Innovative Nutrition Practices in Pediatric Health Care: Assessment of a Fruit and Vegetable Prescription Program for Children in Need
Phase: NA
Conditions: Exposure to Fruit and Vegetable Prescription Program
Sponsor: Michigan State University

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Assessment of a Fruit and Vegetable Prescription Program for Children 
 
Trial #: NCT04767282 
 
Study Protocol and Analysis Plan 
Submitted: 11/06/2020 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 

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Background 
The 2020-2025 Dietary Guidelines for Americans state that children and adolescents should 
consume fruits and vegetables regularly to support healthy development and prevent chronic 
disease. The US Department of Agriculture recommends a minimum daily intake of 1.5 cups of 
fruit and 1.5 cups of vegetables for females ages 9-13 years and 1.5 cups of fruit and 2 cups of 
vegetables for males ages 9-13 years.1,2 These recommendations often are unfulfilled, especially 
within low-income households.3-8 While most young people across the US struggle to attain even 
the minimum daily recommendations related to fruit and vegetable consumption,7,8 ultra-
processed foods now comprise the majority of total energy intake among US youths 2-19 years.9 
Increased adiposity related to shifts in diet and exercise have prompted public health action to 
encourage intake of fresh or minimally processed food among children and adolescents.10  
 
Eating patterns during childhood and adolescence are important to long-term diet and health11-13 
and play a key role in the development of diet-related chronic health conditions.13-19 To support 
healthy food choices while also addressing food access challenges, some health care clinics have 
introduced fruit and vegetable prescription programs.20-23 The programs differ in design and 
scope, yet most include health provider-issued prescriptions that patients can exchange, without 
charge, for fresh produce at local farmers’ markets, mobile markets, or food stores. While 
programs are increasingly available across the country, most target adults with chronic health 
conditions, offering fruit and vegetable prescriptions as a disease-management strategy.22-25 Few 
studies have examined whether, and to what degree, exposure to pediatric fruit and vegetable 
prescription programs influences the diet and health of youth.26,27 With childhood and 
adolescence representing a critical period of development when many are establishing lifelong 
dietary behaviors,11-13 these programs are likely to have meaningful health implications. 
 
In February 2016, a large university-affiliated pediatric clinic in a low-income urban community 
introduced Michigan’s first pediatric fruit and vegetable prescription program. The program 
included physician-issued $15 prescriptions for fresh produce that were distributed after the 
office visit. Prescriptions were redeemable only for fresh fruits and vegetables at the downtown 
farmers’ market or a local mobile market that traveled throughout the city. Caregivers whose 
children were exposed to this year-round fruit and vegetable prescription program viewed it as 
effective in improving child dietary patterns and household food security.28 Moreover, 
preliminary research, following an expansion of the identical prescription program to a second 
pediatric clinic, disclosed improvements in food security measures and dietary behaviors of 
children following one year of exposure to this program.26 
 
In 2018, the US Farm Bill included produce prescription programs, through the Gus Schumacher 
Nutrition Incentive Program, for the first time.29 The legislation provided federal grant support 
for new and existing fruit and vegetable prescription programs. Still, these programs continue to 
focus largely on adults with diet-related chronic health conditions. Few programs are designed 
specifically to promote healthy eating and prevent disease among vulnerable youth. The current 
study, conducted across three large pediatric clinics in Flint, Michigan, is designed to provide 
empirical evidence to evaluate the effectiveness of pediatric fruit and vegetable prescriptions 
provided to youth and gain insights regarding the duration and intensity of exposure needed to 
influence changes in food security, dietary patterns, and weight status among children and their 
caregivers.  

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Study aims and hypotheses 
This study will assess whether exposure to a pediatric fruit and vegetable prescription program 
(FVPP) that provides one $15 prescription for fresh produce to every child at each office visit 
might account for later changes in dietary intake, food security, and weight status. 
Demographically similar pediatric patient groups with varying levels of exposure to the FVPP at 
baseline will be compared: high exposure (>24 months), moderate exposure (12-24 months), and 
no previous exposure. Children with no previous exposure will be introduced to the FVPP, and 
researchers will track changes in dietary intake, food security, and weight status over two years. 
The specific aims of the study are to (1) compare baseline dietary intake, food security, and 
weight status between pediatric patients with varying levels of exposure to the FVPP; (2) 
measure changes in diet, food security, and weight status before and after never-before-exposed 
children are introduced to the FVPP; and (3) compare mean 12- and 24-month follow-up 
measures of dietary intake, food security, and weight status in the initial no exposure group to 
baseline measures in the high exposure group. A central expectation is that greater exposure to 
this FVPP will promote intake of fruits and vegetables, better food security, and lower rates of 
childhood obesity. 
 
The current study, in design and approach, is grounded in the theoretical framework of 
Bandura’s Social Cognitive Theory (SCT). SCT explains behavior using a three-stage, dynamic 
model linking personal factors, environmental factors, and behavior.30,31 This study’s SCT 
framework involves collaborations with partnering physicians and local agricultural leaders to 
support environmental change and social learning. Since children’s dietary intake is generally 
guided by their parents, critically important environmental factors, such as access to fruits and 
vegetables as well as caregiver modeling of the healthy behaviors, are of particular 
importance.32,33 Consistent with SCT, we also posit that self-efficacy is central to behavior 
change. Accordingly, self-efficacy for consuming fruits and vegetables, which refers to one’s 
judgment over one’s capability to enact the behavior, is important to change dietary behavior.34 
By grounding the study with the theoretical framework of SCT, we suggest that pediatrician 
issuance of a prescription for fruits and vegetables to every child at each office visit will promote 
food access and self-efficacy to consume healthy foods. Furthermore, pediatrician messaging to 
children and caregivers will influence health-promoting behaviors linked to increased 
consumption of fruits and vegetables. 
 
 
Study Design 
This study will include a cross-sectional analysis of data from a consecutive sample of caregiver-
child dyads with varying levels of exposure to a fruit and vegetable prescription program (FVPP) 
that provides one $15 prescription for fresh produce to every child during pediatric office visits. 
Considering the importance of dietary patterns during childhood on long-term diet and health11-13 
alongside evidence that indicates adolescence is the specific period when food insecurity has the 
greatest potential to negatively impact the diet,35 data collection and analyses will focus 
specifically on children and adolescents ages 8-16 years. A total of 700 caregiver-child dyads 
(one caregiver and one child per household) will be enrolled in the study, with approximately 
200 dyads enrolled at clinic 1 (high exposure); 200 dyads enrolled at clinic 2 (moderate 
exposure), and 300 dyads enrolled at clinic 3 (no previous exposure to the FVPP). A description 
of the clinics is provided with our explanation of the ‘Setting’ for this study. 

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Dyad enrollment will be based on exposure to the FVPP as defined by caregiver-reported and 
clinic-verified length of time that the participating child has been a patient at one of three 
partnering clinics. Accordingly, we expect dyads to cluster based on pediatric clinics as follows: 
clinic 1 (high exposure), clinic 2 (moderate exposure), and clinic 3 (no previous exposure). A 
sample of approximately 200 pediatric patients newly exposed to the FVPP at clinic 3 will be 
followed for a period of two years as part of a non-controlled longitudinal intervention trial that 
will examine changes in dietary patterns, food security, and weight status over time.  
 
 
Setting 
Flint, Michigan, is a low-income urban city where an approximate 60% of children live in 
poverty, and full-service grocery stores located inside the city are limited.36 The city lacks 
resources and nutritional options, like many low-income urban cities in the US. As a result, many 
children consume insufficient nutrient-dense foods and excessive poor-quality, calorie-dense 
foods.20 Local stores in Flint tend to offer lower-quality foods and fewer healthy foods than 
offered in higher-income neighborhoods.28,37-39 Along with long-lasting issues related to food 
access and affordability coupled with recovery from a drinking water crisis,40 the SARS-CoV-2 
coronavirus pandemic has disproportionately affected Flint and surrounding Genesee County. 
Confirmed COVID-19 case prevalence has consistently placed the county in the top ranks (#5) 
among 83 Michigan counties. In ordinary times, with constrained wealth, and many families in 
poverty, under- or unemployed, Flint faces extraordinary health challenges. The pandemic has 
compounded these ordinary challenges, with results that include more hungry children and 
increased food insecurity.  
 
The current study will occur at three clinics in Flint serving demographically similar patient 
populations. 
• Clinic 1 is a university-affiliated pediatric clinic that introduced Michigan’s first pediatric 
fruit and vegetable prescription program. The program began as a pilot in February 2016. 
After several program iterations and refinements, all patients currently receive one $15 
prescription for fresh fruits and vegetables at every office visit. Pediatricians at clinic 1 
have distributed approximately 40,000 prescriptions since the FVPP was introduced.  
 
• Clinic 2 is one of the largest private-practice pediatric clinics in Flint, serving over 3,000 
young patients. The FVPP was introduced at clinic 2 in August 2018 as part of a grant to 
assess the feasibility and preliminary effectiveness of the FVPP at a second clinic site.26 
Clinic 2 was selected for this expansion because of the clinic size, demographics of the 
patient population which closely match clinic 1, and use of an electronic medical record 
(EMR) system that is identical to clinic 1 (allowing easy tracking of monthly prescription 
distribution rates). Clinic 2 has distributed over 15,000 prescriptions since August 2018.  
 
• Clinic 3 is the largest pediatric clinic in Genesee County, with Flint as its urban center. 
Expansion of the FVPP to clinic 3 will substantially increase program reach among 
vulnerable children and families living in Flint. Last year, clinic 3 had over 12,000 
pediatric visits. It has a comparable patient population to clinics 1 and 2, serving only 
children in need who are residents of Genesee County.  
 

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Participants and recruitment 
A sample of 250 caregiver-child dyads presenting at clinic 1, 250 caregiver-child dyads at clinic 
2, and 350 caregiver-child dyads at clinic 3 will be assessed for eligibility, with 700 total dyads 
enrolled (anticipated 10-15% not meeting eligibility and 10% refusal based on a previous study). 
To control for confounders, we will adopt a balancing strategy that consists of recruiting in the 
study children who have approximately the same age, sex, and race across the three clinical 
settings. These children will not be balanced according to variables pertaining directly to the 
exposures (e.g., duration of FVPP exposure).  
 
With target samples of 200, 200, and 300 caregiver-child dyads enrolled in clinic 1 - high 
exposure, clinic 2 - moderate exposure, and clinic 3 - no previous exposure, respectively, we 
have well above 90% power to jointly detect modest relative differences in the baseline mean 
intake of vegetables of 20% from clinic 2 to clinic 3 and 38% from clinic 1 to clinic 3. This 
calculation assumes an underdispersed Poisson model with a dispersion parameter of 0.82, 
derived using previously published data on the mean intake of vegetables of 0.72 cup and a 
standard deviation of 0.77 cup in the settings with no prior FVPP exposure.20 Likewise, with 300 
caregiver-child dyads enrolled in clinic 3, we have well above 90% power to detect a modest 
temporal improvement in the mean intake of vegetables of 25% over 12 months (0.72 cup at 
baseline versus 0.90 cup at 12-month follow-up). This calculation assumes a correlated Poisson 
model for underdispersed count data with timepoint dispersion parameter of 0.82, and a modest 
temporal correlation of 0.2. Increasing values of the temporal correlation greatly improves the 
statistical power. Finally, estimation of FVPP effects will specify two-tailed tests with alpha set 
at the 0.05 level. 
 
Inclusion criteria for all participants include a restriction to children aged between 8 and 16 years 
at enrollment; the caregiver and child must speak English. An estimated 2% of the Flint 
population cannot speak English. A legal guardian must be present at enrollment and must sign 
an informed consent document; each child must assent to participation. Inclusion criteria for 
clinic 1 (high exposure) will include participation in the FVPP for over 24 months. Inclusion 
criteria for clinic 2 participants (moderate exposure) will include participation in the FVPP for 12 
to 24 months. Inclusion criteria for clinic 3 participants (no exposure) will include no previous 
exposure to the FVPP. Potential participants at clinic 3 will be excluded if the household 
includes a sibling who already enrolled in the research study or if there has been movement of 
the patient from one clinic to another clinic (<3% of patients). 
 
 
Fruit and Vegetable Prescription Program (FVPP) 
Fruit and vegetable prescriptions, analogous to medical prescriptions, are electronically 
prescribed by pediatricians and given to patients. They are intended to promote a healthy food 
environment within the home.41 For our study, eligible vendors comprise the downtown Flint 
Farmers’ Market (FFM) and Flint Fresh, a mobile market and food hub that offers locally grown, 
home-delivered, fresh produce boxes. Vendors accept the prescriptions ($15 each) as if they 
were gift certificates or vouchers for any fresh fruits or vegetables. In partnership with FFM and 
Flint Fresh, prescription redemption rates are recorded and tracked. Over time, the redemption of 
prescriptions has been increasing (from under 30% when the program was initiated to its current 
redemption rate of approximately 50%).  

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Clinics 1 and 2 have developed an efficient and reliable method to record and track prescription 
distribution rates. Fruit and vegetable prescriptions are built using the Epic electronic medical 
record (EMR) system, to order and print each prescription, and to track individual and aggregate 
monthly distribution rates. Key personnel on the current study will train pediatricians and staff at 
clinic 3 regarding EMR procedures to order, print, and track prescriptions through their EMR 
system, eClinicalWorks (eCW). The study protocol will capture monthly reports that cover 
topics such as the number of patients seen in the clinic and prescriptions distributed.  
 
To monitor prescription redemption, FFM vendors will collect paper prescriptions redeemed for 
fresh produce and turn them into the FFM management office at the end of each month for 
payment. Prescriptions will be collected, sorted, stored, and entered into a database for tracking 
purposes. A similar method will be used to track and record monthly prescription redemption 
through Flint Fresh, including tracking of virtual prescriptions which were introduced during the 
COVID-19 pandemic as pediatric telehealth visits increased. 
 
 
Data collection procedures 
Consent/assent procedures and data collection at baseline will be carried out in a private clinic 
location, such as a patient examination room. A trained research assistant (RA) will follow our 
study’s Institutional Review Board (IRB)-approved protocol for consent, child assent, and data 
collection (e.g., of dietary data). The RA will provide detailed instructions regarding the study, 
survey completion, and how to make use of an iPad and its interface with a secure digital 
platform (Research Electronic Data Capture or REDCap). Researchers will copy the signed 
consent and assent forms at pediatric offices and provide to families upon enrollment in the study 
or researchers will email copies of signed e-consent and assent and provide to families upon 
enrollment in the study. Caregivers and children will be told that their participation is voluntary; 
that they may stop participating at any time; that they may choose how much information they 
feel comfortable sharing; that their individual identity will not be shared with anyone; and that in 
the writing of any results, pseudonyms will be used. Families will be told by researchers as well 
as pediatricians and office staff that their acceptance or refusal to participate in the research 
study will not impact their eligibility to receive the fruit and vegetable prescription. Each 
member of the caregiver-child dyad will separately complete a standardized questionnaire with 
pre-worded demographic and pilot-tested survey questions that assess dietary patterns, food 
security, and food access.20 The RA will assist children with survey completion. Child body 
mass index (BMI) percentile and BMI z-score will be calculated based on measured height and 
weight, as described in the ‘Primary Outcome Measures’ section. Key constructs and study 
measures are listed in Table 1. 
 
 
 
 
 
 
 
 
 

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Table 1. Key Constructs  
Domains 
Constructs 
Measures 
Instruments 
Personal 
Outcomes 
Child self-
efficacy 
• Self-efficacy for fruit consumption 
• Self-efficacy for vegetable consumption 
• Proxy efficacy to influence parents to 
make fruits and vegetables available 
• Self-efficacy 
questionnaire42,43 
Caregiver self-
efficacy 
• Self-efficacy to purchase and consume 
fruits and vegetables 
• Selected questions from 
Food Attitudes and 
Behaviors Survey44 
Environmental 
Outcomes 
Exposure to 
fruit and 
vegetable 
prescriptions 
• Number of months child has been a 
patient at fruit and vegetable 
prescription participating pediatric 
office 
• Number of fruit and vegetable 
prescriptions received 
• Medical chart review  
Caregiver 
dietary patterns 
Mean daily servings of: 
• Total fruits 
• Total vegetables 
• Total fruits and vegetables 
• National Cancer Institute 
Fruit & Vegetable Intake 
“All Day” Screener45,46 
Caregiver fruit 
and vegetable 
access 
• Access to fruits and vegetables 
• Barriers to access 
• Social support to access 
• Food Attitudes and 
Behaviors Survey44 
• Michigan Behavioral Risk 
Factor Surveillance Survey 
Food security 
• Perceived food security among youth 
• Food Security Survey 
Module for Youth47 
• Household food security and hunger 
• US Household Food 
Security Module: Six Item 
Short Form48  
Behavioral 
Outcomes 
Child fruit and 
vegetable 
consumption 
Mean daily servings of: 
• Total fruits 
• Total whole fruits 
• Total vegetables 
• Total fruits and vegetables 
• Two non-consecutive 
dietary recalls49 
• Block Kids Food 
Screener50 
Child dietary 
patterns 
• Nutrient estimates 
• Number of servings by food groups 
• Healthy eating index 
• Block Kids Food 
Screener50 
Secondary 
Outcomes 
Child weight 
status 
• Body mass index (BMI) 
• BMI percentile, BMI z-score 
• Measured weight 
• Measured height 

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To compare baseline dietary intake, food security, and weight status between pediatric patients 
with varying levels of exposure to the FVPP, we will collect study measures at baseline from 700 
dyads at each of three partnering clinics. To measure changes in diet, food security, and weight 
status when never-exposed children are introduced to the FVPP, we will follow approximately 
200 dyads from clinic 3, collecting study measures at baseline, 12- and 24-month follow-up. In 
addition to posters, brochures, and websites that explain the FVPP, caregivers at clinic 3 will be 
reminded of each follow-up visit through reminder cards and telephone calls. 
 
REDCap provides data security measures designed to prevent unauthorized access, disclosure, 
alteration, and use of data. Data from the completed evaluation tools will be stored in REDCap 
project database. Children and caregivers will be assigned identification numbers upon 
enrollment in the study. All data will be de-identified within the data management system, and 
de-identified data will be exported for analyses.  
 
Any modifications to the approved protocol will be submitted to Michigan State University IRB 
for review and approval prior to implementation. Furthermore, although the likelihood of any 
adverse event in this trial is remote, we have formalized our Data and Safety Monitoring Plan to 
include a designated Data and Safety Monitor. This Monitor will have the authority to 
recommend termination of the trial if he makes the determination that unacceptable adverse 
events have taken place. Should any adverse events occur, these will be immediately reported to 
Michigan State University IRB for review. 
 
 
Benefits 
Completion of our study aims will provide empirical evidence for the effectiveness of Produce 
Prescription Programs, which were recently added to the US Farm Bill through the Gus 
Schumacher Nutrition Incentive Program. Our study will share insights regarding the duration 
and intensity of exposure necessary to influence changes in food security, dietary patterns, and 
weight status when fruit and vegetable prescriptions are provided to pediatric patients. 
Furthermore, our results will be especially important to pediatricians and primary care physicians 
who recognize the consequences of food insecurity among young patients and are seeking 
tangible solutions that not only provide food to hungry children but ensure that the food provided 
is high in nutrients needed to support healthy growth and development.  
 
 
Reasonably Foreseeable Risks 
There are no known risks to participants. 
 
 
Primary outcome measures  
Child dietary patterns 
Because the children’s dietary patterns across gradients of exposure to the FVPP are of primary 
interest, we will administer two non-consecutive 24-hour dietary recalls and one validated food 
frequency screener. The dietary recall data will cover the 24 hours before enrollment and a 
second 24-hour interval that occurs just before a post-baseline assessment completed by the RA 
within seven days after baseline. The Automated Self-Administered 24-Hour (ASA-24) Dietary 

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Assessment Tool will be used for these assessments. The 24-hour dietary recall is a valid 
measure for assessing the dietary intake of children ages eight years and older.49 The RA also 
will administer Block Kids Food Screener, a food frequency questionnaire, to allow for the 
assessment of usual and long-term eating behaviors with relatively little administration burden. 
Block Kids Food Screener has shown good relative validity for children and adolescents.50 Its 41 
items assess the frequency and quantity in which foods and beverages were consumed over the 
previous week. 
 
After data collection, a dietary analysis, using the Block Online Analysis System, will provide 
nutrient estimates and the number of servings by food group. We will use these data to evaluate 
the mean daily intake of total fruits and vegetables, total vegetables, total fruits, and whole fruits. 
The Healthy Eating Index (HEI) will be generated from the dietary data for use as a measure of 
the diet quality of the children.51,52 
 
Child-reported food security 
Children ages 12 years and older will complete the Self-Administered Food Security Survey 
Module for Youth (SAFSSMY). Although the SAFSSMY was found to have adequate internal 
validity for children ages 12 years and older, it is not recommended for use with younger 
children.47 The sum of affirmative responses (“a lot” or “sometimes”) to module questions will 
provide the child’s initial raw score on the perceived food security scale, with food security 
status assigned based on raw score (0-1=high/marginal food security; 2-5=low food security; 6-
9=very low food security). This study’s sample size is sufficient for a confirmatory factor 
analysis based on Item Response Theory, which will be used to evaluate whether the unit weight 
assigned to each item can be improved upon. 
 
Household food security  
Caregivers will complete the US Household Food Security Module: Six Item Short Form 
(National Center for Health Statistics) to assess household food insecurity and hunger.48 The sum 
of affirmative responses (“often”, “sometimes”, “yes”, “almost every month”, “some months but 
not every month”) on the module will serve as the household’s raw score. Food security status 
will be assigned based on the raw score (0-1=high/marginal food security; 2-4=low food 
security; 5-6=very low food security). We will use this data to calculate household food security 
and hunger. Here also, after planned analyses based on the raw score, a confirmatory factor 
analysis approach will be taken in a post-estimation exploratory analysis. 
 
Child weight, height, and BMI status  
The trained RA will take two successive measurements of each child’s weight and height within 
the patient examination room, without shoes or heavy outer garments. Then, the RA will enter 
the data electronically using the REDCap secure digital platform. Weight will be measured to the 
closest 0.2 kg on a digital platform scale accurate to 200 kg. Height will be measured to the 
closest 0.1 cm using a portable stadiometer. Body mass index (BMI), which correlates with more 
expensive and direct measures of body fat in children (e.g., dual-energy x-ray absorptiometry) 
will be calculated from child weight and height (weight (kg)/[height (m)]2).53 The derived BMI 
can be categorized into normed percentiles by sex and age to serve as an indicator of overweight 
and obesity.54  
 

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Secondary outcome measures 
Self-efficacy 
Per our theoretical model, improving self-efficacy for consuming fruits and vegetables is 
important to change dietary behavior.34 A validated questionnaire will be administered at each 
time point to assess caregiver self-efficacy to purchase and consume fruits and vegetables as well 
as child self-efficacy to consume fruits and vegetables and proxy efficacy to influence parents to 
make fruits and vegetables available.42,43 
 
Caregiver dietary patterns  
To investigate whether exposure to the FVPP is associated with increased fruit and vegetable 
consumption among caregivers, dietary data from caregivers will be collected using the National 
Cancer Institute Fruit & Vegetable Intake “All Day” Screener which asks frequency and portion 
size questions about nine food items. This self-administered screener will provide an estimate of 
the median intake of fruit and vegetable servings in adults.45,46 This will be used to calculate the 
mean daily intake of vegetables and total fruits.  
 
Caregiver food access  
To evaluate access to fruits and vegetables as well as related barriers and social supports, we will 
ask caregivers to complete selected questions from the Food Attitudes and Behaviors Survey.44 
Responses will be answered on a 5-point Likert scale, ranging from 1, being “strongly disagree”, 
to 5, being “strongly agree”. Finally, caregivers will complete four questions related to fruit and 
vegetable quality and access in neighborhood stores from the Michigan Behavioral Risk Factor 
Surveillance Survey. 
 
 
Covariates 
To the extent possible, this study’s potential covariates have been chosen from the NIH 
Environmental Influences on Child Health Outcomes (ECHO)-wide protocol because these 
variables are well-established and broadly applicable in dietary research, and each can be 
assessed using low-burden measurements.55 Within ECHO, there are many measured variables 
from the Patient-Reported Outcomes Measurement Information System (PROMIS). PROMIS 
was developed and validated to assess patient-reported outcomes for clinical research and 
practice.56 
 
Child physical activity  
To assess physical activity, children and adolescents will complete the eight-question PROMIS 
Physical Activity questionnaire. This instrument will measure a child’s performance of activities 
that require physical actions.  
 
Child sleep patterns  
Measures chosen by the NIH ECHO working group teams will assess sleep-related constructs: 
PROMIS Sleep Disturbance and PROMIS Sleep-Related Impairment. Children will complete 
these surveys, which were designed for self-administration at ages 8-17 years. Assessing these 
domains (n=15 total questions) will allow for a more nuanced understanding of how sleep might 
confound or interact with other variables. 
 

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Caregiver weight and height 
The RA will ask for a self-report of caregiver weight and height. These variables might moderate 
the estimated associations between FVPP exposure levels and child outcomes. 
 
Baseline sociodemographic covariates and other characteristics of interest 
This set of baseline covariates, all assessed by the RA, includes household income, caregiver and 
child education, ethnicity, and age, as well as the name of the neighborhood or community of 
residence. As noted above, caregiver weight and height (by self-report) also will be included as a 
covariate and potential moderator. The iPad assessment also will ask the caregiver about 
participation in food assistance programs (other than FVPP) and food shopping behaviors. 
 
 
Statistical analysis plan 
Consistent with general best practices regarding analytic procedures,57 we will employ multiple 
statistical techniques to test the robustness and sensitivity of our findings across various methods. 
Specifically, parametric analyses efficient under correct model specification will first be 
conducted, followed by robust semiparametric and nonparametric analyses. All efforts will also 
be made during the design and the data collection stages to minimize attrition and the rate of 
missing data. At the analysis stage, however, multiple imputation techniques coupled with 
Markov Chain Monte Carlo simulations will be used for handling missing at random 
mechanisms. Informative missing data mechanisms will be accommodated via pattern-mixture 
modeling and selection modeling, followed by a sensitivity analysis.58-61  
 
Because the study calls for a non-randomized design, the analysis will rely on statistical 
techniques to control for confounders as a source of potential biases. Specifically, a classical 
approach based on regression adjustment, in which potential confounders are added to the linear 
predictor, will be adopted. The adjusted analysis will control for well-known confounders between 
exposure to FVPP and both the primary and secondary outcomes, regardless of their statistical 
significance. Further comparative analyses will be conducted to determine additional sources of 
confounders. Specifically, bivariate analyses will be conducted to evaluate the associations between 
the study group, the study endpoints and the child’s level variables (e.g., age, gender, and race) and 
the caregiver’s level variables (e.g., household-reported income, education, and other nutrition 
program involvement).  
 
An alternative balancing strategy based on propensity scores will be used to mitigate potential 
differences at baseline among participants in the three study groups. These scores will be used to 
derive an unbiased estimate of the average treatment effect of FVPP on study endpoints. The 
generalized propensity score to account for multiple levels of treatment in the spirit of Imbens 
will be estimated with a multinomial logistic regression.62 To estimate the FVPP effects, we will 
use an elaborated multinomial logistic model that includes the child’s level, the caregiver’s level 
covariates, and functions thereof (e.g., interactions).  
 
The choice of analytic methods will be guided by the specific aims, the nature of study endpoints 
and that of relevant data. Independence models will be used to compare baseline dietary intake, 
food security, and weight status between pediatric patients with varying levels of exposure to the 
FVPP. Correlated data models will be used to evaluate (1) changes in diet, food security, and 

12 
 
weight status when never-exposed children are introduced to the FVPP; and (2) compare mean 
follow-up measures of dietary intake, food security, and weight status in the initial no exposure 
group to baseline measures in the high exposure group. 
 
Comparison of baseline measures based on FVPP exposure  
Multiple linear regression will be used to assess the relationship between mean daily intake of 
fruits and vegetables and level of exposure to the FVPP. A basic logistic regression model will 
be used to evaluate the adjusted effect of the child-level exposure to the FVPP on the obesity 
probability. An ordinal logistic regression model will be used to evaluate the adjusted effects of 
the child-level exposure to the FVPP on food security (measured as an ordinal outcome). Within 
this class of models, we will entertain the popular proportional odds model with prior evaluation 
of the assumption of the proportionality of odds across the ordered levels of food security. These 
analyses will be adjusted for variables such as food assistance program participation, nutrition 
education program participation, child race, child age, child gender, caregiver-reported income 
group, caregiver-reported weight status, caregiver education, and child-reported mean daily 
intake of fruits and vegetables.  
 
 
Evaluation of changes when children are introduced to the FVPP 
After baseline data collection, periodic follow-up assessments will be conducted to study 
changes in diet, food security, and weight status among children newly exposed to the FVPP at 
clinic 3. Because of the repeated nature of the data generated for this aim, we will consider 
methods that accommodate the within-child and/or the within-caregiver association. For 
continuous outcomes (e.g., dietary intake), repeated measures models such as linear mixed 
models and repeated ANOVA models, will be entertained in view of their robustness to certain 
types of missing data. These classes of models will be used to assess changes from baseline at 
key points in the study.63,64 For ordinal endpoints such as food security (with ordered levels), a 
generalized linear mixed effects model with cumulative logits will be entertained. To examine 
whether there is a significant improvement in child-reported food security from baseline, contrast 
representing the difference in log-odds between baseline and follow-up will be evaluated. 
Alternatively, GEE counterparts of these likelihood-based models (that use the sandwich-based 
correction in lieu of the model-based variance-covariance matrix of the parameter estimates) will 
also be considered.65 
 
 
Comparison of mean follow-up measures in the initial no exposure group to baseline 
measures in the high exposure group 
At follow-up, measures of dietary intake, food security, and weight status in a group of children 
newly exposed to the FVPP will be compared to baseline measures of children with high 
exposure to the FVPP (>24 months). For example, to compare measures of dietary intake (at 12 
months and 24 months) in the newly exposed group to those of the highly exposed group, the 
class of linear mixed models and repeated ANOVA models will be considered. These models 
will be similar to those of aim 2, with the additional flexibility of group-specific time-point 
effects. For ordinal outcomes (e.g., food security) and binary outcomes (e.g., obesity), a 
generalized linear mixed effects model will be used. Alternative models such as GEE models 
will also be entertained.  

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Discussion 
Although the US Farm Bill provides funding opportunities for produce prescription programs, 
there are multiple knowledge gaps related to duration and intensity of exposure; ideal program 
timing and length; implementation components; and overall effectiveness. Current FVPPs vary 
widely in content, scope, duration, and intensity across the US, although most programs target 
adults with diet-related chronic health conditions and offer fruit and vegetable prescriptions as a 
disease-management strategy.22,23 The current study is unique in design as it emphasizes the 
critical role fruits and vegetables play in disease prevention using a pediatric FVPP that has 
previously demonstrated feasibility.26 Furthermore, rich and productive partnerships with a 
network of pediatricians and agricultural leaders across Flint and Michigan have been created. 
These partnerships, alongside consistent feedback from caregivers and families,28 have aided in 
the development of this reproducible program that considers fundamental challenges with FVPP 
implementation within busy clinical settings.  
 
Completion of study aims will provide evidence for the effectiveness of FVPP and gain insights 
regarding the duration and intensity of exposure necessary to influence changes in food security, 
dietary patterns, and weight status when fruit and vegetable prescriptions are provided to 
pediatric patients. Results will be shared broadly at local, state, and national conferences as well 
as through peer-reviewed publications. Findings will be particularly important to pediatricians 
and primary care physicians seeking tangible solutions to address both food insecurity and poor 
dietary habits among young patients. Furthermore, the results of this study are likely to inform 
policy decisions related to state and federally supported nutrition prescription programs. 
 
 
List of abbreviations 
FVPP: fruit and vegetable prescription program 
SCT: Social Cognitive Theory 
EMR: electronic medical record 
FFM: Flint Farmers’ Market 
eCW: eClinicalWorks 
RA: research assistant 
REDCap: Research Electronic Data Capture 
BMI: body mass index 
ASA-24: Automated Self-Administered 24-Hour 
HEI: Healthy Eating Index 
SAFSSMY: Self-Administered Food Security Survey Module for Youth 
ECHO: Environmental Influences on Child Health Outcomes 
PROMIS: Patient-Reported Outcomes Measurements Information System 
RCT: randomized controlled trial 
 
 
Ethics approval and consent to participate  
The current study will be performed in accordance with the Declaration of Helsinki, and 
Michigan State University Institutional Review Board approved the study (STUDY00003370). 
Written consent by one caregiver and written assent by each participating child are required for 
study participation. 

14 
 
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