Cluster-randomized controlled trial of a mobile produce market designed to address diet and food insecurity in underserved communities.

backgroundVeggie Van (VV) is a multi-level mobile produce market intervention that increased fruit and vegetable (F&V) consumption in lower-income communities in an efficacy study. The aim of this study was to understand the impact of the VV intervention delivered by multiple community partners on food security and diet-related behaviors.

methodsThis cluster-randomized trial was conducted in partnership with nine organizations (e.g., food focused non-profits) across four states in the United States. Partner organizations selected 33 community sites that reached individuals with lower-income and limited access to healthy food. Eligible study participants were age 18+, the primary household shopper, and lived near/frequented the community site; 699 participants were enrolled across all communities. Sites were randomized in pairs to receive the VV intervention (n = 17 sites) or a planning condition (n = 16 sites) for one year. Outcomes were change in food security, F&V consumption measured by food frequency and 24-hour recalls, dermal carotenoid levels and nutrition-related psychosocial measures. Generalized linear mixed models were used to examine the effect of the intervention while adjusting for clustering within sites and baseline values. Additional analyses compared individuals based on their utilization of the VV (users/non-users) and communities that entered the study after peak COVID-19 shutdowns (Post-COVID sites).

resultsIn the intent-to-treat analyses, there were no statistically significant differences in food security or F&V consumption between intervention and control sites. VV users at post-COVID sites had significantly better (p=0.01) average food security scores (n=102, adj. mean=1.4, SE=0.18) after 1 year than non-users (n=201, adj. mean=2.0, SE 0.15).

conclusionsThis research was the first study to evaluate the effectiveness of mobile markets across states, when implemented by different community organizations. Study implementation, recruitment, and data collection were significantly altered by the COVID-19 pandemic. While the magnitude of changes in F&V intake at post-COVID sites was similar to previous research, we did not find statistically significant differences between groups for F&V intake. Analyses also indicated that VV users improved their food security. Future research will examine how fidelity to the VV model by partners affected participant outcomes.

trial registrationThis trial was registered at https://www.clinicaltrials.gov on January 29, 2020 (NCT04246593).