Does exposure to the food environment differ by socioeconomic position? Comparing area-based and person-centred metrics in the Fenland Study, UK.

BACKGROUND: Retail food environments (foodscapes) are a recognised determinant of eating behaviours and may contribute to inequalities in diet. However, findings from studies measuring socioeconomic inequality in the foodscape have been mixed, which may be due to methodological differences. The aim of this cross-sectional study was to compare exposure to the foodscape by socioeconomic position using different measures, to test whether the presence, direction or amplitude of differences was sensitive to the choice of foodscape metric or socioeconomic indicator. METHODS: A sample of 10,429 adults aged 30-64 years with valid home address data were obtained from the Fenland Study, UK. Of this sample, 7270 participants also had valid work location data. The sample was linked to data on food outlets obtained from local government records. Foodscape metrics included count, density and proximity of takeaway outlets and supermarkets, and the percentage of takeaway outlets relative to all food outlets. Exposure metrics were area-based (lower super output areas), and person-centred (proximity to nearest; Euclidean and Network buffers at 800 m, 1 km, and 1 mile). Person-centred buffers were constructed using home and work locations. Socioeconomic status was measured at the area-level (2010 Index of Multiple Deprivation) and the individual-level (highest educational attainment; equivalised household income). Participants were classified into socioeconomic groups and average exposures estimated. Results were analysed using the statistical and percent differences between the highest and lowest socioeconomic groups. RESULTS: In area-based measures, the most deprived areas contained higher takeaway outlet densities (p < 0.001). However, in person-centred metrics lower socioeconomic status was associated with lower exposure to takeaway outlets and supermarkets (all home-based exposures p < 0.001) and socioeconomic differences were greatest at the smallest buffer sizes. Socioeconomic differences in exposure was similar for home and combined home and work measures. Measuring takeaway exposure as a percentage of all outlets reversed the socioeconomic differences; the lowest socioeconomic groups had a higher percentage of takeaway outlets compared to the middle and highest groups (p < 0.001). CONCLUSIONS: We compared approaches to measuring socioeconomic variation in the foodscape and found that the association was sensitive to the metric used. In particular, the direction of association varied between area- and person-centred measures and between absolute and relative outlet measures. Studies need to consider the most appropriate measure for the research question, and may need to consider multiple measures as a single measure may be context dependent.

Utilization of Away-From-Home Food Establishments, Dietary Approaches to Stop Hypertension Dietary Pattern, and Obesity.

INTRODUCTION: Eating meals away from home has been associated with the consumption of unhealthy foods and increased body weight. However, more rigorous assessment of the contribution of different types of away-from-home food establishments to overall diet quality and obesity is minimal. This study examined usage of these food establishments, accordance to the Dietary Approaches to Stop Hypertension (DASH) dietary pattern and obesity status in a nationally representative sample of adults in the United Kingdom. METHODS: A cross-sectional analysis of data from a national survey (N=2,083 aged ≥19 years, from 2008 to 2012) with dietary intake measured using a 4-day food diary, and height and weight measured objectively. Exposures included usage of (i.e., by proportion of energy) all away-from-home food establishments combined, and fast-food outlets, restaurants, and cafés separately. Outcomes included accordance with the DASH diet, and obesity status. Multivariable logistic regressions were conducted in 2016 to estimate associations between food establishments, diet quality, and obesity. RESULTS: People consuming a higher proportion of energy from any away-from-home food establishment had lower odds of DASH accordance (OR=0.45, 95% CI=0.31, 0.67) and increased odds of obesity (OR=1.48, 95% CI=1.10, 1.99). After adjustment, only use of fast-food outlets was significantly associated with lower odds of DASH accordance (OR=0.48, 95% CI=0.33, 0.69) and higher odds of obesity (OR=1.30, 95% CI=1.01, 1.69). CONCLUSIONS: Although a greater reliance on eating away-from-home is associated with less-healthy diets and obesity, dietary public health interventions that target these food establishments may be most effective if they focus on modifying the use of fast-food outlets.

Local food environment interventions to improve healthy food choice in adults: a systematic review and realist synthesis protocol.

INTRODUCTION: Local food environments have been linked with dietary intake and obesity in adults. However, overall evidence remains mixed with calls for increased theoretical and conceptual clarity related to how availability of neighbourhood food outlets, and within-outlet food options, influence food purchasing and consumption. The purpose of this work is to develop a programme theory of food availability, supported by empirical evidence from a range of local food environment interventions. METHODS AND ANALYSIS: A systematic search of the literature will be followed by duplicate screening and quality assessment (using the Effective Public Health Practice Project tool). Realist synthesis will then be conducted according to the Realist And Meta-narrative Evidence Syntheses: Evolving Standards (RAMESES) publication standards, including transparent appraisal, synthesis and drawing conclusions via consensus. DISSEMINATION: The final synthesis will propose an evidence-based programme theory of food availability, including evidence mapping to demonstrate contextual factors, pathways of influence and potential mechanisms. With the paucity of empirically supported programme theories used in current local food environment interventions to improve food availability, this synthesis may be used to understand how and why interventions work, and thus inform the development of theory-driven, evidence-based interventions to improve healthy food choice and future empirical work. TRIAL REGISTRATION NUMBER: PROSPERO CRD42014009808.

Area deprivation and the food environment over time: A repeated cross-sectional study on takeaway outlet density and supermarket presence in Norfolk, UK, 1990-2008.

Socioeconomic disparities in the food environment are known to exist but with little understanding of change over time. This study investigated the density of takeaway food outlets and presence of supermarkets in Norfolk, UK between 1990 and 2008. Data on food retail outlet locations were collected from telephone directories and aggregated within electoral wards. Supermarket presence was not associated with area deprivation over time. Takeaway food outlet density increased overall, and was significantly higher in more deprived areas at all time points; furthermore, socioeconomic disparities in takeaway food outlet density increased across the study period. These findings add to existing evidence and help assess the need for environmental interventions to reduce disparities in the prevalence of unhealthy food outlets.

Socio-economic dietary inequalities in UK adults: an updated picture of key food groups and nutrients from national surveillance data.

Socio-economic differences in diet are a potential contributor to health inequalities. The present study provides an up-to-date picture of socio-economic differences in diet in the UK, focusing on the consumption of three food groups and two nutrients of public health concern: fruit and vegetables; red and processed meat; oily fish; saturated fats; non-milk extrinsic sugars (NMES). We analysed data for 1491 adults (age ≥ 19 years) from the National Diet and Nutrition Survey 2008-2011. Socio-economic indicators were household income, occupational social class and highest educational qualification. Covariate-adjusted estimates for intakes of fruit and vegetables, red and processed meat, and both nutrients were estimated using general linear models. Covariate-adjusted OR for oily fish consumption were derived with logistic regression models. We observed consistent socio-economic gradients in the consumption of the three food groups as estimated by all the three indicators. Contrasting highest and lowest levels of each socio-economic indicator, we observed significant differences in intakes for the three food groups and NMES. Depending on the socio-economic indicator, highest socio-economic groups consumed up to 128 g/d more fruit and vegetables, 26 g/d less red and processed meat, and 2·6% points less NMES (P< 0·05 for all). Relative to lowest socio-economic groups, highest socio-economic groups were 2·4 to 4·0 times more likely to eat oily fish. No significant patterns in saturated fat consumption were apparent. In conclusion, socio-economic differences were identified in the consumption of food groups and one nutrient of public health importance. Aligning dietary intakes with public health guidance may require interventions specifically designed to reduce health inequalities.

Economic determinants of diet in older adults: systematic review.

BACKGROUND AND AIMS: Many economic factors are associated with diet, yet the evidence is generally cross-sectional. Older people are considered especially vulnerable to poor diets from negative changes to varied economic factors. This review extends current knowledge on known correlates to decipher actual economic determinants of diet in older adults. METHODS: Eight bibliometric databases were searched between May and December 2012, supplemented by hand-searches, with no restrictions on publication date or country. Longitudinal studies, or reviews, were eligible when examining diet as a function of change in an economic factor in non-institutionalised adults ≥60 years. Data were extracted using a standardised evidence table and quality assessed before narrative synthesis. RESULTS: We found nine original studies for inclusion, of which eight examined change from work to retirement and one evaluated a food price intervention. Designs were generally pre-post without controls and varying in follow-up. Studies reported mixed impact on food spending and/or food intake. Retirement was shown to both reduce and have no impact on food spending and to have either positive and negative, or positive and no impact on food intake. Subgroup differences were observed, especially between men and women. CONCLUSIONS: Despite ample research on economic correlates of older adults' diets, little is still known about actual economic determinants of diet in this population. Studies of retirement suggest divergent effects in some but not all older people. Robust high-quality longitudinal studies to decipher economic drivers of diet must be prioritised in research and policy as firm conclusions remain elusive.