The case of Montréal's missing food deserts: evaluation of accessibility to food supermarkets

Abstract

Background: Access to varied, healthy and inexpensive foods is an important public health concern that has been widely documented. Consequently, there is an increasing interest in identifying food deserts, that is, socially deprived areas within cities that have poor access to food retailers. In this paper we propose a methodology based on three measures of accessibility to supermarkets calculated using geographic information systems (GIS), and on exploratory multivariate statistical analysis (hierarchical cluster analysis), which we use to identify food deserts in Montréal.

Results: First, the use of three measures of accessibility to supermarkets is very helpful in identifying food deserts according to several dimensions: proximity (distance to the nearest supermarket), diversity (number of supermarkets within a distance of less than 1000 metres) and variety in terms of food and prices (average distance to the three closest different chain-name supermarkets). Next, the cluster analysis applied to the three measures of accessibility to supermarkets and to a social deprivation index demonstrates that there are very few problematic food deserts in Montréal. In fact, census tracts classified as socially deprived and with low accessibility to supermarkets are, on average, 816 metres away from the nearest supermarket and within 1.34 kilometres of three different chain-name supermarkets.

Conclusion: We conclude that food deserts do not represent a major problem in Montréal. Since geographic accessibility to healthy food is not a major issue in Montréal, prevention efforts should be directed toward the understanding of other mechanisms leading to an unhealthy diet, rather than attempting to promote an even spatial distribution of supermarkets.

Figure 1

Spatial distribution of low income population and social deprivation index on the Island of Montréal, 2001.

Figure 2

Spatial distribution of supermarket accessibility measures on the Island of Montréal, 2001.

Figure 3

Typology of census tracts on the basis of a social deprivation index and measures of accessibility to supermarkets on the Island of Montréal, 2001.

Figure 4

Boxplot of social deprivation and accessibility measures for classes of census tracts (see Figure 3).