Impact of BC Farmers' Market Nutrition Coupon Program on Diet Quality and Psychosocial Well-being of Low-income Adults

Not Applicable

Completed

• Conditions: Diet, Healthy; Health Risk Behaviors
• Interventions: Other: Food coupons; Other: Nutrition skill-building

• Registration Number: NCT03952338
• Lead Sponsor: University of Calgary

Brief Summary

The British Columbia (BC) Farmers' Market Nutrition Coupon Program (FMNCP) provides low-income households with $21/week in coupons to purchase healthy foods at farmers' markets and supportive nutrition skill-building activities. This randomized controlled trial will assess the impact of the BC FMNCP on the overall diet quality (primary outcome), diet quality subscores, mental well-being, sense of community, experiences of food insecurity, risk of malnutrition (secondary outcomes) and subjective social status (exploratory outcome) of low-income adults immediately post-intervention and 16 weeks post-intervention.

Detailed Description

Background: The British Columbia (BC) Farmers' Market Nutrition Coupon Program (FMNCP) is a healthy eating initiative funded by the BC Ministry of Health. The program provides low-income households with $21/week in coupons to purchase healthy foods at farmers' markets and supportive nutrition skill-building activities. It is not clear if the BC FMNCP is achieving its aims of improving the diet quality, well-being and health of low-income adults, as its outcomes have not been investigated, and studies of similar programs are limited by weak designs that cannot demonstrate causality. This randomized controlled trial will assess the impact of the FMNCP on the overall diet quality (primary outcome), diet quality subscores, mental well-being, sense of community, experiences of food insecurity, risk of malnutrition (secondary outcomes) and subjective social status (exploratory outcome) of low-income adults immediately post-intervention and 16 weeks post-intervention. A qualitative investigation will also explore mechanisms of action and strategies to maximize positive program impacts.

Methods: Low-income adults (≥ 18 years) from up to 15 rural and urban communities will be randomized to a FMNCP intervention (n=132) or a no-intervention control group (n=132), with a 1:1 allocation ratio. An independent researcher from the Clinical Research Unit at the University of Calgary will generate a blocked randomization sequence that stratifies participants into blocks according to sex (male, female), geographic location (rural, urban), pregnancy (yes, no) and breastfeeding (yes, no). In the existing BC FMNCP, community partners distribute one to two sheets of coupons per week (each sheet contains $21 in coupons) to program participants for a total of 16 sheets. Coupons can be used over 16-20 weeks to purchase fruits, vegetables, dairy, meat/poultry/fish, eggs, nuts, and cut herbs at participating BC farmers' markets. However, to allow sufficient time to recruit participants for this study, community partners will distribute 16 coupon sheets to the FMNCP group over 10-15 weeks (households with 5-8 individuals will receive 32 coupon sheets). To ensure participants receive all 16 coupon sheets, community partners will provide two coupon sheets per household during the first 1-6 weeks of the intervention. Participants in the FMNCP group will also be invited to participate in nutrition skill-building activities (e.g., cooking classes). At baseline (0 weeks), immediately post-intervention (10-15 weeks) and 16 weeks post-intervention (26-31 weeks), participants will access a pilot-tested web-based platform to report sociodemographics, health-related variables, mental well-being, sense of community, experiences of food insecurity, risk of malnutrition and subjective social status. Dietary intake will be assessed via two 24-hour dietary recalls at each time point using the Automated Self-Administered Dietary Assessment Tool for Canada (ASA24-Canada-2018). Diet quality scores will be calculated using the Healthy Eating Index-2015. In addition, immediately post-intervention only, participants will report whether they received FMNCP coupons and attended nutrition skill-building activities (to assess contamination of the control group), how often and how much of their own money was spent at farmers' markets during the intervention period and the types of foods purchased.

Data analysis: Descriptive analyses will be conducted to examine participant characteristics by group at each time point. Characteristics of study completers (i.e., provided data 16-weeks post-intervention) and non-completers will also be compared.

Analyses will be intention-to-treat, in which participants will be analysed within the groups to which they were randomized regardless of adherence (e.g., failure to redeem coupons) or dropout. The analyses will include all participants who provided data at baseline. Repeated measures mixed-effect regression will assess differences in mean HEI-2015 scores, HEI-2015 subscores, mental well-being, sense of community, and subjective social status between the FMNCP and control groups immediately post-intervention and 16-weeks post-intervention. Repeated measures multinomial logistic regression will be used to assess differences in the odds of experiencing household food insecurity and risk of malnutrition for the FMNCP group compared to the control group immediately post-intervention and 16-weeks post-intervention. Statistical models will include intervention group (FMNCP vs control), time from baseline, intervention-by-time interaction, blocking variables (i.e., sex, rural/urban, pregnancy, breastfeeding), baseline values of the outcome, and household size as fixed effects covariates. Participant-specific (i.e., repeated measures) variations in outcomes will be modeled using random effects. Models will also include covariates specific to each outcome to increase the precision of estimates (86). For the primary outcome of overall diet quality, models will include the following: children living in the home (yes, no), sex, age, BMI, marital status, race/ethnicity, perceived health, smoking, day of data collection, and educational level. Adjusted group differences (i.e., FMNCP group vs control group) in outcomes will be estimated using 95% confidence intervals and corresponding p-values.

Subgroup analyses will examine whether the impact of the intervention on primary and secondary outcomes differs according to age group or sex. Dose-response analyses will examine whether the impact of the BC FMNCP on overall diet quality depends on the number of coupons redeemed and the number of nutrition skill-building activities attended. Interactions will be retained in statistical models if p\<0.10. Analyses will be conducted in Stata (v15.1, Stata Corp, TX, USA), with p\<0.05 indicating statistically significant differences between groups. Data interpretation will jointly consider effect sizes, confidence intervals and statistical significance.

Expected outcomes: Findings will show whether and how a scalable population-level policy that links the agricultural and health sectors influences diet quality, psychosocial well-being and other outcomes among low-income adults. Study findings will inform program adjustments to improve participant outcomes. Other jurisdictions can use these data to determine whether and how to initiate similar programs.

Post-hoc analysis: In a post-hoc analysis, a random forest model will be used to explore heterogeneity of program effects on diet quality (total HEI-2015 scores) among different subgroups of FMNCP study participants. Candidate predictors entered into the algorithm will include all variables examined at baseline, including sociodemographic characteristics (e.g., age, sex, and income) and health-related variables (e.g., self-rated health and smoking). The outcome of the random forest analysis will be total HEI-2015 scores for both the FMNCP and control groups.

Basic Information
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Recruitment & Eligibility
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Study & Design
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Trial Locations

Study Timeline

• Study First Submitted: 2019-05-10
• Study First Submitted QC: 2019-05-15
• Study First Posted: 2019-05-16
• Study Start: 2019-06-03
• Primary Completion: 2020-03-31
• Study Completion: 2020-03-31
• Status Verified: 2020-06
• Results First Submitted: 2024-01-22
• Results First Submitted QC: 2024-10-30
• Last Update Submitted: 2024-10-30
• Results First Posted: 2024-12-16
• Last Update Posted: 2024-12-16

Recruitment & Eligibility

• Status: COMPLETED
• Sex: All
• Target Recruitment: 285

Inclusion Criteria

Not provided

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Exclusion Criteria

• Does not meet one or more inclusion criteria

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Study & Design

• Study Type: INTERVENTIONAL
• Study Design: PARALLEL

Arm && Interventions

Group	Intervention	Description
Nutrition Coupons	Nutrition skill-building	Participants in the FMNCP group will receive 16 coupon sheets (each sheet contains $21 in coupons) over 10-15 weeks (households with 5-8 individuals will receive 32 coupon sheets) to purchase fruits, vegetables, dairy, meat/poultry/fish, eggs, nuts, and cut herbs at participating BC farmers' markets. To ensure participants receive all 16 coupon sheets, community partners will provide two coupon sheets per household during the first 1-6 weeks of the intervention. Participants in the FMNCP group will also be invited to participate in nutrition skill-building activities (e.g., cooking classes) offered by community partners throughout the intervention period, however participation is not required (this is consistent with the existing FMNCP).
Nutrition Coupons	Food coupons	Participants in the FMNCP group will receive 16 coupon sheets (each sheet contains $21 in coupons) over 10-15 weeks (households with 5-8 individuals will receive 32 coupon sheets) to purchase fruits, vegetables, dairy, meat/poultry/fish, eggs, nuts, and cut herbs at participating BC farmers' markets. To ensure participants receive all 16 coupon sheets, community partners will provide two coupon sheets per household during the first 1-6 weeks of the intervention. Participants in the FMNCP group will also be invited to participate in nutrition skill-building activities (e.g., cooking classes) offered by community partners throughout the intervention period, however participation is not required (this is consistent with the existing FMNCP).

Primary Outcome Measures

Name	Time	Method
Difference Between Intervention and Control Groups in Mean Overall Diet Quality by Healthy Eating Index-2015 Scores Immediately Post-intervention (10-15 Weeks)	post-intervention (10-15 weeks).	Difference between intervention and control groups in mean overall diet quality by Healthy Eating Index-2015 scores immediately post-intervention (10-15 weeks). Healthy Eating Index-2015 scores are calculated from 24-hour dietary recalls and can range from 0-100, with a higher score indicating higher diet quality.
Difference Between Intervention and Control Groups in Mean Overall Diet Quality by Healthy Eating Index-2015 Scores at 16 Weeks Post-intervention (26-31 Weeks)	16 weeks post-intervention (26-31 weeks).	Difference between intervention and control groups in mean overall diet quality by Healthy Eating Index-2015 scores at 16 weeks post-intervention (26-31 weeks). Healthy Eating Index-2015 scores are calculated from 24-hour dietary recalls and can range from 0-100, with a higher score indicating higher diet quality.

Secondary Outcome Measures

Name	Time	Method
Difference Between Intervention and Control Groups in Mean Mental Well-being Scores by Warwick-Edinburgh Mental Well-Being Scale Immediately Post-intervention (10-15 Weeks)	post-intervention (10-15 weeks).	Items on the 14-item Warwick-Edinburgh Mental Well-Being Scale are self-reported over the past two weeks. There are 14 items with 5 response categories (1=none of the time; 5=all of the time), summed to provide a single score ranging from 14-70. A higher score indicates higher perceived mental well-being.
Difference Between Intervention and Control Groups in Mean Mental Well-being Scores by Warwick-Edinburgh Mental Well-Being Scale at 16 Weeks Post-intervention (26-31 Weeks)	16 weeks post-intervention (26-31 weeks).	Items on the 14-item Warwick-Edinburgh Mental Well-Being Scale are self-reported over the past two weeks. There are 14 items with 5 response categories (1=none of the time; 5=all of the time), summed to provide a single score ranging from 14-70. A higher score indicates higher perceived mental well-being.
Difference Between Intervention and Control Groups in Mean Sense of Community by the Brief Sense of Community Scale Immediately Post-intervention (10-15 Weeks)	post-intervention (10-15 weeks).	Items on the 8-item Brief Sense of Community Scale are self-reported in which each item is scored using a Likert Scale of 1 (strongly disagree) to 5 (strongly agree). Scores can range from 8-40. A higher score indicates a stronger sense of community.
Difference Between Intervention and Control Groups in Mean Sense of Community by the Brief Sense of Community Scale at 16 Weeks Post-intervention (26-31 Weeks)	16 weeks post-intervention (26-31 weeks).	Items on the 8-item Brief Sense of Community Scale are self-reported in which each item is scored using a Likert Scale of 1 (strongly disagree) to 5 (strongly agree). Scores can range from 8-40. A higher score indicates a stronger sense of community.
Difference Between Intervention and Control Groups in the Odds of Experiencing Household Food Insecurity Immediately Post-intervention (10-15 Weeks)	post-intervention (10-15 weeks).	Difference between intervention and control groups in the odds of experiencing household food insecurity immediately post-intervention (10-15 weeks). Items on the 18-item Household Food Security Survey Module are self-reported in relation to experiences in the past month.
Difference Between Intervention and Control Groups in the Odds of Experiencing Household Food Insecurity at 16 Weeks Post-intervention (26-31 Weeks)	16 weeks post-intervention (26-31 weeks).	Difference between intervention and control groups in the odds of experiencing household food insecurity at 16 weeks post-intervention (26-31 weeks). Items on the 18-item Household Food Security Survey Module are self-reported in relation to experiences in the past month.
Difference Between Intervention and Control Groups in the Odds of Malnutrition by Malnutrition Universal Screening Tool Immediately Post-intervention (10-15 Weeks)	post-intervention (10-15 weeks).	Items on the Malnutrition Universal Screening Tool are self-reported and based on BMI (scored as 0= \>20, 1= 18.5-20, 2 = \<18.5) and percent of unplanned weight loss in the past 3-4 months (scored as 0 = \<5%, 1 = 5-10%, 2 = \>10%). Overall risk of malnutrition will be scored as 0=low risk, 1= medium risk, and \>= 2= high risk.
Difference Between Intervention and Control Groups in the Odds of Malnutrition by Malnutrition Universal Screening Tool at 16 Weeks Post-intervention (26-31 Weeks)	16 weeks post-intervention (26-31 weeks).	Items on the Malnutrition Universal Screening Tool are self-reported and based on BMI (scored as 0= \>20, 1= 18.5-20, 2 = \<18.5) and percent of unplanned weight loss in the past 3-4 months (scored as 0 = \<5%, 1 = 5-10%, 2 = \>10%). Overall risk of malnutrition will be scored as 0=low risk, 1= medium risk, and \>= 2= high risk.
Difference Between Intervention and Control Groups in Mean Diet Quality Subscores by Healthy Eating Index-2015 Immediately Post-intervention (10-15 Weeks)	post-intervention (10-15 weeks).	Healthy Eating Index (HEI)-2015 scores are calculated from 24-hour dietary recalls. HEI-2015 total scores can range from 0-100, with a higher score indicating a higher diet quality. HEI-2015 total scores are calculated by summing subscores for adequacy components (total fruits, whole fruits, total vegetables, greens and beans, whole grains, dairy, total protein foods, seafood and plant proteins, fatty acids) and moderation components (refined grains, sodium, added sugars, saturated fats). Possible subscale scores are as follows: Adequacy components (higher score indicates a higher intake): Total vegetables (0-5) Greens and beans (0-5) Total fruits (0-5) Whole fruits (0-5) Whole grains (0-10) Dairy (0-10) Total protein foods (0-5) Seafood and plant proteins (0-5) Fatty acids (0-10); Moderation components (higher score indicates a lower intake) Sodium (0-10) Refined grains (0-10) Saturated fats (0-10) Added sugars (0-10)
Difference Between Intervention and Control Groups in Mean Diet Quality Subscores by Healthy Eating Index-2015 at 16 Weeks Post-intervention (26-31 Weeks)	16 weeks post-intervention (26-31 weeks).	Healthy Eating Index (HEI)-2015 scores are calculated from 24-hour dietary recalls. HEI-2015 total scores can range from 0-100, with a higher score indicating a higher diet quality. HEI-2015 total scores are calculated by summing subscores for adequacy components (total fruits, whole fruits, total vegetables, greens and beans, whole grains, dairy, total protein foods, seafood and plant proteins, fatty acids) and moderation components (refined grains, sodium, added sugars, saturated fats). Possible subscale scores are as follows: Adequacy components (higher score indicates a higher intake): Total vegetables (0-5) Greens and beans (0-5) Total fruits (0-5) Whole fruits (0-5) Whole grains (0-10) Dairy (0-10) Total protein foods (0-5) Seafood and plant proteins (0-5) Fatty acids (0-10); Moderation components (higher score indicates a lower intake) Sodium (0-10) Refined grains (0-10) Saturated fats (0-10) Added sugars (0-10)
Difference Between Intervention and Control Groups in the Risk of Experiencing Marginal, Moderate, or Severe Household Food Insecurity Immediately Post-intervention (10-15 Weeks)	post-intervention (10-15 weeks).	Difference between intervention and control groups in the risk of experiencing marginal, moderate, or severe household food insecurity (relative to being food secure) immediately post-intervention (10-15 weeks). Items on the 18-item Household Food Security Survey Module are self-reported in relation to experiences in the past month.
Difference Between Intervention and Control Groups in the Risk of Experiencing Marginal, Moderate, or Severe Household Food Insecurity at 16 Weeks Post-intervention (26-31 Weeks)	16 weeks post-intervention (26-31 weeks).	Difference between intervention and control groups in the risk of experiencing marginal, moderate, or severe household food insecurity (relative to being food secure) at 16 weeks post-intervention (26-31 weeks). Items on the 18-item Household Food Security Survey Module are self-reported in relation to experiences in the past month.
Difference Between Intervention and Control Groups in the Risk of Being at a Medium or High Risk of Malnutrition by Malnutrition Universal Screening Tool Immediately Post-intervention (10-15 Weeks)	post-intervention (10-15 weeks).	Difference between intervention and control groups in the risk of being at a medium or high risk of malnutrition (relative to being at low risk of malnutrition) by Malnutrition Universal Screening Tool immediately post-intervention (10-15 weeks). Items on the Malnutrition Universal Screening Tool are self-reported and based on BMI (scored as 0= \>20, 1= 18.5-20, 2 = \<18.5) and percent of unplanned weight loss in the past 3-4 months (scored as 0 = \<5%, 1 = 5-10%, 2 = \>10%). Overall risk of malnutrition was scored as 0=low risk, 1= medium risk, and \>= 2= high risk.
Difference Between Intervention and Control Groups in the Risk of Being at a Medium or High Risk of Malnutrition by Malnutrition Universal Screening Tool at 16 Weeks Post-intervention (26-31 Weeks)	16 weeks post-intervention (26-31 weeks).	Difference between intervention and control groups in the risk of being at a medium or high risk of malnutrition (relative to being at low risk of malnutrition) by Malnutrition Universal Screening Tool at 16 weeks post-intervention (26-31 weeks). Items on the Malnutrition Universal Screening Tool are self-reported and based on BMI (scored as 0= \>20, 1= 18.5-20, 2 = \<18.5) and percent of unplanned weight loss in the past 3-4 months (scored as 0 = \<5%, 1 = 5-10%, 2 = \>10%). Overall risk of malnutrition was scored as 0=low risk, 1= medium risk, and \>= 2= high risk.

Trial Locations

Locations (1)

Community Partners; 🇨🇦 Rural And Urban, British Columbia, Canada