Beyond proximity: how food quality in dollar and grocery stores influences health

Rising costs of groceries have prompted some United States (US) households to change their grocery shopping habits opting for dollar stores to lower household expenses. In previous work dollar stores have not been classified as a grocery store, limiting our understanding of how the dollar store associates with public health. Importantly, healthy food offerings such as fresh produce, whole grains, and lean proteins largely differ between traditional grocery stores and dollar stores. This public health study seeks to understand how the contrast in healthy food offerings associate with health outcomes across communities.

We used 2016-2020 data where traditional grocery store and dollar store locations across the contiguous US were geocoded and assigned as standard quality (SQ) and low-quality (LQ) respectively. Access to SQ and LQ was gleaned using ArcGIS network analysis of these geocoded points with census tracts of metro areas represented by the 2019 release of the Centers for Disease Control (CDC) 500 Cities Project (2016-2017 estimates). ArcGIS generalized linear regression models analyzed links between health outcomes from the CDC 500 Cities Project and key variables: proximity to SQ stores, proximity to LQ stores, and an aggregate of socioeconomic factors indexed by the 2016 CDC Social Vulnerability Index (SVI).

Results across and within most regions of the US demonstrated significant negative associations between proximity to SQ stores and adverse health outcomes such as obesity, diabetes, and high blood pressure. Conversely, proximity to LQ stores (i.e., dollar stores) demonstrated significant positive associations with all health outcomes across the US, even after accounting for SVI.

This study demonstrates the importance of dollar stores with food environment, an important component of food policy. Beyond recognizing dollar stores as grocery sources, these results emphasize the need to incorporate grocery quality into food environment research and policymaking.