Fast food purchasing and access to fast food restaurants: a multilevel analysis of VicLANES

Lukar E Thornton,Anne M Kavanagh,Rebecca J Bentley

doi:10.1186/1479-5868-6-28

Lukar E Thornton, Anne M Kavanagh + Show 1 more

Open Access

https://doi.org/10.1186/1479-5868-6-28

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Abstract

BackgroundWhile previous research on fast food access and purchasing has not found evidence of an association, these studies have had methodological problems including aggregation error, lack of specificity between the exposures and outcomes, and lack of adjustment for potential confounding. In this paper we attempt to address these methodological problems using data from the Victorian Lifestyle and Neighbourhood Environments Study (VicLANES) – a cross-sectional multilevel study conducted within metropolitan Melbourne, Australia in 2003.MethodsThe VicLANES data used in this analysis included 2547 participants from 49 census collector districts in metropolitan Melbourne, Australia. The outcome of interest was the total frequency of fast food purchased for consumption at home within the previous month (never, monthly and weekly) from five major fast food chains (Red Rooster, McDonalds, Kentucky Fried Chicken, Hungry Jacks and Pizza Hut). Three measures of fast food access were created: density and variety, defined as the number of fast food restaurants and the number of different fast food chains within 3 kilometres of road network distance respectively, and proximity defined as the road network distance to the closest fast food restaurant.Multilevel multinomial models were used to estimate the associations between fast food restaurant access and purchasing with never purchased as the reference category. Models were adjusted for confounders including determinants of demand (attitudes and tastes that influence food purchasing decisions) as well as individual and area socio-economic characteristics.ResultsPurchasing fast food on a monthly basis was related to the variety of fast food restaurants (odds ratio 1.13; 95% confidence interval 1.02 – 1.25) after adjusting for individual and area characteristics. Density and proximity were not found to be significant predictors of fast food purchasing after adjustment for individual socio-economic predictors.ConclusionAlthough we found an independent association between fast food purchasing and access to a wider variety of fast food restaurant, density and proximity were not significant predictors. The methods used in our study are an advance on previous analyses.

Highlights

While previous research on fast food access and purchasing has not found evidence of an association, these studies have had methodological problems including aggregation error, lack of specificity between the exposures and outcomes, and lack of adjustment for potential confounding
Purchasing fast food on a monthly basis was related to the variety of fast food restaurants after adjusting for individual and area characteristics
Conclusion: we found an independent association between fast food purchasing and access to a wider variety of fast food restaurant, density and proximity were not significant predictors

Summary

Introduction

While previous research on fast food access and purchasing has not found evidence of an association, these studies have had methodological problems including aggregation error, lack of specificity between the exposures and outcomes, and lack of adjustment for potential confounding. Evidence from the US showed that recent increases in the rates of fast food consumption [3,4] have coincided with growth in the number of fast food restaurants [5] Despite increases in both consumption and availability of fast food the potential link between the two remains largely unexplored with only Jeffery and colleagues in the U.S [6] and Turrell and Giskes [7] in Australia undertaking detailed investigation on this. Turrell and Giskes [7] assessed density and proximity using access measures created from the centroid of a study area which leads to 'aggregation error' [8] because the area-level variable may not be an accurate measure of individual exposure Both studies did not ask questions about the consumption or purchasing of particular fast food brands but defined the exposure variable with more specificity, resulting in a lack of congruence between exposure and outcome variables. Isolating an independent association between fast food access and purchasing requires methods that account for these potential confounders

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