Supermarket Transaction Records In Dietary Evaluation: the STRIDE study: validation against self-reported dietary intake.

OBJECTIVE: Scalable methods are required for population dietary monitoring. The Supermarket Transaction Records In Dietary Evaluation (STRIDE) study compares dietary estimates from supermarket transactions with an online FFQ. DESIGN: Participants were recruited in four waves, accounting for seasonal dietary variation. Purchases were collected for 1 year during and 1 year prior to the study. Bland-Altman agreement and limits of agreement (LoA) were calculated for energy, sugar, fat, saturated fat, protein and sodium (absolute and relative). SETTING: This study was partnered with a large UK retailer. PARTICIPANTS: Totally, 1788 participants from four UK regions were recruited from the retailer's loyalty card customer database, according to breadth and frequency of purchases. Six hundred and eighty-six participants were included for analysis. RESULTS: The analysis sample were mostly female (72 %), with a mean age of 56 years (sd 13). The ratio of purchases to intakes varied depending on amounts purchased and consumed; purchases under-estimated intakes for smaller amounts on average, but over-estimated for larger amounts. For absolute measures, the LoA across households were wide, for example, for energy intake of 2000 kcal, purchases could under- or over-estimate intake by a factor of 5; values could be between 400 kcal and 10000 kcal. LoA for relative (energy-adjusted) estimates were smaller, for example, for 14 % of total energy from saturated fat, purchase estimates may be between 7 % and 27 %. CONCLUSIONS: Agreement between purchases and intake was highly variable, strongest for smaller loyal households and for relative values. For some customers, relative nutrient purchases are a reasonable proxy for dietary composition indicating utility in population-level dietary research.

Objectively measuring the association between the built environment and physical activity: a systematic review and reporting framework.

BACKGROUND: Objective measures of built environment and physical activity provide the opportunity to directly compare their relationship across different populations and spatial contexts. This systematic review synthesises the current body of knowledge and knowledge gaps around the impact of objectively measured built environment metrics on physical activity levels in adults (≥ 18 years). Additionally, this review aims to address the need for improved quality of methodological reporting to evaluate studies and improve inter-study comparability though the creation of a reporting framework. METHODS: A systematic search of the literature was conducted following the PRISMA guidelines. After abstract and full-text screening, 94 studies were included in the final review. Results were synthesised using an association matrix to show overall association between built environment and physical activity variables. Finally, the new PERFORM ('Physical and Environmental Reporting Framework for Objectively Recorded Measures') checklist was created and applied to the included studies rating them on their reporting quality across four key areas: study design and characteristics, built environment exposures, physical activity metrics, and the association between built environment and physical activity. RESULTS: Studies came from 21 countries and ranged from two days to six years in duration. Accelerometers and using geographic information system (GIS) to define the spatial extent of exposure around a pre-defined geocoded location were the most popular tools to capture physical activity and built environment respectively. Ethnicity and socio-economic status of participants were generally poorly reported. Moderate-to-vigorous physical activity (MVPA) was the most common metric of physical activity used followed by walking. Commonly investigated elements of the built environment included walkability, access to parks and green space. Areas where there was a strong body of evidence for a positive or negative association between the built environment and physical activity were identified. The new PERFORM checklist was devised and poorly reported areas identified, included poor reporting of built environment data sources and poor justification of method choice. CONCLUSIONS: This systematic review highlights key gaps in studies objectively measuring the built environment and physical activity both in terms of the breadth and quality of reporting. Broadening the variety measures of the built environment and physical activity across different demographic groups and spatial areas will grow the body and quality of evidence around built environment effect on activity behaviour. Whilst following the PERFORM reporting guidance will ensure the high quality, reproducibility, and comparability of future research.

A systematic review of supermarket automated electronic sales data for population dietary surveillance.

CONTEXT: Most dietary assessment methods are limited by self-report biases, how long they take for participants to complete, and cost of time for dietitians to extract content. Electronically recorded, supermarket-obtained transactions are an objective measure of food purchases, with reduced bias and improved timeliness and scale. OBJECTIVE: The use, breadth, context, and utility of electronic purchase records for dietary research is assessed and discussed in this systematic review. DATA SOURCES: Four electronic databases (MEDLINE, EMBASE, PsycINFO, Global Health) were searched. Included studies used electronically recorded supermarket transactions to investigate the diet of healthy, free-living adults. DATA EXTRACTION: Searches identified 3422 articles, of which 145 full texts were retrieved and 72 met inclusion criteria. Study quality was assessed using the National Institutes of Health Quality Assessment Tool for Observational Cohort and Cross-Sectional Studies. DATA ANALYSIS: Purchase records were used in observational studies, policy evaluations, and experimental designs. Nutrition outcomes included dietary patterns, nutrients, and food category sales. Transactions were linked to nutrient data from retailers, commercial data sources, and national food composition databases. CONCLUSION: Electronic sales data have the potential to transform dietary assessment and worldwide understanding of dietary behavior. Validation studies are warranted to understand limits to agreement and extrapolation to individual-level diets. SYSTEMATIC REVIEW REGISTRATION: PROSPERO registration no. CRD42018103470.

Exploring the Geographic Variation in Fruit and Vegetable Purchasing Behaviour Using Supermarket Transaction Data.

The existence of dietary inequalities is well-known. Dietary behaviours are impacted by the food environment and are thus likely to follow a spatial pattern. Using 12 months of transaction records for around 50,000 'primary' supermarket loyalty card holders, this study explores fruit and vegetable purchasing at the neighbourhood level across the city of Leeds, England. Determinants of small-area-level fruit and vegetable purchasing were identified using multiple linear regression. Results show that fruit and vegetable purchasing is spatially clustered. Areas purchasing fewer fruit and vegetable portions typically had younger residents, were less affluent, and spent less per month with the retailer.

What is the cost of a healthy diet? Using diet data from the UK Women's Cohort Study.

BACKGROUND: A healthy diet is important to promote health and well-being while preventing chronic disease. However, the monetary cost of consuming such a diet can be a perceived barrier. This study will investigate the cost of consuming a range of dietary patterns. METHODS: A cross-sectional analysis, where cost of diet was assigned to dietary intakes recorded using a Food Frequency Questionnaire. A mean daily diet cost was calculated for seven data-driven dietary patterns. These dietary patterns were given a healthiness score according to how well they comply with the UK Department of Health's Eatwell Plate guidelines. This study involved ∼35 000 women recruited in the 1990s into the UK Women's Cohort Study. RESULTS: A significant positive association was observed between diet cost and healthiness of the diet (p for trend >0.001). The healthiest dietary pattern was double the price of the least healthy, £6.63/day and £3.29/day, respectively. Dietary diversity, described by the patterns, was also shown to be associated with increased cost. Those with higher education and a professional or managerial occupation were more likely to consume a healthier diet. CONCLUSIONS: A healthy diet is more expensive to the consumer than a less healthy one. In order to promote health through diet and reduce potential inequalities in health, it seems sensible that healthier food choices should be made more accessible to all.

Optimising the location of antenatal classes.

OBJECTIVES: To combine microsimulation and location-allocation techniques to determine antenatal class locations which minimise the distance travelled from home by potential users. DESIGN: Microsimulation modeling and location-allocation modeling. SETTING: City of Leeds, UK. PARTICIPANTS: Potential users of antenatal classes. METHODS: An individual-level microsimulation model was built to estimate the number of births for small areas by combining data from the UK Census 2001 and the Health Survey for England 2006. Using this model as a proxy for service demand, we then used a location-allocation model to optimize locations. FINDINGS: Different scenarios show the advantage of combining these methods to optimize (re)locating antenatal classes and therefore reduce inequalities in accessing services for pregnant women. KEY CONCLUSIONS: Use of these techniques should lead to better use of resources by allowing planners to identify optimal locations of antenatal classes which minimise women's travel. IMPLICATIONS FOR PRACTICE: These results are especially important for health-care planners tasked with the difficult issue of targeting scarce resources in a cost-efficient, but also effective or accessible, manner. (169 words).

Fast food and obesity: a spatial analysis in a large United Kingdom population of children aged 13-15.

BACKGROUND: The childhood obesity epidemic is a current public health priority in many countries, and the consumption of fast food has been associated with obesity. PURPOSE: This study aims to assess the relationship between fast-food consumption and obesity as well as the relationship between fast-food outlet access and consumption in a cohort of United Kingdom teenagers. METHODS: A weighted accessibility score of the number of fast-food outlets within a 1-km network buffer of the participant's residence at age 13 years was calculated. Geographically weighted regression was used to assess the relationships between fast-food consumption at age 13 years and weight status at ages 13 and 15 years, and separately between fast-food accessibility and consumption. Data were collected from 2004 to 2008. RESULTS: The consumption of fast food was associated with a higher BMI SD score (ß=0.08, 95% CI=0.03, 0.14); higher body fat percentage (ß=2.06, 95% CI=1.33, 2.79); and increased odds of being obese (OR=1.23, 95% CI=1.02, 1.49). All these relationships were stationary and did not vary over space in the study area. The relationship between the accessibility of outlets and consumption did vary over space, with some areas (more rural areas) showing that increased accessibility was associated with consumption, whereas in some urban areas increased accessibility was associated with lack of consumption. CONCLUSIONS: There is continued need for nutritional education regarding fast food, but public health interventions that place restrictions on the location of fast-food outlets may not uniformly decrease consumption.

Childhood consumption of fruit and vegetables across England: a study of 2306 6-7-year-olds in 2007.

The School Fruit and Vegetable Scheme (SFVS) provides children in government-run schools in England with a free piece of fruit or a vegetable each school day for the first 3 years of school. The present study examines the impact of the SFVS, in terms of its contribution towards the total daily intake of fruit and vegetables by children across England. Quantitative dietary data were collected from 2306 children in their third year of school, from 128 schools, using a 24 h food diary. The data were examined at different spatial scales, and variations in the impact of the scheme across areas with different socio-economic characteristics were analysed using a deprivation index and a geodemographic classification. The uptake of the SFVS and the total intake of fruit and vegetables by children varied across different parts of England. Participation in the SFVS was positively associated with fruit and vegetable consumption. That is, in any one area, those children who participated in the SFVS consumed more fruit and vegetables. However, children living in deprived areas still consumed less fruit and vegetables than children living in more advantaged areas: the mean daily frequency of fruit and vegetables consumed, and rates of consumption of fruit or vegetables five times or more per d, decreased as deprivation increased (r -0.860; P = 0.001; r -0.842; P = 0.002). So the SFVS does not eliminate the socio-economic gradient in fruit and vegetable consumption, but it does help to increase fruit and vegetable consumption in deprived (and affluent) areas.

Serial cross-sectional analysis of prevalence of overweight and obese children between 1998 and 2003 in Leeds, UK, using routinely measured data.

OBJECTIVE: To monitor growth trends in young children in order to ascertain success (or otherwise) in halting the rapid rise in childhood obesity prevalence, and to assess the suitability of using routinely measured data for this purpose. DESIGN: Retrospective serial cross-sectional analyses of the proportion of obese children (logistic regression) and BMI standard deviation score (linear regression/maps) were undertaken. BMI coverage was calculated as percentage of sample with data ('usual'), percentage of total births and percentage of census values. BMI was standardised for age and sex (British reference data set). SETTING: Metropolitan Leeds, UK. SUBJECTS: Children aged 3 to 6 years. Weight, height, sex, age and postcode data were collected from Primary Care Trust records. RESULTS: Data were collected on 42 396 children, of whom 13 020 (31 %) were excluded due to missing data/data problems. Seventy-two per cent of 3-year-olds and 92 % of 5-year-olds had data recorded ('usual' coverage). From 1998 to 2003 there was a significant increase in the proportion of obese children (4.5 % to 6.6 %; P < 0.001); children were 1.5 times more likely to be obese in 2003 than in 1998. CONCLUSIONS: Childhood obesity rose significantly between 1998 and 2003. Routinely measured data are an important means of monitoring population-level obesity trends, although more effort is required to reduce the quantity of data-entry errors, for relatively low marginal cost.

The geography of Fast Food outlets: a review.

The availability of food high in fat, salt and sugar through Fast Food (FF) or takeaway outlets, is implicated in the causal pathway for the obesity epidemic. This review aims to summarise this body of research and highlight areas for future work. Thirty three studies were found that had assessed the geography of these outlets. Fourteen studies showed a positive association between availability of FF outlets and increasing deprivation. Another 13 studies also included overweight or obesity data and showed conflicting results between obesity/overweight and FF outlet availability. There is some evidence that FF availability is associated with lower fruit and vegetable intake. There is potential for land use policies to have an influence on the location of new FF outlets. Further research should incorporate good quality data on FF consumption, weight and physical activity.

The design and validation of a spatial microsimulation model of obesogenic environments for children in Leeds, UK: SimObesity.

Obesogenic environments are a major explanation for the rapidly increasing prevalence in obesity. Investigating the relationship between obesity and obesogenic variables at the micro-level will increase our understanding about local differences in risk factors for obesity. SimObesity is a spatial microsimulation model designed to create micro-level estimates of obesogenic environment variables in the city of Leeds in the UK: consisting of a plethora of health, environment, and socio-economic variables. It combines individual micro-data from two national surveys with a coarse geography, with geographically finer scaled data from the 2001 UK Census, using a reweighting deterministic algorithm. This creates a synthetic population of individuals/households in Leeds with attributes from both the survey and census datasets. Logistic regression analyses identify suitable constraint variables to use. The model is validated using linear regression and equal variance t-tests. Height, weight, age, gender, and residential postcode data were collected on children aged 3-13 years in the Leeds metropolitan area, and obesity described as above the 98th centile for the British reference dataset. Geographically weighted regression is used to investigate the relationship between different obesogenic environments and childhood obesity. Validation shows that the small-area estimates were robust. The different obesogenic environments, as well as the parameter estimates from the corresponding local regression analyses, are mapped, all of which demonstrate non-stationary relationships. These results show that social capital and poverty are strongly associated with childhood obesity. This paper demonstrates a methodology to estimate health variables at the small-area level. The key to this technique is the choice of the model's input variables, which must be predictors for the output variables; this factor has not been stressed in other spatial microsimulation work. It also provides further evidence for the existence of obesogenic environments for children.

Study protocol: a cluster randomised controlled trial of a school based fruit and vegetable intervention - Project Tomato.

BACKGROUND: The School Fruit and Vegetable Scheme (SFVS) is an important public health intervention. The aim of this scheme is to provide a free piece of fruit and/or vegetable every day for children in Reception to Year 2. When children are no longer eligible for the scheme (from Year 3) their overall fruit and vegetable consumption decreases back to baseline levels. This proposed study aims to design a flexible multi-component intervention for schools to support the maintenance of fruit and vegetable consumption for Year 3 children who are no longer eligible for the scheme. METHOD: This study is a cluster randomised controlled trial of Year 2 classes from 54 primary schools across England. The schools will be randomly allocated into two groups to receive either an active intervention called Project Tomato, to support maintenance of fruit intake in Year 3 children, or a less active intervention (control group), consisting of a 5 A DAY booklet. Children's diets will be analysed using the Child And Diet Evaluation Tool (CADET), and height and weight measurements collected, at baseline (Year 2) and 18 month follow-up (Year 4). The primary outcome will be the ability of the intervention (Project Tomato) to maintain consumption of fruit and vegetable portions compared to the control group. DISCUSSION: A positive result will identify how fruit and vegetable consumption can be maintained in young children, and will be useful for policies supporting the SFVS. A negative result would be used to inform the research agenda and contribute to redefining future strategies for increasing children's fruit and vegetable consumption. TRIAL REGISTRATION: Medical Research Council Registry code G0501297.

Studying the infant feeding intentions of pregnant women experiencing material deprivation: methodology of the Looking at Infant Feeding Today (LIFT) study.

The Looking at Infant Feeding Today (LIFT) study examined the factors underlying the infant feeding choices of first-time mothers in the Leeds and Bradford areas of England experiencing material hardship, with a view to informing interventions aimed at increasing breastfeeding uptake amongst this group. This short report describes the novel methodology used to obtain data from a sample of pregnant women who are traditionally 'hard-to-reach' in deprived areas. This involved the use of trusted individuals such as midwives and multilingual health workers. A total of 449 women were approached; 441 (91.5%) agreed to participate and 303 returned completed questionnaires. Whilst 285 participants self-completed, 18 opted for interviewer assistance provided by a trained multilingual health worker. Feeding method up to 10 days after birth was obtained from the hospital records of 248 women (82.4% of eligible returns), and self-reported feeding method at six weeks was obtained from 273 women (90.7% of eligible returns). The study succeeded in obtaining data from a relatively deprived and hard-to-reach sample, with adequate numbers of participants in the subgroups of interest (teenage, left full time education age 16 or younger, household receiving income support or job seekers allowance, Asian or African-Caribbean).

Measuring the school impact on child obesity.

This article explores the impact that schools have on their pupils' obesity and so identify those where targeted input is most needed. A modelling process was developed using data that had been collected over 2 years on a socio-economically and ethnically representative sample of 2367 school pupils aged 5 and 9 years old attending 35 Leeds primary schools. The three steps in the model involved calculating the "Observed" level of obesity for each school using mean body mass index standard deviation (BMI SDS); adjusting this using ethnicity and census-derived deprivation data to calculate the "Expected" level; and calculating the "Value Added" by each school from differences in obesity at school entry and transfer. We found there was significant variance between the schools in terms of mean BMI SDS (range -0.07 to +0.78). Residential deprivation score and ethnicity accounted for only a small proportion of the variation. Expected levels of obesity therefore differed little from the Observed, but the Value Added step produced very different rankings. As such, there is variation between schools in terms of their levels of obesity. Our modelling process allowed us to identify schools whose levels differed from that expected given the socio-demographic make up of the pupils attending. The Value Added step suggests that there may be a significant school effect. If this is validated in extended studies, the methodology could allow for exploration of mechanisms contributing to the school effect, and identify schools with the highest unexpected prevalence. Resources could then be targeted towards those schools in greatest need.