Revisiting the modified Retail Food Environment Index (mRFEI): examining food access inequities over a decade in the United States

The modified Retail Food Environment Index (mRFEI) measures the percentage of healthy food retailers across U.S. census tracts. While widely used to assess food access disparities, mRFEI has not been updated since 2011, leaving a gap in capturing shifts in the food landscape. In this paper, we recalculate the mRFEI using the 2018–2019 Infogroup dataset and develop a web Geographic Information System tool to visualize its spatial pattern. Using the recalculated mRFEI, we evaluate the evolution of food access inequities by examining the relationships between the mRFEI and each theme of the community’s social vulnerability index (SVI) over a decade, adjusted for urbanicity. Our findings reveal that similarly to 2011, higher social vulnerability remains associated with lower access to healthy food retailers, particularly for socioeconomic status (b = − 0.246, 95% CI [− 0.287, − 0.206]), while minority status and language was no longer a significant predictor. However, these associations have weakened over time. The mRFEI gap between the most (bottom 10%) and the least (top 10%) vulnerable tracts (based on overall SVI) decreases by 2.176 (95% CI [1.638, 2.714]) over time. Similar reductions are observed for other SVI themes and when comparing the top and the bottom 25%, suggesting a narrowing food inequities. However, food acess gaps by urbanicity persist. Urban and suburban tracts consistently exhibit lower mRFEI than rural tracts, with the urban–rural gap widening over time. These diminishing yet persisting inequities highlight the need for continued policy efforts to narrow the food access gap.