Article Text

Socioeconomic variations in women’s diets: what is the role of perceptions of the local food environment?
1. V Inglis,
2. K Ball,
3. D Crawford
1. Centre for Physical Activity and Nutrition Research, Burwood, Victoria, Australia
1. Victoria Inglis, Food Standards Australia New Zealand, PO Box 7186, Canberra BC ACT 2610, Australia; vinglis{at}deakin.edu.au

## Abstract

Objectives: To test the contribution of perceived environmental factors (food availability, accessibility and affordability) to mediating socioeconomic variations in women’s fruit, vegetable and fast food consumption.

Methods: A community sample of 1580 women from 45 neighbourhoods provided survey data on their socioeconomic position (SEP) (education and income); diet (fruit, vegetable and fast food consumption); and the perceived availability of, access to and cost of healthy food in their local area.

Results: Once perceived environmental variables were considered, the associations between SEP and diet were weak and non-significant, suggesting that socioeconomic differences in diet were almost wholly explained by perceptions of food availability, accessibility and affordability.

Conclusions: Strategies to decrease socioeconomic inequalities in diet could involve promoting inexpensive ways to increase fruit and vegetable consumption, and ensuring that people of low SEP are aware that many healthy foods are available at relatively low cost. Future research should also confirm if perceptions match objective measures of food availability, accessibility and affordability, in order to address the real and/or perceived lack of healthy options in low SEP neighbourhoods.

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Compared with those of high socioeconomic position (SEP), individuals of low SEP have poorer diets according to a range of dietary indicators.16 For example, lower SEP individuals are more likely to consume diets high in fat, low in micronutrient density, and to have lower intakes of fruit and vegetables.710 As a result, studies repeatedly find that people of low SEP possess nutrient intakes and dietary patterns that increase risk of diet-related diseases.11 12

Even though SEP differences in diet are relatively well documented, the underlying causes of these differences are not well understood. Studies on the correlates of dietary behaviour have identified a range of individual, social and environmental influences on eating. However, the environmental influences (particularly food availability, accessibility and affordability) are under-researched, and existing studies show contradictory findings. Some studies have found that neighbourhood socioeconomic disadvantage is an independent risk factor for low fruit and vegetable intake or high fast food consumption.1315 However, other studies show that neighbourhood SEP is not associated with residents’ diets.16 17 When considering the environmental influences as mediators of SEP variations in diet, some studies show low SEP areas lack healthy eating options,18 19 whereas others show no difference between affluent and disadvantaged areas in availability, accessibility and cost.20 21 Australian research has found minimal socioeconomic differences in terms of access to or availability of healthy affordable foods22 and shopping infrastructure.23 Consistent with these findings, a recent qualitative study found that women from neighbourhoods across a range of SEP appeared generally satisfied with their local food environment and availability of healthy foods.24

The effects of socioeconomic disadvantage on diet could be mediated by socioeconomic differences in environmental factors such as food availability, accessibility and affordability. Few studies have directly tested this proposition. In one recent study that did, food environmental factors were not strong mediators of SEP variations in diet. However, the environmental factors assessed in that study were limited to two fairly crude indices: the number of large supermarkets and fruit and vegetable stores locally.25

This study aimed to investigate the relation between SEP, the perceived physical environment and women’s diets (in particular fruit, vegetable and fast food consumption). Specifically, aspects of the physical environment that may mediate the relation between SEP and diet were investigated. Women were the focus of this study since the determinants of women’s diets are likely to be different from those of men,26 and women remain largely responsible for domestic duties, including the provision of food.27

## METHODS

### Sample

The sample consisted of 1580 women involved in the Socioeconomic Status & Activity in Women (SESAW) study. Full details of the methods are described elsewhere.25 28 SESAW was restricted to a geographical area within approximately 25 km of the Melbourne central business district. Based on 2001 census data, the Australian Bureau of Statistics has assigned a SEIFA (Socioeconomic Index for Areas) score based on relative disadvantage to each suburb. All suburbs within the study area were ranked according to SEIFA score, and 45 suburbs (15 each from low, mid and high SEIFA areas) were randomly selected. An initial sample of 2400 women was randomly selected from the Australian electoral roll from all women of working age (18–65 years) within the 45 suburbs targeted.

Given discrepancy in response rates by SEP groups observed in health surveys,29 30 low and mid SEP suburbs were slightly oversampled relative to the high suburbs, by a ratio of 1.5:1.2:1. Hence the final sample drawn to receive the women’s diet survey consisted of 645 women from high SEP, 780 from mid SEP and 975 from low SEP suburbs. A total of 1136 women responded to the survey: 354 from high, 407 from mid and 375 from low SEP neighbourhoods. This response (50% overall, excluding from the denominator 127 women who had moved/were ineligible) is similar to those obtained in other recent mail-based surveys targeting women.31 The SESAW study focused on physical activity as well as diet. All participants completing a separate physical activity survey (which did not collect diet data) were asked if they were willing to complete a second survey, and those agreeing were posted the diet survey. This second phase of the study resulted in an additional 444 diet surveys (42% of those completing the original physical activity survey). Hence the final sample size for the present analyses was 1580. Owing to incomplete data, 252 women were excluded from analyses in table 2 (n = 1328); 204 women were excluded from analyses in table 3 (n = 1376); and 218 women were excluded from analyses in table 4 (n = 1362).

Table 2 Effects of adjusting for perceived environmental mediators on associations between women’s education level and likelihood of being a high fruit consumer in logistic regression models (n = 1328)
Table 3 Effects of adjusting for perceived environmental mediators on associations between women’s education level and likelihood of being a high vegetable consumer in logistic regression models (n = 1376)
Table 4 Effects of adjusting for perceived environmental mediators on associations between women’s income level and likelihood of being a frequent fast food consumer in logistic regression models (n = 1362)

### Procedures

#### What is already known on this subject

It is well documented that individuals of low socioeconomic position (SEP) have poorer diets according to a range of dietary indicators. However, the mechanisms underlying these socioeconomic differentials are not known.

#### What this study adds

The findings advance those of previous studies by showing that environmental factors such as perceived food availability, accessibility and affordability mediate the association between SEP and diet.

### Policy/programme implications

Public health strategies aimed at decreasing socioeconomic differences could involve promoting inexpensive ways to increase healthy foods such as fruit and vegetable consumption, and to ensure that people of low SEP are aware that many healthy foods are available at relatively low cost. Policies addressing poorer availability, accessibility and affordability of healthy foods in disadvantaged areas may also be required.

## Acknowledgments

VI is supported by a scholarship from the Victorian Health Promotion Foundation. KB and DC are each supported by an Australian National Health and Medical Research Council/National Heart Foundation Career Development Award. This project was partly funded by a grant from the National Heart Foundation, Reference number G 02M 0658, and by the Australian Research Council.

## Footnotes

• Competing interests: None.