Identifying food deserts and swamps based on relative healthy food access: a spatio-temporal Bayesian approach.

Hui Luan,Jane Law,Matthew Quick

doi:10.1186/s12942-015-0030-8

Abstract

BackgroundObesity and other adverse health outcomes are influenced by individual- and neighbourhood-scale risk factors, including the food environment. At the small-area scale, past research has analysed spatial patterns of food environments for one time period, overlooking how food environments change over time. Further, past research has infrequently analysed relative healthy food access (RHFA), a measure that is more representative of food purchasing and consumption behaviours than absolute outlet density.MethodsThis research applies a Bayesian hierarchical model to analyse the spatio-temporal patterns of RHFA in the Region of Waterloo, Canada, from 2011 to 2014 at the small-area level. RHFA is calculated as the proportion of healthy food outlets (healthy outlets/healthy + unhealthy outlets) within 4-km from each small-area. This model measures spatial autocorrelation of RHFA, temporal trend of RHFA for the study region, and spatio-temporal trends of RHFA for small-areas.ResultsFor the study region, a significant decreasing trend in RHFA is observed (-0.024), suggesting that food swamps have become more prevalent during the study period. For small-areas, significant decreasing temporal trends in RHFA were observed for all small-areas. Specific small-areas located in south Waterloo, north Kitchener, and southeast Cambridge exhibited the steepest decreasing spatio-temporal trends and are classified as spatio-temporal food swamps.ConclusionsThis research demonstrates a Bayesian spatio-temporal modelling approach to analyse RHFA at the small-area scale. Results suggest that food swamps are more prevalent than food deserts in the Region of Waterloo. Analysing spatio-temporal trends of RHFA improves understanding of local food environment, highlighting specific small-areas where policies should be targeted to increase RHFA and reduce risk factors of adverse health outcomes such as obesity.

Highlights

Obesity and other adverse health outcomes are influenced by individual- and neighbourhood-scale risk factors, including the food environment
Model (2) and (3) were compared in Table 2 to identify the model that better represents the spatio-temporal variation of relative healthy food access (RHFA), which is the main goal of this study
A b δi Discussion Consistent with previous findings in the Canadian context, this paper reveals that food swamps are more prevalent than food deserts in the study region

Summary

Introduction

Obesity and other adverse health outcomes are influenced by individual- and neighbourhood-scale risk factors, including the food environment. Past research has infrequently analysed relative healthy food access (RHFA), a measure that is more representative of food purchasing and consumption behaviours than absolute outlet density. Past research has demonstrated that the food environment is an important factor in health outcomes. Measuring the food environment Various measures have been developed for assessing the food environment and have been summarized [8,9,10,11] and compared [12, 13] in extant literature While these measures can be categorized based on a number of different criteria (e.g., community or consumer nutrition environment1 [10]), one important distinction is between absolute and relative measures

Results

Discussion

Conclusion