Optimizing an mHealth Intervention to Change Food Purchasing Behaviors for Cancer Prevention
Phase: NA
Conditions: Cancer
Sponsor: Drexel University

Title: Optimizing an mHealth Intervention to Change Food Purchasing Behaviors for Cancer 
Prevention 
NCT04947150 
Document date: 3/25/21 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 

Protocol 
Study Design 
This study is a National Cancer Institute (NCI)-funded pilot, randomized controlled trial 
(R21CA252933) utilizing a factorial design to test the effect of four different intervention 
components on dietary intake and grocery store purchases. The four factors yield 16 different 
combinations of intervention components (Table 1). An equal number of participants were 
randomized to receive vs. not receive each of the four experimental intervention components. 
For example, half of participants have their food purchasing data monitored by a coach and half 
do not have this feature as part of their intervention. As another example, half of participants 
were randomly assigned to have household member involvement included in their intervention 
package, but this randomization was done independently of that for coach monitoring (i.e., the 
four experimental intervention components were not “bundled” together). Baseline covariates 
used for randomization included biological sex, body mass index (BMI), age, household size, 
and dietary adherence score.  
Ethics Approval 
This study was approved by the Drexel University Institutional Review Board (Study ID 
#2003007695) on March 13, 2021. 
Participants, Eligibility, and Recruitment 
The study enrolled 62 index participants, as well as 31 household members who are serving 
in a support role. Participants were recruited from the Philadelphia area in two cohorts via 
targeted mailings, social media outreach, and Craigslist listings, and was supported in part by 
community recruitment resources from Thomas Jefferson University’s Sidney Kimmel 
Cancer Center. Specifically, Jefferson’s Regional Liaison Office employed their “honest 
broker” system which aided in identifying and contacting potential participants using internal 
communication resources, community contacts, and other available resources (e.g., 
participants within the Jefferson community who matched eligibility criteria were emailed 
about their interest in participating). Interested individuals completed a screening survey and, 
if deemed preliminarily eligible, attended an information session via videoconferencing. 
After the session, those interested in participating attended a baseline assessment, in which 
their final eligibility was determined.   
Index participants were required to be age 18 or older and fluent in English. In addition, 
participants were required to be the primary grocery shopper in their household and report 
shopping at stores that could passively stream item-level data from a store loyalty card to the 
project portal (Walmart, Target, ShopRite, or Wegmans). Inclusion criteria also included 
having a smartphone with an iOS or Android operating system that was compatible with the 
program app and living in a household with another adult who indicated willingness to 
participate in a support role. Exclusion criteria were as follows: medical condition or 
psychiatric condition (e.g., active substance abuse, eating disorder) that would be a poor 
match with program content or limit ability to comply with program dietary 
recommendations; plans to enroll in another lifestyle modification program within 6 months 
of program start; bariatric surgery history; pregnant or breastfeeding or plans to become 
pregnant in the next 6 months. All index participants provided written informed consent for 
participation, as did the 31 household members of index participants randomized to HH.  

Intervention  
Uniform components  
All index participants attend a nutrition education workshop (three sessions, 90 minutes each, 
all delivered via videoconferencing software) focused on eating a diet consistent with 
WCRF/AICR guidelines. Content is organized around the key WCRF/AICR dietary 
recommendations: 1) eat a diet rich in whole grains, vegetables, and fruit; 2) limit 
consumption of highly processed foods; 3) limit consumption of red and processed meat; 4) 
eliminate consumption of sugar-sweetened beverages. Sessions consist of psychoeducation 
about these nutrition recommendations, group discussions on health behavior change (e.g., 
common triggers for eating behavior), didactics on behavioral skills (e.g., stimulus control, 
functional analysis, problem solving), and hands-on practice (e.g., reading a nutrition label). 
Each workshop concludes with goal setting and meal planning, where participants identify 
concrete guideline-related goals for the coming week, create a weekly meal plan, and begin 
constructing a grocery list for relevant items. They are encouraged to finish their meal plan 
and grocery list independently after each session. Workshop sessions consist of 10-15 
participants each. Coaches are experienced in delivering lifestyle modification and have an 
MS or Ph.D. in psychology, nutrition, or a related field. Each participant has continuity 
working with the same coach for all workshop sessions and, if applicable, any additional 
condition-specific contacts (i.e., extra workshop sessions, coaching calls, and coach 
messages). 
 
All index participants also download an app that was created for this program (Figure 2). A 
key feature of the app is a display of graphs that reflect how well the participant’s grocery 
shopping purchases align with each of the program recommendations across the previous 4 
weeks. Participants are encouraged to utilize these graphs to track their progress and 
improvement towards recommendations over time. The grocery shopping data displayed in 
the graphs is passively collected from participant's store loyalty accounts, as described 
below. During the 20-week intervention period, all participants also receive once-weekly 
educational messages in the app that remind them of program dietary recommendations and 
behavioral strategies that can promote adherence (e.g., planning, self-monitoring, goal 
setting). Message content includes tips for meeting program guidelines such as swapping out 
processed snacks for healthier alternatives, or recipe ideas to incorporate fruits and 
vegetables (e.g., “Replacing high-calorie, processed foods with fruits, vegetables, whole 
grains, beans, and legumes can help you feel fuller longer, have more energy, and better 
manage cravings and appetite, all of which can help you manage your weight. Identify one 
thing you could do this week to continue to make progress on the goal of replacing processed 
foods with healthier items”). These messages are standardized, such that the content in any 
given week’s message is the same for all participants.  
Experimental intervention components and contact time 
As described next, the four experimental intervention components are each provided to 50% 
of participants, in addition to the three workshop sessions and standard weekly messages that 
all participants receive. The study was designed such that program contact time varies by 
condition, in order to evaluate the benefit of added contact time. The total number of 
workshop sessions ranges from 3 to 5, with 26% of participants assigned to 3 sessions (i.e., 
no extra workshop sessions), 48% assigned to 4 sessions (i.e., one extra workshop session), 

and 26% assigned to 5 sessions (i.e., two extra workshop sessions). The total number of 
coach calls ranges from 0 to 9, with 18% of participants assigned to 0 calls, 29% assigned to 
3 calls, 39% assigned to 6 calls, and 14% assigned to 9 calls.  
As described in detail next, all participants receive one message from the app each week that 
includes standardized educational content, and half of participants have benefits of change 
content appended to the message. For half of participants, delivery of the educational app 
message is location-triggered. Half of participants (i.e., those who receive coach monitoring) 
also receive a second message in the app each week, which is written by their coach. Half of 
participants have a message sent to their household member each week. 
Location-triggered messages 
Participants randomized to receive this component receive their weekly educational message 
in the program app when their smartphone is within a 50-meter geofence around designated 
grocery stores. At baseline, participants provided information about venues where they 
regularly grocery shop, for geofence programming. If the system does not detect the 
designated location in a given week (e.g., the participant does not go to the grocery store), the 
app message is delivered at the end of the week. The message is only delivered once per 
week, even if the participant is at a grocery shopping location more than once.  
Participants who are not assigned to location-triggered message delivery receive their weekly 
educational messages at a fixed time (i.e., Sundays at 10am), regardless of location. The 
content of the messages does not differ according to whether location-triggered messaging is 
provided or not.      
Reflections on benefits of change 
Participants randomized to receive the benefits of change component receive one extra 60-
minute workshop session, to reflect on the anticipated benefits of purchasing healthy foods. 
They also attend three brief, individual coaching calls (20 minutes each) to further discuss 
personally meaningful benefits of change (at weeks 9, 13, and 17). Personalized content on 
their anticipated benefits is also added to each educational app message delivered after week 
5. During the benefits of change workshop session, participants individually complete an 
exercise identifying short- and long-term benefits of healthy eating that are important to 
them, and message content is programmed according to the responses they record. (Example: 
“Making healthy choices today will pay off in the long run because [I will be modeling these 
choices for my children, and they will benefit from healthier eating as well],” where 
bracketed input was generated by the participant.)  
Participants who do not receive the benefits of change component do not attend the 
additional workshop or these three coach calls focused on benefits of change, and do not 
receive additional message content.  
Coach monitoring 
For participants assigned to receive coach monitoring, the coach accesses a web-based portal 
where they view the participant’s food purchasing data, which is passively collected from the 
point of purchase using store loyalty accounts. The coach sends the participant a personalized 
message each week in the app, sharing feedback and observations from the food purchasing 
data. The participant also completes three calls with the coach (20 minutes each, held in 

weeks 4, 10, and 15) designed to further enhance supportive accountability for program 
goals. The coach messages and calls provide reinforcement for purchases consistent with 
program goals (particularly those that represent a change from baseline) and express concern 
for areas in which adherence is low.  
If a participant is not assigned to receive coach monitoring, the coach has no objective 
information about food purchasing and the participant does not receive any personalized 
coach messages in the app or phone calls focused on coach monitoring.    
Household support 
Participants assigned to receive household support as part of the intervention select one adult 
in their household to serve in the support role. This household member receives weekly text 
messages (Example: “Your household member is likely trying to keep up new healthy habits 
for meal planning and grocery shopping. Identify one thing you can do to support their 
efforts with these changes this week. For instance, communicating in advance about meal 
and snack preferences, showing appreciation, or offering to look for healthy recipes to try.”). 
Additionally, the index participant and household member jointly participate in one extra 60-
minute workshop session and three 20-minute coaching calls focused on household support 
(held in weeks 7, 11, and 16). (The household member does not attend any other workshop 
sessions or coaching calls). The content of the workshops and calls is designed to elicit 
support for changing the home food environment and enhance supportive accountability by 
making household members aware of the index participant’s commitment to improving 
dietary intake.  
For index participants who are not assigned to receive this intervention component, 
household members have no program involvement.   
Measures 
Feasibility and acceptability 
Feasibility and acceptability data are being collected and will be compared to pre-established 
benchmarks. Recruitment feasibility will be operationalized with a benchmark of >5 
participants enrolled per month of recruitment and <30% of those otherwise 
interested/eligible refusing participation. Retention feasibility will be operationalized with a 
benchmark of >70% of participants completing each follow-up assessment. Feasibility and 
acceptability of food purchasing data will be operationalized with a benchmark of >90% of 
participants having food purchase digital data successfully captured. Feasibility for message 
delivery will be assessed by location-triggered messaging delivery, with successful receipt of 
messages measured by <5% of delivery encountering technological problems. User-rated 
acceptability will be measured by the benchmark of a mean rating >28 on the Treatment 
Acceptability Questionnaire (adapted, 8-items; 7-point Likert scale; given at 10 and 20 
weeks). Qualitative information about acceptability will be collected via post-intervention 
focus groups. Focus groups will be audio recorded, transcribed, with responses coded for 
themes and patterns, and used to further refine the intervention for future testing.  
Dietary intake 
All participants complete dietary intake questionnaires at 0 and 20 weeks. Cohort 1 participants 
completed three days of food recalls at each time point, administered by the Automated Self-

Administered 24-hour Dietary Recall (ASA24), an NCI-designed software tool [86]. ASA24 is 
based on the well-validated automated multiple pass method, which has been shown to be as or 
more accurate than nutritionist-administered 24-hour food recall when using doubly labeled 
water as the criterion.  
 
After baseline administration of the ASA24, many Cohort 1 participants reported that they 
perceived this measure to be excessively burdensome. Due to the low acceptability, we replaced 
the ASA24 with the Diet History Questionnaire (DHQ-III) for Cohort 2 participants, due to its 
streamlined format and reduced completion time. The DHQ-III is a food frequency questionnaire 
developed by the NCI. The nutrient and food group database for DHQ-III is based on a 
compilation of national 24-hour dietary recall data from the National Health and Nutrition 
Examination Surveys. Cohort 2 participants completed the DHQ-III at baseline and will 
complete it again at 20 weeks.  Given the different measures of dietary intake, differences in 
dietary intake variables across waves will be assessed and analyses on dietary intake will be 
conducted separately for each wave. 
 
Both the ASA24 and DHQ-III provide item-level nutritional information for all food/drinks 
consumed as well as daily totals of various nutrient variables. For the NCI recommendation 
specific to highly processed food, food items will be flagged and included in this category based 
on those defined as highly processed based on the widely used NOVA classification system. 
Items in the processed food category include salty snacks, frozen and prepared meals, baked 
goods, dessert, fried potatoes, candy, packaged bread and buns, refined grains, breakfast cereal, 
processed cheese, etc. Relevant items that fall into this category are pulled from the ASA24 
items-level output based on their Food and Nutrient Database for Dietary Studies (FNDDS) food 
code and from the DHQ-III items-level output based on their coding in the NCI’s associated 
nutrient database and included in nutrient total calculations for processed foods. Similarly, sugar-
sweetened drinks are identified in the ASA24 (based on their FNDDS food code) and DHQ-III 
(based on nutrient database) and used to calculate adherence to the relevant guideline. Sugar-
sweetened drinks include non-diet sodas, non-diet fruit drinks, energy drinks, and sugary coffee 
drinks. 
 
Average daily intake of the following items relevant to NCI dietary recommendations will be 
calculated from the ASA24 and DHQ-III:  
1. Fiber: grams of fiber  
2. Fruit and vegetables: cups of all fruit (intact whole or cut fruit not including fruit juices) 
and vegetables (all vegetables excluding starches) 
3. Added sugar from processed food: grams of added sugar consumed from items flagged as 
highly processed (as described above) 
4. Saturated fat from processed food: grams of saturated fat consumed from items flagged 
as highly processed (as described above) 
5. Sodium from processed food: milligrams of sodium consumed from items flagged as 
highly processed (as described above) 
6. Red meat: ounces of beef, veal, pork, lamb, and game meat  
7. Processed meat: grams of frankfurters, sausages, corned beef, and luncheon meat made 
from beef, pork or poultry 
8. Sugar-sweetened drinks: ounces of sugar-sweetened beverages (as defined above) 

 
Given that NCI dietary recommendations for red and processed meat are on the week (vs. daily) 
level, average daily intake of red and processed meat are prorated to reflect intake over 7 total 
days. 
 
Scores for adherence in each domain of the NCI dietary recommendations are calculated based 
on the 0, 0.5, 1 cutoff values established previously, where 1 reflects fully meeting the 
recommended level of intake, 0.5 indicates partially meeting recommended levels, and 0 reflects 
failure to meet the recommendation. When guidelines include multiple sub-categories (e.g., fiber 
and fruits/vegetables), the guideline score was calculated as the average of adherence on sub-
categories. Two overall adherence scores were calculated: 1) the sum of adherence on the four 
guidelines (range 0-4) and 2) average adherence on the four guidelines (range 0-1). The 
subscores are: a) average of adherence scores for fiber and fruits/vegetables, b) average of 
adherence scores for added sugar, saturated fat, and sodium in processed foods, c) average of 
adherence scores for red and processed meats, and d) adherence score for sugar-sweetened 
drinks. 
 
As a secondary outcome for dietary intake, an adapted, 13-item Food Frequency Questionnaire is 
administered at baseline and 20 weeks. Each item pertains to one of the four dietary guidelines 
(e.g., “Whole grain products or high fiber starches”, “Red meats such as beef, pork, lamb”, 
“Non-diet sweet drinks”), and participants are instructed to report the frequency with which they 
ate the foods in the past month with a 6-point Likert-type scale (ranging from 0 - “never” to 5 - 
“twice or more per day”). Total guideline scores will be calculated as the average of responses to 
all items pertaining to that guideline (e.g., guideline 1 as the average of 0-5 response for fiber 
and 0-5 response for fruits/vegetables). 
Mediators  
Consistent with the study’s conceptual model, three potential mediators are measured. An 
adapted Goal Salience Questionnaire is administered at each time point (baseline, 10, and 20 
weeks) to measure dietary goal salience, i.e., the extent to which participants think about 
dietary recommendations when grocery shopping. Motivation for dietary adherence is 
measured with items adapted from the Treatment Self-Regulation Questionnaire [98] at each 
time point. Two measures of household social factors are administered at baseline, 10 weeks, 
and 20 weeks, where items were adapted to apply to one’s household rather than social 
network more broadly: Supportive Accountability Questionnaire and Sallis Social Support 
for Diet.   
Moderators  
Several potential moderators were measured at baseline. Participants completed a self-report 
demographics questionnaire that gathered information about sex, race, ethnicity, age, 
education level, household size, and grocery shopping frequency. To measure the quality of 
the relationship between the index participant and their household member, an adapted 
version of the Relationship Assessment Scale [103] was administered. Weight, height, and 
weight history were measured using an investigator-developed weight history questionnaire.  
Uncontrolled eating, cognitive restraint, and emotional eating were measured with a 21-item 

version of the Three Factor Eating Questionnaire-R21 (TFEQ-21-item version) at baseline. 
The TFEQ will be completed at 10 and 20 weeks as well. 
Household Member Information 
Participating household members are administered the following questionnaires, which will 
be examined in exploratory analyses: an investigator-developed household demographics and 
goals questionnaire (at baseline only), the adapted Food Frequency Questionnaire (same 
instrument administered to index participants, at baseline and 20 weeks), and the Treatment 
Acceptability Questionnaire (same instrument administered to index participants, at 20 
weeks). 
Grocery store purchases 
Beginning four weeks before intervention start date and continuing until four weeks after 
intervention end date, study software, utilizing an application programming interface (API), will 
continuously collect each participant’s item-level food purchases to objectively measure how 
grocery shopping changes over time. Participants provided store account credentials for loyalty 
programs at one or more of the four designated stores (Wegmans, ShopRite, Target, and/or 
Walmart) to the study team at baseline. The API links item-level food purchases with nutrition 
databases (e.g., FNDDS) to create summary nutrition variables, including added sugar, sodium, 
and saturated fat from processed foods for each item in a grocery trip. Change in purchase 
amounts in each nutrition category of interest related to NCI guidelines (e.g., ounces of sugar 
sweetened beverages purchased per week) will be calculated. This will be an exploratory 
outcome because this method of data capture and categorization of grocery purchases is novel, 
and feasibility has not yet been tested.