanling guinea-pigs affects pyridinoline:deoxypyridinoline (collagen cross-link) ratios in femur shaft and urine, attributed to impairment of hydroxylation of collagen lysine. We investigated: (1) whether the picture at two time points is compatible with progressive accumulation of abnormal collagen; (2) whether any changes are seen in skin, where little deoxypyridinoline occurs; (3) whether total food restriction has similar effects. Male weanling Dunkin–Hartley guinea-pigs were fed diets containing either 0·5 (vitamin C-restricted) or 160·0–320·0 (vitamin C-adequate) mg vitamin /. Two groups receiving the vitamin C-adequate diet received itad libitum. Two other groups received the vitamin C-adequate diet in a restricted amount, limited to that which permitted nearly the same growth rate as in the vitamin C-restricted groups. Animals were fed for 4 or 8 weeks; urine was collected, and vitamin C and collagen indices were measured. In the femur shaft, the hydroxyproline content per unit weight was unaffected by vitamin C restriction or by total food restriction. Deoxypyridinoline was increased and the pyridinoline:deoxypyridinoline ratio was decreased in vitamin C-restricted groups, but not in food-restricted groups. Changes in the value of the ratio were greater after 8 than after 4 weeks. Urine indices mirrored bone indices. In skin, the main effect of vitamin C restriction was to reduce hydroxyproline. Here, the cross-link ratios changed less markedly than in bone, and there was less deoxypyridinoline. We conclude that the picture at two time points is compatible with a progressive accumulation of pyridinoline-enriched collagen in vitamin C-deprived animals, that the picture in skin differs from that of bone and urine, and that cross-link changes are not produced by total food restriction.

Intake and sources of phylloquinone (vitamin K1) were examined according to socio-demographic and lifestyle factors in free-living British people aged 65 years and over, from the 1994-5 National Diet and Nutrition Survey. Complete 4-d weighed dietary records were obtained from 1152 participants living in private households. Using newly-available, mainly UK-specific food content data, the weighted geometric mean intake of phylloquinone was estimated at 65 (95 % CI 62, 67) microg/d for all participants, with higher intakes in men than in women (70 v. 61 microg/d respectively, P

Plasma phylloquinone (vitamin K1) concentration was examined according to season, socio-demographic and lifestyle factors and phylloquinone intake in a nationally representative sample of British people aged 65 years and over from the 1994–5 National Diet and Nutrition Survey. Values for both plasma phylloquinone concentration and phylloquinone intake were available from 1076 participants (561 men, 515 women). Eight hundred and thirty-four were living in private households, 242 in residential or nursing homes. Weighted geometric mean plasma phylloquinone concentrations were 0·36 (95 % CI 0·06, 2·01) and 0·24 (95 % CI 0·06, 0·96) nmol/l in free-living and institution samples respectively. Plasma phylloquinone concentrations did not generally differ between men and women, although values in free-living people were significantly lower during autumn and winter (October to March). Plasma phylloquinone concentration was not significantly associated with age. Plasma phylloquinone concentrations were positively correlated with phylloquinone intake in free-living men and women (r0·18 and 0·30 respectively, bothPP

Associations between oral contraceptive pill (OC) use and vitamin, mineral and lipid status were examined in 117 postmenarcheal 16-to-18-year-old British girls, from the 1997 National Diet and Nutrition Survey of young people aged 4 to 18 years. Thirty-nine were taking OCs at the time of blood, anthropometric and sociodemographic assessment, while seventy-eight were not. After adjusting for age, body mass index and smoking, OC use was significantly associated (P 12. Nutritional status indices that did not differ with OC use included plasma concentrations of vitamin C, α-tocopherol, pyridoxal phosphate, all-but-one iron status indices and zinc. In light of the observed associations, OC use should be taken into account when assessing nutritional status in adolescent girls of childbearing age.

Status indices for vitamins, iron and other minerals were compared in eighty-nine 12- and 13-year-old British girls according to their menarcheal status. The girls were selected at random to participate in the 1997 National Diet and Nutrition Survey of young people aged 4 to 18 years, and were either premenarcheal or postmenarcheal (i.e. had not or had experienced menarche respectively). After adjusting for age, body mass index, smoking status and corresponding nutrient intakes, mean values for iron status indices (e.g. haemoglobin, serum ferritin and plasma iron concentrations, mean cell volume, transferrin saturation and total iron-binding capacity), status indices of other minerals (e.g. zinc, copper, selenium and magnesium) and nine vitamins in forty-eight premenarcheal girls did not differ significantly from those of forty-one postmenarcheal counterparts (each P>0.05). Mean blood lead concentration was significantly lower in postmenarcheal compared with premenarcheal girls.

Plasma selenium (Se) concentrations were measured in 1134 British people aged 65 years and over, living in mainland Britain during 1994–1995. Eight hundred and eighty-three lived in the community (“free-living”), while the remainder lived in institutions (residential and nursing homes). The overall mean plasma Se concentrations was 0.90 μmol/l (inner 95% range 0.50–1.36 μmol/l). Free-living people had significantly higher values than counterparts living in institutions, and there was an overall inverse correlation with age. Plasma Se varied with season (lower from October to December than at other times of the year), while values were higher in southern Britain than in the North. Socio-economic associations also existed (lower plasma Se in people receiving state benefits or with poorer educational attainment), while smokers had lower values than non-smokers. Several indices of poor health status or of medicine use were correlated with lower plasma Se, which was also predicted by several biochemical or haematological indices of infection or inflammation. Plasma Se was strongly and directly correlated with plasma albumin, zinc, cholesterol, vitamin C, several carotenoids, alpha-tocopherol, pyridoxal phosphate, and with blood haemoglobin and several anthropometric indices. All relationships were independent of age and gender, and are consistent with the view that plasma Se levels are higher in fit and well-nourished elderly people and lower in those who are frail, poorly-nourished and unwell. Whole-blood glutathione peroxidase generally did not share these relationships, was only very weakly correlated with plasma Se, and appeared to be less useful as a status indicator in this population group.

Plasma total homocysteine (tHcy), cysteine and cysteinyl-glycine were measured in a representative sample of 922 young people aged 4–18 years, participating in the National Diet and Nutrition Survey in mainland Britain in 1997. Both tHcy and cysteine increased markedly with age; cysteinyl-glycine less so. Neither tHcy nor cysteine differed between genders; cysteinyl-glycine was higher in males. tHcy concentrations were lowest in the winter; cysteine and cysteinyl-glycine varied only slightly with season. In respondents aged >15 years, tHcy was higher in smokers, but in respondents aged 7–11 years, tHcy was higher in those whose mothers smoked. tHcy was inversely correlated with serum folate, serum vitamin B12and vitamin B6status, but neither cysteine nor cysteinyl-glycine shared these relationships. The relationships between tHcy and B-vitamin status indices ran parallel with those of the 65 years and over survey, but at much lower tHcy concentrations for any given B-vitamin concentration. Age-adjusted tHcy was not correlated with anthropometric indices, blood pressure, haematology, plasma creatinine, urea or cholesterol, but was directly correlated with fasting triacylglycerol. We conclude that disease-risk indices, like tHcy and perhaps cysteine, if established during early life, may be modulated by diet and lifestyle, thereby providing an opportunity for public health intervention.

To the Editor: An accumulating body of evidence has demonstrated the health benefit of certain behaviors, including moderate physical activity,1 not -smoking,2 low to moderate alcohol intake,3 and consumption of fruit and vegetables.4 Despite this, adherence to a healthy lifestyle pattern has decreased during the last 18 years.5 Because multiple health risk behaviors are known to cluster, the effect of combined health behavior on health outcomes may be important. This research may be helpful to inform policy-makers about the efficacy of multibehavior interventions as opposed to single-behavior interventions, but there is limited information about the effects of combined health behaviors on mortality in representative samples of older adults, which formed the rationale for the present study. Data were derived from the National Diet and Nutrition Survey (NDNS) of people living in the community aged 65 and older from mainland Britain.6 Ethical approval for the survey was obtained from the local research ethics committees for each of the 80 randomly-selected post code sectors included in the survey (20 per “wave”) and from the Ethics Committee of the Medical Research Council (MRC) Dunn Nutrition Unit. The survey was linked to National Health Service administrative mortality data up to September 2008. Self-reported physical activity, smoking, and alcohol use were recorded. Plasma vitamin C was used as a marker of plant food intake, with a value of 50 mU or greater used to indicate daily intake of at least five servings of fruit and vegetables, as previously defined.7 This measure was verified against estimated vitamin C intake from a 4-day weighed food record.6 A combined health behavior score was derived by giving 1 point for each of the following: nonsmoking, moderate alcohol consumption (1–21 units for men, 1–14 units for women), regular moderate to vigorous physical activity, and vitamin C (≥ 50 mU). Thus, the combined health behavior scores ranged from 0 to 4. The survey response rate was 85%; from the eligible sample of 2,172 participants, 72% provided full interview data and 59% provided full diet records. The present analysis consisted of 1,062 participants (539 men, 523 women, mean age, 76.5 ± 7.5, range 65–99) who consented to follow-up. Approximately 15.0% of the sample adhered to all four behaviors. Participants adhering to more healthy behaviors were younger, more likely to be female, and more highly educated and had better self-rated health. There were 714 all-cause deaths over an average of 9.2 years of follow-up. The results demonstrate a linear inverse association between the combined health behavior score and mortality risk, which persisted after adjustment for possible confounding factors (Table 1). All of the individual health behaviors were associated with lower risk of mortality: physical activity (multivariate-adjusted hazard ratio (HR)=0.83, 95% confidence interval (CI)=0.69–1.00), smoking (HR=0.73, 95% CI=0.59–0.90), moderate alcohol (HR=0.81, 95% CI=0.70–0.94), and vitamin C intake of 50 mU or greater (HR=0.88, 95% CI=0.74–1.05). None of the health behaviors individually was as powerful as the combined effects, which lowered the all-cause mortality rate 58%. When estimated dietary vitamin C intake was used instead of plasma vitamin C, the results were identical when using a cut-point of 40 mg/d to represent the U.K. recommended intake. Table 1 Cox Proportional Hazards Models for the Association Between Combined Health Behavior and Mortality over 9 Years of Follow-Up The present study demonstrated that adherence to healthy behaviors, including not smoking, moderate alcohol consumption, regular moderate to vigorous physical activity, and adequate vitamin C intake (a marker of fruit and vegetable consumption) was associated with lower risk of mortality in a representative sample of older participants from the United Kingdom. Approximately 15% of the sample met the criteria for all four healthy behaviors, which is comparable with a German cohort, in which 9% met the same criteria.8 Although a number of previous studies have examined associations between combined health behavior and disease end points, far less work has specifically considered the elderly population. In a cohort of elderly European men and women, adherence to the four key health behaviors lowered all-cause mortality 65%,9 which is similar to the results of the current study, which demonstrate a 51% lower risk after adjustment for possible confounders. In the Cardiovascular Health Study, the rate of incident diabetes mellitus was 35% lower for each additional low-risk lifestyle factor in participants aged 65 and older.10 Strengths of the present study include the nationally representative sample of community-dwelling adults, the prospective design, and the rigorous methods of outcome ascertainment. The exposure measures were based on self-report, which represents a limitation. In summary, healthy behaviors confer benefit for survival in older adults.

ObjectiveTo examine risk factors for poor iron status in British toddlers.DesignNational Diet and Nutrition Survey (NDNS) of children aged 1.5–4.5 years.SettingMainland Britain, 1992/93.SubjectsOf the 1859 children whose parents or guardians were interviewed, a weighed dietary intake was provided for 1675, and a blood sample obtained from 1003.ResultsMean haemoglobin (Hb) and ferritin levels were significantly lower in younger (1.5–2.5 years) than in older (3.5–4.5 years) children, with boys having significantly lower ferritin levels than girls. Poor iron status (Hb>110 g l−1, ferritin >10 μg l−1, or low values for both indices) was associated with lower socioeconomic and employment status. Iron status was directly associated with meat and fruit consumption and inversely with that of milk and milk products, after adjustment for age and gender. The latter association remained significant after further adjustment for sociodemographic variables, energy intake and body weight. Children consuming −1of milk and cream were less likely to consume foods in other groups, with those also consuming little meat, fish, fruit and nuts at greatest risk of poor iron status. Few associations were observed between poor iron status and individual nutrient intakes, and iron status was not associated with either iron intake or with consumption of a vegetarian diet.ConclusionsOverdependence on milk, where it displaces iron-rich or iron-enhancing foods, may put toddlers at increased risk of poor iron status. However, this becomes non-significant when moderate-to-high amounts of foods known to enhance iron status (e.g. meat and/or fruit) are also consumed. Milk consumption in this age group should ideally be part of a mixed and balanced diet including all food groups, and particularly lean meat (or other iron-rich or fortified foods) and fruit. This is particularly relevant for households of lower socioeconomic and employment status.

Summary This review describes and present the findings of a survey of the diet and nutrition of young people aged 4–18 years living in private households in the UK, carried out between January 1997 and January 1998. The National Diet and Nutrition Survey (NDNS) of young people aged 4–18 years forms part of the NDNS programme, which aims to provide a comprehensive, cross-sectional picture of the dietary habits, nutrient intakes and nutritional status of the British population by studying representative samples of defined age groups. The survey components included a detailed interview covering dietary habits, lifestyle and socio-demographic characteristics; a 7-day weighed dietary record; a 7-day physical activity diary; measurements of height, weight, mid-upper arm, waist and hip circumferences, and blood pressure; a blood sample for analysis of a range of nutritional status indices; a single urine sample; and an oral health interview and dental examination. A total of 1701 young people provided 7-day dietary records, representing a response rate of 64%. Results have been published in two volumes covering the diet and nutrition survey and the oral health survey. The reports present results for boys and girls separately in four age groups: 4–6 years; 7–10 years; 11–14 years and 15–18 years. Results are also presented by region and by socio-economic characteristics. This review summarises some of the main findings of the diet and nutrition survey, including: the proportion of young people who ate selected foods; energy and nutrient intakes compared with UK Dietary Reference Values; nutritional status; physical measurements; and physical activity.

Objectives: To determine the patterns and possible explanations for gender differences in food choices, nutrient intakes and status indices, especially for micronutrients, in a representative sample of older people living in Britain, who participated in the National Diet and Nutrition Survey of people aged 65 y and over during 1994–95. Design: The Survey procedures included a health-and-lifestyle interview, a four-day weighed diet record, anthropometric measurements and a fasting blood sample for biochemical indices. Setting: Eighty randomly-selected postcode sectors from mainland Britain. Subjects: Of 1556 older people not living in institutions who were interviewed, 80% agreed to provide a complete four-day diet record and 63% agreed to give a blood sample for status index measurements. Interventions: None. Main result: The most highly significant gender differences in food choices were that women ate more butter, full-fat milk and certain beverages, cakes, apples, pears and bananas, whereas men ate more eggs, sugar, certain meat products and drank more alcoholic drinks, especially beer and lager. When adjusted for energy intakes, the younger women (65–79 y) had higher intakes than the younger men, of fat, retinol, vitamin C and calcium. The older women (80+y) had higher intakes than older men, of fat and vitamin E, but lower intakes of protein, zinc and β-carotene. The younger women had better status indices than the younger men: for α- and β-carotenes, β-cryptoxanthin and vitamin C. Women had higher plasma concentrations of cholesterol and HDL cholesterol, phosphate and copper, but lower indices of iron and vitamin D status, than men. These gender differences in status were not altered by inclusion of the corresponding nutrient intakes in the model. Conclusions: There are gender differences in food choices, in energy and nutrient intakes and in nutritional blood status indices in older British people, especially those aged 65–79 y. Some of the status differences are attenuated in the age group of 80 y and older, whereas others are enhanced. The relationships between the quantity and type of foods or nutrients consumed, and nutrient status, are complex. With respect to suspected risk and protective factors for vascular disease, women aged 65–79 y had significantly better status for plasma α-and β-carotene, ascorbate, HDL-cholesterol and homocysteine; but, in contrast, they had lower blood haemoglobin concentrations and higher concentrations of total and non-HDL-cholesterol. Sponsorship: The British National Diet and Nutrition Survey series is funded by the Ministry of Agriculture, Fisheries and Food and the Department of Health, and this survey was conducted by Social and Community Planning Research in conjunction with MRC Human Nutrition Research (formerly MRC Dunn Nutritional Laboratory).

The aims of the National Diet and Nutrition Survey series are summarized, and the new National Diet and Nutrition Survey of people aged 65 years and over is explored, with particular emphasis on micronutrient intakes and status indices. Mean nutrient intakes were generally satisfactory for most micronutrients, but intakes of vitamin D, Mg, K and Cu were low. Intakes of vitamin D were far below the reference nutrient intake for people aged 65 years and over, and there was also biochemical evidence of vitamin D deficiency, for 8 % of free-living and 37 % of institution participants, attributed partly to limited exposure to sunlight. A substantial proportion of people living in institutions had inadequate biochemical status indices, notably for vitamin C, Fe and folate. Relationships between intake and status were close for vitamins. Mineral intakes did not correlate well with currently used status indices. Some intakes and indices, especially those of vitamin C, carotenoids, Na and K, were strongly correlated with socio-economic status and with north–south gradients in Britain. Future research challenges should address the functional and health significance of low intakes and sub-optimal biochemical indices for certain micronutrients, especially for people living in institutions; the shortcomings of mineral status indices especially as indicators of mineral intake; the social and geographical inequalities of micronutrient intakes and status, and why micronutrient status deteriorates with increasing age. The answers to these questions will help to define the characteristics of nutritional risk for older people in Britain, and to clarify future needs for education and intervention.

Objective:To compare vitamin B6status indices with each other and with potential confounding factors, in the datasets from two national British surveys and associated studies.Design:Vitamin B6status was measured by plasma pyridoxal phosphate (PLP) and plasma pyridoxic acid (PA) in both surveys, and also by erythrocyte aspartate aminotransferase activation coefficient (EAATAC) in one of the surveys. Plasma α1-antichymotrypsin was measured as an index of acute phase status; plasma creatinine was measured as an index of renal function; and plasma total alkaline phosphatase activity was measured as a proxy for PLP hydrolase activity.Setting:The survey of people aged 65 years and over was carried out in 80 postcode sectors across mainland Britain during 1994–95 and the survey of young people was carried out in 132 postcode sectors across mainland Britain during 1997.Subjects:Blood samples fromc. 1000 subjects of both sexes in each survey permitted measurements of plasma PLP and PA. There were also measurements of EAATAC in the young people's survey.Results:According to published limits of normality, only 5% or less of the young people had unacceptable vitamin B6status as measured by plasma PLP. About half had apparently unacceptable status by EAATAC, but this observation is difficult to interpret. The young people had considerably higher plasma concentrations of PLP and lower concentrations of PA than the older people. In both surveys, plasma PLP was strongly correlated with plasma PA and in the young persons’ survey it was also correlated, although much less strongly, with the basal activity and activation coefficient of aspartate aminotransferase. Both plasma PLP and EAATAC (but not PA nor basal aspartate aminotransferase activity) were influenced by acute phase status in young people, as indicated by significant correlations with α1-antichymotrypsin. In people aged 65 years and over, PA (but not PLP) was correlated with renal function, as indicated by its relation with plasma creatinine; however PLP (but not PA) was correlated with plasma alkaline phosphatase activity.Conclusions:Several potential confounders — acute phase reaction, kidney malfunction and hydrolase activity — may influence vitamin B6status indices, although differently for different indices and different age groups. Since older people have relatively poor vitamin B6status, which may have important health implications for them, more reliable vitamin B6status indices are needed.

Objectives: To examine seasonality of 25-hydroxyvitamin D (25OH-D) levels in British preschool children and the effect of vitamin D supplementation on this. Design: The National Diet and Nutrition Survey of children aged 1.5–4.5 y in Britain during 1992–3 measured dietary intakes and blood status indices, including those for vitamin D, during all four seasons. The present study addresses the seasonal dependence of the relation between vitamin D intake and status. Setting: 100 randomly selected postcode sectors throughout Britain, whose locations were classified as (a) Scotland; (b) Northern England; (c) Central, Wales, South+SW; (d) London+SE. Subjects: Of 1859 whose parents or guardians were interviewed, 1675 provided a weighed diet estimate, and blood vitamin D status (25OH-D) was measured in 756, with approximately equal numbers in each season. Results: Vitamin D status is highly dependent on season: moreover, the relation between vitamin D intake and status is also seasonally dependent, being strong in the winter and negligible in the summer. During the winter, those children who had relatively low 25OH-D concentrations generally were those not receiving vitamin D supplements. Vitamin D intakes and supplement use were lower in the north than in the south of Britain. Conclusions: For British preschool children, dietary vitamin D is of much greater importance in the winter than in the summer. There is evidence of regional inequality, with lesser use of supplements in the north. Supplements are needed in the winter, to achieve satisfactory vitamin D status and minimise the risk of rickets and of poor bone health, especially in high-risk groups. Sponsorship: This study was part of the National Diet and Nutrition Survey of Children Aged 1.5–4.5 y, which was funded jointly by the Ministry of Agriculture, Fisheries and Food and the Department of Health, and was conducted by the Social Survey Division of the Office of Population Censuses and Surveys (now the Office for National Statistics) and the MRC Dunn Nutritional Laboratory (now MRC Human Nutrition Research).

ObjectivesTo examine the relationship between cigarette smoking and a range of nutrient intakes and blood status indices in older people.DesignNational Diet and Nutrition Survey: cross-sectional survey of nationally representative sample of people aged 65 years and over.SettingMainland Britain during 1994/95.Subjects1191 people (619 male, 572 female) aged 65 years and over, of whom 920 were living in private households and 271 were living in institutions.ResultsCigarette smoking was inversely correlated with intakes of antioxidants and other micronutrients after adjustment for age, sex and domicile. Cigarette smoking was also inversely correlated with a number of antioxidant micronutrient status indices including plasma vitamin C and the carotenoids (but not vitamin E status indices), and with other micronutrient status indices, including plasma pyridoxal phosphate, red cell and serum folate, after adjustment for age, sex, domicile and the corresponding nutrient intake. Previous cigarette smoking or cigar/pipe smoking was not generally associated with lower nutrient intakes or status indices, however, both current and previous cigarette smoking was associated with increased concentrations of acute phase indicators. Further adjustment for total energy intake and/or sociodemographic, health and drug usage variables attenuated only a few of the associations observed.ConclusionOlder people who smoke cigarettes are at increased risk of suboptimal antioxidant and other micronutrient intakes and status, but the lower intakes found in cigarette smokers only partly explain their reduced blood indices.

We describe a procedure for the measurement of pyridoxal 5'-phosphate and of 4-pyridoxic acid in human plasma samples. It is based on the conversion of pyridoxal 5'-phosphate to 4-pyridoxic acid 5'-phosphate by cyanide in alkaline medium, followed by a high pressure liquid chromatographic separation, with fluorescence detection at acid pH. The assay is robust, sensitive, linear over a wide range, reproducible, and simple to perform. Samples stored at -80 degrees C are stable. Satisfactory agreement was obtained with results from the tyrosine decarboxylase-based assay for pyridoxal 5'-phosphate, in two other laboratories. Plasma samples from a National Survey of older British people were analyzed, and reference intervals for plasma pyridoxal 5'-phosphate intervals were derived. From the lower 2.5 percentile of the reference group, taken as the lower cut-off of the normal range, ca. 20% of elderly men and 11% of elderly women in the UK showed evidence of biochemical deficiency.

Objective:To describe the extent of use of medicines by older people living in Britain, and to explore relationships with vitamin status indices.Design:The National Diet and Nutrition Survey of people aged 65 years and over collected data from a British sample during 1994–95. The present study has made novel use of it, to relate medicine use with biochemical indices of vitamin status.Setting:Eighty postcode areas, selected randomly from mainland Britain.Subjects:1506 people, 65 years and over gave information about use of medication, and a 4-day weighed food record. Three-quarters gave blood for status indices.Results:78% of those living in the community and 93% of those in institutions were using medication. Certain vitamin status indices: plasma retinol, erythrocyte folate and riboflavin, paradoxically suggested better status in users than in non-users of antihypertensive, gastrointestinal, central nervous system, corticosteroid or diabetic drugs. There was evidence of a link with renal insufficiency, especially for plasma retinol, but neither this nor increased nutrient intake, acute phase effects or haemoconcentration could explain the paradoxical associations.Conclusions:Caution is needed in interpreting certain vitamin status indices, especially in older people who are extensively using medicines. New vitamin indices are needed, to avoid confounding interferences.

Objective To characterize relationships among blood pressure, pulse rate, vitamin C status and other protective and risk factors for older British people, from a national survey. Design A cross-sectional analysis of survey data. Setting A population study, representative of mainland Britain. Subjects Among 914 people of both sexes living in the community, 373 were taking blood-pressure-lowering drugs and were therefore excluded from the analyses. Interventions Completion of an interview on health, lifestyle and dietary habits, recording of a 4-day dietary record, anthropometry and taking of a blood sample to determine haematological and biochemical status. Main outcome measures Systolic and diastolic blood pressures, pulse rate, indices of micronutrient status including plasma ascorbate concentration, nutrient intake and haematology. Results Plasma ascorbate concentration was inversely correlated to systolic and diastolic blood pressures and pulse rate. Other covariates of blood pressure included age, sex, domicile, plasma retinol, fibrinogen and γ-tocopherol concentrations, erythrocyte count, prothrombin time and urine sodium: creatinine ratio. Covariates of pulse rate included sex, domicile, plasma fibrinogen and platelet count. Blood pressure was also correlated to intake of vitamin C. Conclusions Plasma ascorbate concentration and intake of vitamin C are covariates of blood pressure in older people living in Britain. New intervention studies are now needed, to test for possible causalities.

Vitamin C is essential for the hydroxylation of lysine in collagen. The resulting hydroxylysine residues, together with the precursor lysine residues, are then incorporated into the stable collagen cross-links: pyridinoline and deoxypyridinoline. A reduction in lysine hydroxylation, resulting from an inadequate supply of vitamin C, might decrease the ratio of the pyridinoline crosslinks to the deoxypyridinoline crosslinks. This hypothesis was tested in a guinea pig model, using a purified diet providing vitamin C in the following amounts: (a) 0.5 mg/day; (b) 1 mg/day; (c) 5 mg/day; (d) 0.25% w/v in the diet (providing 49 mg/day); (e) 1.0% w/v (providing 205 mg/day); or (f) 5.0% w/v (providing 1128 mg/day). Weanling male guinea pigs each received one of these diets for 46 days, after which their tissue vitamin C concentrations, and the concentrations of hydroxyproline, pyridinoline, and deoxypyridinoline in bone, and of creatinine, pyridinoline, and deoxypyridinoline in urine, were measured. The ratio of pyridinoline to deoxypyridinoline in bone collagen and in urinary collagen fragments decreased significantly as vitamin C depletion became more severe. Animals receiving the higher intakes of vitamin C grew more rapidly than did those receiving the lower intakes, but the relationship between vitamin C intake and the collagen crosslinks ratio remained highly significant, even after adjusting for intergroup differences in growth rates. Thus, the ratio between the two collagen crosslinks could provide a specific and sensitive functional index of vitamin C in animals and man. This is an important goal, in view of the need to be able to define optimum intakes of vitamin C.

Low intake of foods rich in vitamin C is associated with an increased risk of gastric cancer, and geographic variation in average vitamin C intake, therefore, could explain some of the wide international variation in gastric cancer rates. This multicentre study investigated the relationships between plasma levels of vitamin C, as an indicator of vitamin C intake, and gastric cancer rates, markers of gastritis and other socio-demographic variables. Fasting plasma samples from about 1,400 individuals from 9 centres in 7 countries worldwide were assayed for total vitamin C using a fluorometric assay. There was no association between average plasma vitamin C levels and either gastric cancer mortality or incidence rates in the populations studied. Therefore, variation in fasting plasma vitamin C levels, as an indicator of consumption of vitamin C, does not appear to explain any of the wide geographic variation in gastric cancer rates. Furthermore, there was no association between plasma vitamin C levels and Helicobacter pylori infection, low serum levels of pepsinogen A (as a marker of severe chronic atrophic gastritis) or the presence of DNA adducts in blood leukocyte DNA. Multivariate models showed that fasting plasma vitamin C levels were associated positively with female sex, higher levels of education, never having smoked and increasing height and negatively with number of cigarettes smoked per day and increasing weight. This suggests not only that gender and tobacco smoking, in particular, are important predictors of plasma vitamin C levels but also that their effects are consistent throughout the developed world.

During an epidemic outbreak of neuropathy in Cuba during 1992-1993, blood and urine samples were collected from 107 persons with confirmed neuropathy, from 106 control subjects without clinical abnormality who were broadly matched with the affected persons by age and domicile, and from 537 unmatched subjects, also free from clinical abnormality. The unmatched subjects lived in two locations in Cuba ; at each location they were drawn from two age ranges : 14-15-y-old secondary school students and 16-64-y-old adults. Measurements of urinary thiamine and blood transketolase and its activation with thiamine pyrophosphate were made. For the neuropathy subjects, these measurements were repeated after 3 wk of rehabilitation. All groups showed biochemical evidence of thiamine depletion affecting 30-70% of their members, which is a high prevalence. Severity of biochemical depletion was, however, no greater in the neuropathy subjects than in the control subjects (P > 0.05). However, it was greater in Pinar del Rio, where the incidence of disease was higher, than in the city of Havana, where less disease was seen. Although the majority of the affected subjects responded biochemically to a daily oral multivitamin supplement containing thiamine (P < 0.001), in some cases normal biochemical status was not achieved even after 3 wk of intensive treatment. In the affected group, thiamine status was inversely correlated with the amount of alcohol consumed (P = 0.007). Thiamine status at the outset was correlated with clinical outcome after treatment. Although neither thiamine depletion nor alcohol abuse were likely to have been the sole cause of the neuropathy epidemic, they may have been contributory factors. Thiamine supplementation or food fortification may therefore be necessary in Cuba.

The feasibility of studying ascorbic acid kinetics in man using stable isotope-labelled tracers and gas chromatographic (GC) separation followed by mass spectrometric (MS) quantitation was assessed. Preliminary studies with 13C-labelled material showed that although better precision at low levels could be achieved using the GC/combustion/MS technique, consideration of likely enrichments in a human study made the simpler GC/MS method just as suitable. On this basis, a small pilot study of the kinetics in man was carried out. The enrichment of the ascorbic acid in plasma was measured for a 24 h period after oral administration of 13C-labelled material. The results were fitted to a simple three-compartment model and rate constants and pool sizes were deduced. The results obtained are comparable to those obtained in other published studies, from which we conclude that the technique may be useful as a non-invasive method for the assessment of nutritional status in a variety of populations.