Geospatial analysis of the urban food environment and diet quality of women living in Johannesburg, South Africa

B van der Westhuizen; K Naidoo; E Symington

B van der Westhuizen
K Naidoo
E Symington

Abstract

Objective: To assess the relationship between the urban food environment and diet quality in South Africa.
Design: This cross-sectional study assessed diet quality using Dietary Diversity Score (DDS) and the Minimum Dietary Diversity for Women (MDD-W) categories and the Rapid Eating Assessment for Participants – Shortened Version (REAP-S). The urban food environment was measured using geographic information systems (GIS) to map healthy and less healthy outlets within participants’ residential areas. The modified Retail Food Environment Index (mRFEI) and the Euclidean distances to food outlets were calculated.
Setting: Women in an urban suburb in Johannesburg, South Africa.
Subjects: A total of 427 generally healthy women were recruited between September 2022 and May 2023.
Outcome measured: Diet quality (DDS, MDD-W and REAP-S) and food environment (GIS, mRFEI and Euclidean distance).
Results: The mean DDS was 4.1 ± 1.4, with 64% of participants not achieving the MDD-W. The mean REAP-S score was 27.1 ± 3.3. Kernel density maps revealed that fast-food outlets were more densely clustered than grocery stores. The mean Euclidean distance from participants’ homes to the nearest grocery store was 464.4 metres, while fast-food outlets were 374.8 metres away. The mRFEI score of 31% indicated an obesogenic food environment. No association was found between diet quality and proximity to any food outlets.
Conclusion: The majority of the urban women showed poor diet quality; therefore, measures to improve this should include a combination of environmental and policy interventions. Recommendations include zoning regulations to limit fast-food outlet density near residential areas, health facilities and schools, and incentivising the establishment of grocery stores and fresh produce markets.

Keywords: urban food environment, South Africa, diet quality, modified Retail Food Environment Index (mRFEI); geographic
information systems (GIS)