Does the choice of neighbourhood supermarket access measure influence associations with individual-level fruit and vegetable consumption? A case study from Glasgow

Background
Previous studies have provided mixed evidence with regards to associations between food store access and dietary outcomes. This study examines the most commonly applied measures of locational access to assess whether associations between supermarket access and fruit and vegetable consumption are affected by the choice of access measure and scale.

Method
Supermarket location data from Glasgow, UK (n = 119), and fruit and vegetable intake data from the 'Health and Well-Being' Survey (n = 1041) were used to compare various measures of locational access. These exposure variables included proximity estimates (with different points-of-origin used to vary levels of aggregation) and density measures using three approaches (Euclidean and road network buffers and Kernel density estimation) at distances ranging from 0.4 km to 5 km. Further analysis was conducted to assess the impact of using smaller buffer sizes for individuals who did not own a car. Associations between these multiple access measures and fruit and vegetable consumption were estimated using linear regression models.

Results
Levels of spatial aggregation did not impact on the proximity estimates. Counts of supermarkets within Euclidean buffers were associated with fruit and vegetable consumption at 1 km, 2 km and 3 km, and for our road network buffers at 2 km, 3 km, and 4 km. Kernel density estimates provided the strongest associations and were significant at a distance of 2 km, 3 km, 4 km and 5 km. Presence of a supermarket within 0.4 km of road network distance from where people lived was positively associated with fruit consumption amongst those without a car (coef. 0.657; s.e. 0.247; p0.008).

Conclusions
The associations between locational access to supermarkets and individual-level dietary behaviour are sensitive to the method by which the food environment variable is captured. Care needs to be taken to ensure robust and conceptually appropriate measures of access are used and these should be grounded in a clear a priori reasoning.

Do food and physical activity environments vary between disadvantaged urban and rural areas? Findings from the READI study

Issues addressed: The presence or absence of amenities in local neighbourhood environments can either promote or restrict access to opportunities to engage in healthy and/or less healthy behaviours. Rurality is thought to constrain access to facilities and services. This study investigated whether the presence and density of environmental amenities related to physical activity and eating behaviours differs between socioeconomically disadvantaged urban and rural areas in Victoria, Australia.

Methods: We undertook cross-sectional analysis of environmental data collected in 2007-08 as part of the Resilience for Eating and Activity Despise Inequality (READI) study. These data were sourced and analysed for 40 urban and 40 rural socioeconomically disadvantaged areas. The variables examined were the presence, raw count, count/km², and count/'000 population of a range of environmental amenities (fast-food restaurants, all supermarkets (also separated by major chain and other supermarkets), greengrocers, playgrounds, gyms/leisure centres, public swimming pools and public open spaces).

Results: A greater proportion of urban areas had a fast-food restaurant and gym/leisure centre present while more rural areas contained a supermarket and public swimming pool. All amenities examined (with the exception of swimming pools) were more numerous per km² in urban areas, however rural areas had a greater number of all supermarkets, other supermarkets, playgrounds, swimming pools and public open area per '000 population.

Conclusion: Although opportunities to engage in healthy eating and physical activity exist in many rural areas, a lower density per km² suggests a greater travel distance may be required to reach these.

Does parkland influence walking? The relationship between area of parkland and walking trips in Melbourne, Australia

Background : Using two different measures of park area, at three buffer distances, we sought to investigate the ways in which park area and proximity to parks, are related to the frequency of walking (for all purposes) in Australian adults. Little previous research has been conducted in this area, and results of existing research have been mixed.

Methods : Residents of 50 urban areas in metropolitan Melbourne, Australia completed a physical activity survey (n = 2305). Respondents reported how often they walked for >=10 minutes in the previous month. Walking frequency was dichotomised to 'less than weekly' (less than 1/week) and 'at least weekly' (1/week or more). Using Geographic Information Systems, Euclidean buffers were created around each respondent's home at three distances: 400metres (m), 800 m and 1200 m. Total area of parkland in each person's buffer was calculated for the three buffers. Additionally, total area of 'larger parks', (park space >= park with Australian Rules Football oval (17,862 m2)), was calculated for each set of buffers. Area of park was categorised into tertiles for area of all parks, and area of larger parks (the lowest tertile was used as the reference category). Multilevel logistic regression, with individuals nested within areas, was used to estimate the effect of area of parkland on walking frequency.

Results : No statistically significant associations were found between walking frequency and park area (total and large parks) within 400 m of respondent's homes. For total park area within 800 m, the odds of walking at least weekly were lower for those in the mid (OR 0.65, 95% CI 0.46-0.91) and highest (OR 0.65, 95% CI 0.44-0.95) tertile of park area compared to those living in areas with the least amount of park area. Similar results were observed for total park area in the 1200 m buffers. When only larger parks were investigated, again more frequent walking was less likely when respondents had access to a greater amount of park area.

Conclusions : In this study we found that more park area in residential environments reduced the odds of walking more frequently. Other area characteristics such as street connectivity and destinations may underlay these associations by negatively correlating with park area.

Cohort profile : The resilience for eating and activity despite inequality (READI) study

The Resilience for Eating and Activity Despite Inequality (READI) cohort was established to address the following two key aims: to investigate the pathways (personal, social and structural) by which socio-economic disadvantage influences lifestyle choices associated with obesity risk (physical inactivity, poor dietary choices) and to explore mechanisms underlying ‘resilience’ to obesity risk in socio-economically disadvantaged women and children. A total of 4349 women aged 18–46 years and 685 children aged 5–12 years were recruited from 80 socio-economically disadvantaged urban and rural neighbourhoods of Victoria, Australia, and provided baseline (T1: 2007–08) measures of adiposity, physical activity, sedentary and dietary behaviours; socio-economic and demographic factors; and psychological, social and perceived environmental factors that might impact on obesity risk. Audits of the 80 neighbourhoods were undertaken at baseline to provide objective neighbourhood environmental data. Three-year follow-up data (2010–11) have recently been collected from 1912 women and 382 children. Investigators welcome enquiries regarding data access and collaboration.

Association between fast food purchasing and the local food environment

Objective: In this study, an instrument was created to measure the healthy and unhealthy characteristics of food environments and investigate associations between the whole of the food environment and fast food consumption.

Design and subjects: In consultation with other academic researchers in this field, food stores were categorised to either healthy or unhealthy and weighted (between +10 and −10) by their likely contribution to healthy/unhealthy eating practices. A healthy and unhealthy food environment score (FES) was created using these weightings. Using a cross-sectional study design, multilevel multinomial regression was used to estimate the effects of the whole food environment on the fast food purchasing habits of 2547 individuals.

Results: Respondents in areas with the highest tertile of the healthy FES had a lower likelihood of purchasing fast food both infrequently and frequently compared with respondents who never purchased, however only infrequent purchasing remained significant when simultaneously modelled with the unhealthy FES (odds ratio (OR) 0.52; 95% confidence interval (CI) 0.32–0.83). Although a lower likelihood of frequent fast food purchasing was also associated with living in the highest tertile of the unhealthy FES, no association remained once the healthy FES was included in the models. In our binary models, respondents living in areas with a higher unhealthy FES than healthy FES were more likely to purchase fast food infrequently (OR 1.35; 95% CI 1.00–1.82) however no association was found for frequent purchasing.

Conclusion: Our study provides some evidence to suggest that healthier food environments may discourage fast food purchasing.

Perceived quality and availability of fruit and vegetables are associated with perceptions of fruit and vegetable affordability among socio-economically disadvantaged women

Objective Perceptions that fruit and vegetables are expensive have been found to be associated with lower consumption of fruit and vegetables among disadvantaged women; however, the determinants of these perceptions are relatively unknown. The purpose of the current paper is to examine whether perceived availability and quality of fruit and vegetables, and social support for healthy eating, are associated with perceptions of fruit and vegetable affordability among women residing in disadvantaged neighbourhoods.

Design Cross-sectional self-report survey.

Setting The study was conducted in Melbourne, Australia.

Subjects An Australian sample of 4131 women, aged 18–45 years, residing in neighbourhoods ranked in the lowest Victorian tertile of relative disadvantage by the Australian Bureau of Statistics, an index that considers aspects of disadvantage such as residents’ income, education, motor vehicle access and employment.

Results Results showed that irrespective of education, income and other key covariates, women who perceived poor availability and quality of fruit and vegetables in their local neighbourhood were more likely to perceive fruit and vegetables as expensive.

Conclusions Our results suggest that perceptions of fruit and vegetable affordability are not driven exclusively by lack of financial or knowledge-related resources, but also by women's psychological response and interpretation of their local nutrition environment.

Duoscope

The ambiguous representation of spatial depth in Thornton Walker’s painting The Homage creates a peculiar sense in which the ‘whereness’ of depicted objects and atmosphere cannot be ascertained by, either perspectival convention or perceptual strategies. This visual-spatial ambiguity resonates with my interested in ‘broken’ stereography. Hence, ‘duoscopy’ refers to the limitations of binocular vision when the object of perception is itself duplicitous.

Structure retention in cross-linked poly(ethylene glycol) diacrylate hydrogel templated from a hexagonal lyotropic liquid crystal by controlling the surface tension

Retaining hexagonal lyotropic liquid crystal (LLC) structures in polymers after surfactant removal and drying is particularly challenging, as the surface tension existing during the drying processes tends to change the morphology. In this study, cross-linked poly(ethylene glycol) diacrylate (PEGDA) hydrogels were prepared in LLC hexagonal phases formed from a dodecyltrimethylammonium bromide (DTAB)/water system. The retention of the hexagonal LLC structures was examined by controlling the surface tension. Polarized light microscopy, X-ray diffraction and small angle X-ray scattering results indicate that the hexagonal LLC structure was successfully formed before polymerization and well retained after polymerization and after surfactant removal when the surface tension forces remained neutral. Controlling the surface tension during the drying process can retain the nanostructures templated from lyotropic liquid crystals which will result in the formation of materials with desired nanostructures.

Does the availability of snack foods in supermarkets vary internationally?

Background
Cross-country differences in dietary behaviours and obesity rates have been previously reported. Consumption of energy-dense snack foods and soft drinks are implicated as contributing to weight gain, however little is known about how the availability of these items within supermarkets varies internationally. This study assessed variations in the display of snack foods and soft drinks within a sample of supermarkets across eight countries.

Methods
Within-store audits were used to evaluate and compare the availability of potato chips (crisps), chocolate, confectionery and soft drinks. Displays measured included shelf length and the proportion of checkouts and end-of-aisle displays containing these products. Audits were conducted in a convenience sample of 170 supermarkets across eight developed nations (Australia, Canada, Denmark, Netherlands, New Zealand, Sweden, United Kingdom (UK), and United States of America (US)).

Results
The mean total aisle length of snack foods (adjusted for store size) was greatest in supermarkets from the UK (56.4 m) and lowest in New Zealand (21.7 m). When assessed by individual item, the greatest aisle length devoted to chips, chocolate and confectionery was found in UK supermarkets while the greatest aisle length dedicated to soft drinks was in Australian supermarkets. Only stores from the Netherlands (41%) had less than 70% of checkouts featuring displays of snack foods or soft drinks.

Conclusion
Whilst between-country variations were observed, overall results indicate high levels of snack food and soft drinks displays within supermarkets across the eight countries. Exposure to snack foods is largely unavoidable within supermarkets, increasing the likelihood of purchases and particularly those made impulsively.

Employment status, residential and workplace food environments: associations with women's eating behaviours

There remains a lack of consistent evidence linking food environments with eating behaviours. Studies to date have largely ignored the way different individuals interact with their local food environment and have primarily focussed on exposures within the residential neighbourhood without consideration of exposures around the workplace, for example. In this study we firstly examine whether associations between the residential food environment and eating behaviours differ by employment status and, secondly, whether food environments near employed women's workplaces are more strongly associated with dietary behaviours than food environments near home. Employment status did not modify the associations between residential food environments and eating behaviours, however results showed that having access to healthy foods near the workplace was associated with healthier food consumption. Policies focused on supportive environments should consider commercial areas as well as residential neighbourhoods.