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Effectiveness and Implementation of a Research Tested Mobile Produce Market

Effectiveness and Implementation of a Research Tested Mobile Produce Market Designed to Improve Diet in Underserved Communities

Status
Completed
Phases
NA
Study type
Interventional
Source
ClinicalTrials.gov
Registry ID
NCT04246593
Enrollment
759
Registered
2020-01-29
Start date
2020-01-13
Completion date
2023-10-11
Last updated
2025-06-05

For informational purposes only — not medical advice. Sourced from public registries and may not reflect the latest updates. Terms

Conditions

Fruit and Vegetable Consumption

Brief summary

Investigators will test the effectiveness of the Veggie Van model across multiple organizations and sites using a cluster-randomized design and will document the implementation process to understand what factors are associated with dietary change and sustainability.

Detailed description

After 9 qualified organizations have been identified among applicants, investigators will randomize proposed Mobile Market (MM) sites (33 total across all partner organizations), to an intervention (Mobile Market program implementation) or comparison condition (extended planning). Randomization will be stratified within each organization so that each organization will have 2 intervention and 2 comparison sites. One organization will have 5 sites. The 5th site will allow for more thorough testing of protocol procedures. This ensures that study groups will be balanced at the organizational level. The condition for which each proposed MM location was selected will be communicated at the time of award. Organizations will communicate to intervention sites that they want to open a MM at that location within the next year. Organizations will communicate to comparison sites that they want to work with them on a food systems planning process to determine if a MM program is the right fit for their location. At the end of the year-long planning process with comparison sites, the organization and proposed MM site will decide together how to proceed (start a MM, apply for grant funding for a different project; etc.). Both arms will undergo community engagement efforts that serve to both identify potential research participants and engage them in the planning for a MM. Intervention sites will work with a community advisory committee to develop an engagement plan to raise community awareness of the forthcoming MM. Comparison sites will work with a community advisory committee to engage community members in a food access planning process. Both intervention and comparison sites will distribute interest forms as part of the community engagement process.Research staff will identify from the interest forms those interested in participating in the study. Consent will be obtained via phone. Phone surveys and in-person data collection will then be completed. * Baseline and 12 month Follow-Up Survey will include dietary-related psychosocial measures These surveys will be administered over the phone. * The main individual-level outcome, change in Fruits and Veggies (F&V) intake at 12 months, will be measured through four 24-hour recalls (2 at baseline and 2 at 12 months) which will be administered over the phone by trained interviewers. One recall at each time point will be from a weekday and the other from a weekend day. Recalls will be collected using the Nutrition Data Systems for Research (NDSR) computer-based software application. A participant will receive The Food Amounts Booklet via mail after the baseline survey to have as a visual reference for the 24-hour recalls. * In addition to survey data, body mass index (BMI) and dermal carotenoids will be measured at in-person data collection events at baseline and 12 months. Market (Intervention Sites) will implement a Mobile Market, weekly, for at least 10 months that will follow the Veggie Van model that includes 3 research supported components: * Share model: Similar to community supported agriculture, this model selects fresh, high quality produce available from local farmers, creates shares of 5-8 types of produce, and delivers to community sites once per week. Customers can also choose to purchase individual produce items; however, based on focus group discussions with customers, it is believed that the share model is a key factor in increasing consumption of a larger quantity and variety of Fruits and Veggies. It also contributes to program sustainability by allowing Mobile Markets to better predict their sales and reduce waste. * Incentives: Prices for a Veggie Van model vary slightly by market location. In some communities, only one reduced price (i.e., lower than market value) is offered. In other communities, where customers are of mixed socioeconomic status, partners offer shares on a sliding scale. Customers can use their ebt card, credit/debit, cash or check to purchase produce shares. To support the subsidized cost of produce for low-income residents, the Veggie Van model offers a full-cost box delivery service to workplaces and schools. However, other communities may be able to take advantage of incentive programs (such as Double Up Food Bucks) to offer reduced costs to those eligible. * Educational Component: The Veggie Van model has a curriculum that consists of monthly themes (e.g., Eating in Season, Healthy Snacks, MyPlate, Reducing Sugar) and weekly lessons which build upon those themes. The lessons are designed to be delivered at the Mobile Market while customers are on line waiting to make a purchase. Accompanying newsletters help reinforce lesson plans and also include information about storing and preparing the produce items in the box that week. Newsletters include seasonal recipes and when possible, cooking demonstrations of these recipes or taste tests of featured produce items are offered at the Mobile Market Partner site.

Interventions

OTHERMobile Market program implementation

Mobile Market program implementation includes utilizing a Veggie Van model which sells reduced cost locally-grown produce in communities with barriers to accessing fresh F&Vs because of availability, cost, or lack of produce preparation skills.The Veggie Van visits sites that already serve the target market (e.g., lower-income housing communities, community health centers, community colleges). While Mobile Market programs vary in their model and operation, we believe that the three components of Veggie Van's success are it's share model, price reductions (incentives), and educational component

Sponsors

University of North Carolina, Chapel Hill
CollaboratorOTHER
National Cancer Institute (NCI)
CollaboratorNIH
University at Buffalo
Lead SponsorOTHER

Study design

Allocation
RANDOMIZED
Intervention model
PARALLEL
Primary purpose
OTHER
Masking
NONE

Eligibility

Sex/Gender
ALL
Age
18 Years to No maximum
Healthy volunteers
Yes

Inclusion criteria

* at least 18 years old, speak English or Spanish * the primary grocery shopper for their household * interested in having more healthy food retail options at or around the proposed Mobile Market site * either frequent the proposed Mobile Market site regularly or live near by

Exclusion criteria

* Individuals will be excluded if they do not meet the above inclusion criteria. They will be excluded if they are planning to leave the area or stop using the proposed Mobile Market site (intervention participants) within the next year.

Design outcomes

Primary

MeasureTime frameDescription
Consumption of Fruits and Vegetables12 monthsChange in Fruit & Vegetable (F&V) intake (servings/day) at 12 months will be calculated from four 24-hour recalls (2 at baseline and 2 at 12-months) which will be administered over the phone by trained interviewers (in English or Spanish). One recall at each time point will be from a weekday and the other from a weekend day. The 24-hour dietary recalls will be collected using the Nutrition Data Systems for Research (NDSR) computer-based software application developed at the University of Minnesota Nutrition Coordinating Center (NCC); NDSR uses a five pass interview approach with interview prompts in English and Spanish (49). The NCC Food and Nutrient Database serves as the source of food composition information in NDSR (50). When a participant completes their in-person data collection, participants will receive The Food Amounts Booklet to have as a visual reference during the 24-hour recall. This booklet is compatible with the NDSR program.

Secondary

MeasureTime frameDescription
Body Mass Index12 monthsBMI will be calculated at baseline and 12 months from weight measured using a Seca 876 digital scale (maximum capacity of 250 kg) and height measured to the nearest 1/8 inch using a Seca stadiometer. Weight and height will be combined to report BMI in kg/m\^2
Dermal Carotenoids12 monthsDermal Carotenoids will be measured using a finger scan technology called the Veggie Meter which relies on pressure mediated Raman Spectroscopy (RS) and is thought to be a valid indicator of changes in skin carotenoids in response to dietary carotenoid consumption. Dermal Carotenoids are measured on a scale of 0 to 800, with 0 representing the absence of dermal carotenoids and 800 representing the maximum possible score for dietary carotenoids. A higher dermal carotenoid score indicates a greater presence of dietary carotenoids, and as such a better outcome. Change between baseline and follow-up scores will be calculated for each group.

Other

MeasureTime frameDescription
Psychosocial Measures - Self-efficacy12 monthsSelf-efficacy to purchase, prepare and eat fresh F&V were measured using a 10-point Likert scale, where 10 indicates easiest (most self-efficacy, better outcome) and 1 indicates hardest (least self-efficacy, worse outcome), applied to a selection of 8 items adapted from a study of shoppers where self-efficacy was shown to be correlated with nutrition behaviors and will serve as a comprehensive assessment of the effect of the educational intervention. The 8 items' scores were summed to create a total self-efficacy score ranging from 8 (least total self-efficacy, worse outcome) to 80 (most total self-efficacy, better outcome) for each participant. The measured outcome is the difference between the mean baseline total self-efficacy score and the mean follow-up total self-efficacy score for each group (change).
Psychosocial Measures - Benefits (Expectations)12 monthsBenefits (expectations) and barriers to eating F&V were measured with 12 questions using a 4-point Likert scale (1 indicates strongly disagree, 2 indicates disagree, 3 indicates agree, and 4 indicates strongly agree) previously tested in lower-income adults which reflects common benefits/barriers found in the literature. The 12 individual question scores were summed to generate the total barriers score, with a minimum score of 12 (strongly disagree) and a maximum score of 48 (strongly agree). For all scales, a higher number indicates higher perceived barriers and therefore a worse outcome. The lower the score the better the outcome.

Countries

United States

Participant flow

Recruitment details

Community-based organizations selected as study partners facilitated participant recruitment through a 2-month community engagement period prior to the intervention. If recruitment goals were not met, recruitment continued for up to two months after the intervention period started. Intervention/delayed-intervention control activities occurred at partner sites on a rolling basis; the first participant was enrolled January 13, 2020 and the last was enrolled September 25, 2022.

Pre-assignment details

Of 759 eligible participants enrolled in the study, 699 were included in analysis as 60 participants were removed because the partner organization operating the intervention/delayed-intervention control sites they were assigned to dropped out of the study.

Participants by arm

ArmCount
Intervention - Market
Partner sites that are randomized to the Intervention - Market will plan and start (or expand) a Mobile Market and run the Market weekly for at least 10 months (non necessarily nonconsecutive). The Mobile Market will follow the Veggie Van Model which includes a share model, price reductions (incentives), and an educational component. Mobile Market program implementation: Mobile Market program implementation includes utilizing a Veggie Van model which sells reduced cost locally-grown produce in communities with barriers to accessing fresh F&Vs because of availability, cost, or lack of produce preparation skills.The Veggie Van visits sites that already serve the target market (e.g., lower-income housing communities, community health centers, community colleges). While Mobile Market programs vary in their model and operation, we believe that the three components of Veggie Van's success are it's share model, price reductions (incentives), and educational component
426
Control - Planning
At Control - Planning (comparison) sites, engagement will focus on involving community members in food access program planning and research. It is anticipated that each organization will create one or more community advisory committees to oversee their food access work. At comparison sites, engagement efforts will be more generally centered on food access and understanding what types of programs would be most acceptable. Examples of community engagement activities include community forums and listening sessions, informational tables at community events, and establishment of text, e-mail or social media sites for ongoing communication and feedback around food access issues. As part of this community engagement work, partners will collect contact information from community members that will assist in the data collection process.
273
Total699

Withdrawals & dropouts

PeriodReasonFG000FG001
Overall StudyLost to Follow-up12471
Overall StudyMoved out of area/became ineligible31
Overall StudyReason unknown42
Overall StudyWithdrawal by Subject1413

Baseline characteristics

CharacteristicIntervention - MarketControl - PlanningTotal
Age, Categorical
<=18 years
0 Participants0 Participants0 Participants
Age, Categorical
>=65 years
50 Participants59 Participants109 Participants
Age, Categorical
Between 18 and 65 years
359 Participants197 Participants556 Participants
Body Mass Index (BMI)30.58 kg/m^2
STANDARD_DEVIATION 7.46
31.91 kg/m^2
STANDARD_DEVIATION 8.34
31.1 kg/m^2
STANDARD_DEVIATION 7.83
Ethnicity (NIH/OMB)
Hispanic or Latino
52 Participants21 Participants73 Participants
Ethnicity (NIH/OMB)
Not Hispanic or Latino
374 Participants252 Participants626 Participants
Ethnicity (NIH/OMB)
Unknown or Not Reported
0 Participants0 Participants0 Participants
Race (NIH/OMB)
American Indian or Alaska Native
5 Participants1 Participants6 Participants
Race (NIH/OMB)
Asian
9 Participants5 Participants14 Participants
Race (NIH/OMB)
Black or African American
174 Participants150 Participants324 Participants
Race (NIH/OMB)
More than one race
17 Participants10 Participants27 Participants
Race (NIH/OMB)
Native Hawaiian or Other Pacific Islander
2 Participants0 Participants2 Participants
Race (NIH/OMB)
Unknown or Not Reported
30 Participants15 Participants45 Participants
Race (NIH/OMB)
White
189 Participants92 Participants281 Participants
Region of Enrollment
United States
426 participants273 participants699 participants
Sex/Gender, Customized
Female
359 Participants230 Participants589 Participants
Sex/Gender, Customized
Male
64 Participants43 Participants107 Participants
Sex/Gender, Customized
Other/Refused/Missing
3 Participants0 Participants3 Participants

Adverse events

Event typeEG000
affected / at risk
EG001
affected / at risk
deaths
Total, all-cause mortality
0 / 4260 / 273
other
Total, other adverse events
0 / 4260 / 273
serious
Total, serious adverse events
0 / 4260 / 273

Outcome results

Primary

Consumption of Fruits and Vegetables

Change in Fruit & Vegetable (F&V) intake (servings/day) at 12 months will be calculated from four 24-hour recalls (2 at baseline and 2 at 12-months) which will be administered over the phone by trained interviewers (in English or Spanish). One recall at each time point will be from a weekday and the other from a weekend day. The 24-hour dietary recalls will be collected using the Nutrition Data Systems for Research (NDSR) computer-based software application developed at the University of Minnesota Nutrition Coordinating Center (NCC); NDSR uses a five pass interview approach with interview prompts in English and Spanish (49). The NCC Food and Nutrient Database serves as the source of food composition information in NDSR (50). When a participant completes their in-person data collection, participants will receive The Food Amounts Booklet to have as a visual reference during the 24-hour recall. This booklet is compatible with the NDSR program.

Time frame: 12 months

Population: The food environment and shopping behaviors were significantly impacted by the COVID-19 pandemic in 2020. Many intervention participants did not attend the mobile market. We analyzed the data according to participants' self-reported intervention usage. We combined intervention participants who reported never using the intervention with the Control - Planning (comparison) arm participants, as these participants all did not receive/use the intervention.

ArmMeasureValue (MEAN)Dispersion
Mobile Market Intervention UsersConsumption of Fruits and Vegetables-0.24 servings/dayStandard Error 0.44
Mobile Market Intervention Non-UsersConsumption of Fruits and Vegetables-0.13 servings/dayStandard Error 0.28
p-value: 0.84GLMM
Secondary

Body Mass Index

BMI will be calculated at baseline and 12 months from weight measured using a Seca 876 digital scale (maximum capacity of 250 kg) and height measured to the nearest 1/8 inch using a Seca stadiometer. Weight and height will be combined to report BMI in kg/m\^2

Time frame: 12 months

ArmMeasureValue (MEAN)Dispersion
Mobile Market Intervention UsersBody Mass Index-0.05 Change in mean kg/m^2Standard Error 0.77
Mobile Market Intervention Non-UsersBody Mass Index-0.54 Change in mean kg/m^2Standard Error 0.86
p-value: 0.61GLMM
Secondary

Dermal Carotenoids

Dermal Carotenoids will be measured using a finger scan technology called the Veggie Meter which relies on pressure mediated Raman Spectroscopy (RS) and is thought to be a valid indicator of changes in skin carotenoids in response to dietary carotenoid consumption. Dermal Carotenoids are measured on a scale of 0 to 800, with 0 representing the absence of dermal carotenoids and 800 representing the maximum possible score for dietary carotenoids. A higher dermal carotenoid score indicates a greater presence of dietary carotenoids, and as such a better outcome. Change between baseline and follow-up scores will be calculated for each group.

Time frame: 12 months

ArmMeasureValue (MEAN)Dispersion
Mobile Market Intervention UsersDermal Carotenoids-22.19 score on a scaleStandard Error 29.89
Mobile Market Intervention Non-UsersDermal Carotenoids5.83 score on a scaleStandard Error 31.35
p-value: 0.53GLMM
Other Pre-specified

Psychosocial Measures - Benefits (Expectations)

Benefits (expectations) and barriers to eating F&V were measured with 12 questions using a 4-point Likert scale (1 indicates strongly disagree, 2 indicates disagree, 3 indicates agree, and 4 indicates strongly agree) previously tested in lower-income adults which reflects common benefits/barriers found in the literature. The 12 individual question scores were summed to generate the total barriers score, with a minimum score of 12 (strongly disagree) and a maximum score of 48 (strongly agree). For all scales, a higher number indicates higher perceived barriers and therefore a worse outcome. The lower the score the better the outcome.

Time frame: 12 months

ArmMeasureValue (MEAN)Dispersion
Mobile Market Intervention UsersPsychosocial Measures - Benefits (Expectations)-0.32 score on a scaleStandard Error 0.73
Mobile Market Intervention Non-UsersPsychosocial Measures - Benefits (Expectations)0.23 score on a scaleStandard Error 0.86
p-value: 0.63GLMM
Other Pre-specified

Psychosocial Measures - Self-efficacy

Self-efficacy to purchase, prepare and eat fresh F&V were measured using a 10-point Likert scale, where 10 indicates easiest (most self-efficacy, better outcome) and 1 indicates hardest (least self-efficacy, worse outcome), applied to a selection of 8 items adapted from a study of shoppers where self-efficacy was shown to be correlated with nutrition behaviors and will serve as a comprehensive assessment of the effect of the educational intervention. The 8 items' scores were summed to create a total self-efficacy score ranging from 8 (least total self-efficacy, worse outcome) to 80 (most total self-efficacy, better outcome) for each participant. The measured outcome is the difference between the mean baseline total self-efficacy score and the mean follow-up total self-efficacy score for each group (change).

Time frame: 12 months

ArmMeasureValue (MEAN)Dispersion
Mobile Market Intervention UsersPsychosocial Measures - Self-efficacy0.84 score on a scaleStandard Error 1.04
Mobile Market Intervention Non-UsersPsychosocial Measures - Self-efficacy1.37 score on a scaleStandard Error 1.28
p-value: 0.75GLMM

Source: ClinicalTrials.gov · Data processed: Jun 15, 2026