Optimizing an mHealth Intervention to Change Food Purchasing Behaviors for Cancer Prevention

Goal salience while grocery shopping was measured using an investigator-developed self-report questionnaire. Participants rated 3 questions pertaining to salience of health goals during grocery shopping on a sliding scale from 0 (not at all) to 100 (very much): Scores on these three items were averaged to compute a global Goal Salience total score (range = 0-100), with higher scores indicating higher goal salience.

This pilot study used a factorial design, with 16 conditions and typically 4 participants per condition. The study was designed with the intent to collapse across conditions for all analyses, such that the 8 conditions in which a given factor is ON would be compared to the 8 conditions in which that factor was OFF. Participants are counted multiple times in the table, such that the total number of participants in any ON/OFF condition pair will equal the full sample.

Supportive accountability was measured using 5 items adapted from the Perceptions of Accountability Scale (Chhabria et al., 2020). Participants rated 5 items (e.g., "I feel accountable to others for meeting my dietary goals") on a sliding scale from 0 (not at all) to 100 (very much). Scores on the 5 items were averaged to produce a global Supportive Accountability total score (range 0-100), with higher scores indicating higher perceived supportive accountability to others for dietary/healthy eating goals.

This pilot study used a factorial design, with 16 conditions and typically 4 participants per condition. The study was designed with the intent to collapse across conditions for all analyses, such that the 8 conditions in which a given factor is ON would be compared to the 8 conditions in which that factor was OFF. Participants are counted multiple times in the table, such that the total number of participants in any ON/OFF condition pair will equal the full sample.

Motivation for healthy eating was measured using 10 items adapted from the Treatment Self-Regulation Questionnaire (Levesque et al., 2007). Using the question stem "The reason I would follow a healthy diet is...", participants rated items on a scale from 1 (not at all true) to 7 (very true). Six items were averaged to create a subscale of autonomous Motivation for healthy eating (range 1-7), with higher scores on each subscale indicated higher Autonomous Motivation.

This pilot study used a factorial design, with 16 conditions and typically 4 participants per condition. The study was designed with the intent to collapse across conditions for all analyses, such that the 8 conditions in which a given factor is ON would be compared to the 8 conditions in which that factor was OFF. Participants are counted multiple times in the table, such that the total number of participants in any ON/OFF condition pair will equal the full sample.

Motivation for healthy eating was measured using 10 items adapted from the Treatment Self-Regulation Questionnaire (Levesque et al., 2007). Using the question stem "The reason I would follow a healthy diet is...", participants rated items on a scale from 1 (not at all true) to 7 (very true). Four items were averaged to create the subscale of external Motivation for healthy eating (range 1-7). Higher scores on each subscale indicated higher external motivation for healthy eating.

This pilot study used a factorial design, with 16 conditions and typically 4 participants per condition. The study was designed with the intent to collapse across conditions for all analyses, such that the 8 conditions in which a given factor is ON would be compared to the 8 conditions in which that factor was OFF. Participants are counted multiple times in the table, such that the total number of participants in any ON/OFF condition pair will equal the full sample.

Participants responded to 10 items adapted from the Sallis Social Support for Diet Questionnaire (Sallis et al., 1987). Using the question stem "The other adult(s) in my household...", participants rated items on a scale from 1 (none) to 5 (very often), with 6 indicating "Not Applicable" (N/A; recoded as 1). Five items were summed to measure encouragement of healthy eating (e.g., "complimented me on changing my eating habits"; range 5-25), with higher scores indicating higher encouragement. This pilot study used a factorial design, with 16 conditions and typically 4 participants per condition. The study was designed with the intent to collapse across conditions for all analyses, such that the 8 conditions in which a given factor is ON would be compared to the 8 conditions in which that factor was OFF. Participants are counted multiple times in the table, such that the total number of participants in any ON/OFF condition pair will equal the full sample.

Participants completed the Sallis Social Support for Diet Questionnaire (Sallis et al., 1987). Using the question stem "The other adult(s) in my household...", participants rated items on a scale from 1 (none) to 5 (very often). 6 indicated "Not Applicable," which was recoded as 1 (none). Five items (e.g., "ate unhealthy foods in front of me") were summed to create the Discouragement of Healthy Eating subscale (range 5-25); higher scores indicated higher discouragement.

This pilot study used a factorial design, with 16 conditions and typically 4 participants per condition. The study was designed with the intent to collapse across conditions for all analyses, such that the 8 conditions in which a given factor is ON would be compared to the 8 conditions in which that factor was OFF. Participants are counted multiple times in the table, such that the total number of participants in any ON/OFF condition pair will equal the full sample.

Quality of the household relationship was measured using 5 items adapted from the Relationship Assessment Scale (Hendrick, 1988). Items assessed the quality of their relationship with the person who served as their household support partner in the Eatwell program (e.g., "How well does this person meet your needs") on a scale from 1 (Low) to 5 (High). Scores on the 5 items were averaged to calculate a Relationship Quality total score (range 1-5); higher scores indicated higher perceived relationship quality.

This pilot study used a factorial design, with 16 conditions and typically 4 participants per condition. The study was designed with the intent to collapse across conditions for all analyses, such that the 8 conditions in which a given factor is ON would be compared to the 8 conditions in which that factor was OFF. Participants are counted multiple times in the table, such that the total number of participants in any ON/OFF condition pair will equal the full sample.

Weight history was measured using an investigator developed questionnaire. Participants answered the following question about weight history in the past 6 months: "Which of these statements best describe what has happened to your weight during the past 6 months?" Answer choices included: (1) My weight has stayed the same; (2) I've been losing weight; (3) I've been gaining weight; or (4) My weigh has fluctuated a lot.

This pilot study used a factorial design, with 16 conditions and typically 4 participants per condition. The study was designed with the intent to collapse across conditions for all analyses, such that the 8 conditions in which a given factor is ON would be compared to the 8 conditions in which that factor was OFF. Participants are counted multiple times in the table, such that the total number of participants in any ON/OFF condition pair will equal the full sample.

Dietary restraint was measured using the Three Factor Eating Questionnaire (Cappelleri et al., 2009). For items #1-20, participants rated statements on a 4-point Likert scale from 1 (definitely true) to 4 (definitely false; reverse coded). Item 21 assessed overall restraint on an 8-point scale from 1 (no restraint) to 8 (total restraint), recoded such that 1-2=1; 3-4=2; 5-6=3; and 7-8=4 (so that all items ranged 1-4). Six items were summed to calculate a Restraint score (range = 6-24); higher scores indicated more restraint.

This pilot study used a factorial design, with 16 conditions and ~4 participants per condition. The study was designed with the intent to collapse across conditions for all analyses, such that the 8 conditions in which a given factor is ON would be compared to the 8 conditions in which that factor was OFF. Participants are counted multiple times in the table, such that the total number of participants in any ON/OFF condition pair will equal the full sample.

Uncontrolled eating was measured using the subscale of the Three Factor Eating Questionnaire - 21 item (Cappelleri et al., 2009). Responses ranged from 1 (definitely true) to 4 (definitely false). Items were reverse coded and summed to calculate an uncontrolled eating (range = 6-24), with higher scores indicating higher uncontrolled eating.

This pilot study used a factorial design, with 16 conditions and typically 4 participants per condition. The study was designed with the intent to collapse across conditions for all analyses, such that the 8 conditions in which a given factor is ON would be compared to the 8 conditions in which that factor was OFF. Participants are counted multiple times in the table, such that the total number of participants in any ON/OFF condition pair will equal the full sample.

Emotional eating was measured using the subscale of the Three Factor Eating Questionnaire - 21 item (Cappelleri et al., 2009). Responses ranged from 1 (definitely true) to 4 (definitely false). Six were reverse coded and summed to calculate an emotional eating (range = 6-24), with higher scores indicating higher emotional eating.

This pilot study used a factorial design, with 16 conditions and typically 4 participants per condition. The study was designed with the intent to collapse across conditions for all analyses, such that the 8 conditions in which a given factor is ON would be compared to the 8 conditions in which that factor was OFF. Participants are counted multiple times in the table, such that the total number of participants in any ON/OFF condition pair will equal the full sample.

A 13-item Food Frequency Questionnaire was adapted from similar measures (Rifas-Shiman et al., 2001). To measure intake for guideline 1 (i.e., fruits, vegetables, whole grains, and bean/ legumes ), participants rated how frequently they consumed these categories (4 items) during an average week over the past month (0=Never, 1=less than once per week, 2=once per week, 3=2-4 times/week, 4=nearly daily/daily, 5=greater than twice per day). A total guideline 1 score was calculated as the average of responses to the 4 items (range 0-5), where higher scores indicate more frequently eating fruits, vegetables, whole grains, and beans/legumes. This study used a factorial design, with 16 conditions (with ~4 participants) and was designed to collapse across conditions (i.e., comparing 8 conditions where factor is ON to 8 OFF conditions). Participants are counted multiple times in the table, such that the total number of participants in any ON/OFF condition pair will equal the full sample.

A 13-item Food Frequency Questionnaire was adapted from similar measures (Rifas-Shiman et al., 2001). To measure intake for guideline 2 (i.e., processed foods high in fat, starches, sugars), participants rated how frequently they consumed foods from these categories (6 items) during an average week over the past month (0=Never, 1=less than once per week, 2=once per week, 3=2-4 times/week, 4=nearly daily/daily, 5=greater than twice per day). A total guideline 2 score was calculated as the average of responses to the 6 items (range 0-5), where higher scores indicate more frequently eating processed foods. This study used a factorial design, with 16 conditions (with ~4 participants) and was designed to collapse across conditions (i.e., comparing 8 conditions where factor is ON to 8 OFF conditions). Participants are counted multiple times in the table, such that the total number of participants in any ON/OFF condition pair will equal the full sample.

A 13-item Food Frequency Questionnaire was adapted from similar measures (Rifas-Shiman et al., 2001). To measure intake for guideline 3 (i.e., red and processed meat), participants rated how frequently they consumed these categories (2 items) during an average week over the past month (0=Never, 1=less than once per week, 2=once per week, 3=2-4 times/week, 4=nearly daily/daily, 5=greater than twice per day). A total guideline 3 score was calculated as the average of responses to the 2 items (range 0-5), where higher scores indicate more frequently eating red and processed meats. This study used a factorial design, with 16 conditions (with ~4 participants) and was designed to collapse across conditions (i.e., comparing 8 conditions where factor is ON to 8 OFF conditions). Participants are counted multiple times in the table, such that the total number of participants in any ON/OFF condition pair will equal the full sample.

A 13-item Food Frequency Questionnaire was adapted from similar measures (Rifas-Shiman et al., 2001). To measure intake for guideline 4 (i.e., sugar-sweetened drinks), participants rated how frequently they consumed these drinks (1 item) during an average week over the past month (0=Never, 1=less than once per week, 2=once per week, 3=2-4 times/week, 4=nearly daily/daily, 5=greater than twice per day). Given intake for guideline 4 was assessed with only 1 item on the FFQ, the total guideline 4 score was the response to this single item (range 0-5), where higher scores indicate more frequently drinking sugar-sweetened drinks. This study used a factorial design, with 16 conditions (with ~4 participants) and was designed to collapse across conditions (i.e., comparing 8 conditions where factor is ON to 8 OFF conditions). Participants are counted multiple times in the table, such that the total number of participants in any ON/OFF condition pair will equal the full sample.

An adapted 8- item version of the Treatment Acceptability Questionnaire (Hunsley, 1993) was used to assess intervention acceptability. Eight questions probed their program experience and how helpful/acceptable they found various intervention components (e.g., "How effective do you think this program is?"). Responses ranged from 1 = no/low acceptability to 7 = high acceptability. A total score was calculated as the average across all 8 items (range 8-56) where higher scores indicate greater treatment acceptability.

This pilot study used a factorial design, with 16 conditions and typically 4 participants per condition. The study was designed with the intent to collapse across conditions for all analyses, such that the 8 conditions in which a given factor is ON would be compared to the 8 conditions in which that factor was OFF. Participants are counted multiple times in the table, such that the total number of participants in any ON/OFF condition pair will equal the full sample.

An adapted 8- item version of the Treatment Acceptability Questionnaire (Hunsley, 1993) was used to assess intervention acceptability. Eight questions probed their program experience and how helpful/acceptable they found various intervention components (e.g., "How effective do you think this program is?"). Responses ranged from 1 = no/low acceptability to 7 = high acceptability. A total score was calculated as the average across all 8 items (range 8-56) where higher scores indicate greater treatment acceptability.

This pilot study used a factorial design, with 16 conditions and typically 4 participants per condition. The study was designed with the intent to collapse across conditions for all analyses, such that the 8 conditions in which a given factor is ON would be compared to the 8 conditions in which that factor was OFF. Participants are counted multiple times in the table, such that the total number of participants in any ON/OFF condition pair will equal the full sample.

Two self-report items developed by the investigator assessed the goals of the selected household member at baseline: "On a scale of 1-100, how important is it that you adopt healthier eating habits right now?". Item 2 asked "On a scale of 1-100, how important is it that you help your household member adopt healthier eating habits right now?". For each item, household members responded on a scale from 0 - not important at all, 50 - about as important as most of the other things I would like to achieve now, to 100 - most important thing in my life now. Items were analyzed at individually, and each item ranged 0-100 where higher scores indicate higher importance of the associated goal.

Household members completed the same 13-item Food Frequency Questionnaire as the index participant (adapted from Rifas-Shiman et al., 2001) to measure dietary intake. Household members are presented with 13 categories of foods that are relevant for each of the cancer prevention dietary guidelines (e.g., "Fresh, frozen, or canned fruit (not dried or fruit juice)", "Red meats such as beef, pork, lamb"). They rated how frequently they consume each category during an average week over the past month. Scale is as follows: 0 = Never, 1 = less than per week, 2= once per week, 3 = 2-4 times per week, 4 = nearly daily or daily, 5 = greater than twice per day. The 13 items are then classified into the guideline they pertain to and total guidelines scores were calculated as the average of responses to all relevant items (range 0-5) where higher scores indicate more frequently eating items associated with that nutrition guideline.

Household members completed the same adapted 8- item version of the Treatment Acceptability Questionnaire (Hunsley, 1993) as index participants. This measured acceptability of the intervention. Household members were presented with 8 questions about their experience during the program and how helpful/acceptable they found various intervention components to be (e.g., "How effective do you think this program is?", "How trustworthy do you think your coach was?". Household members responded to each question on a 7-point Likert scale where 1 = no/low acceptability and 7 = high acceptability. A total score was calculated as the average across all 8 items (range 8-56) where higher scores indicate greater treatment acceptability.

Household members completed the same 13-item Food Frequency Questionnaire as the index participant (adapted from Rifas-Shiman et al., 2001) to measure dietary intake. To measure intake consistent with guideline 1 of the dietary cancer prevention guidelines (i.e., intake of fruits, vegetables, whole grains, and bean/ legumes ), household members rated how frequently they consumed these categories (4 items) during an average week over the past month. Scale was as follows: 0 = Never, 1 = less than once per week, 2= once per week, 3 = 2-4 times per week, 4 = nearly daily or daily, 5 = greater than twice per day. A total guideline 1 score was calculated as the average of responses to the 4 items (range 0-5), where higher scores indicate more frequently eating fruits, vegetables, whole grains, and beans/legumes.

Household members completed the same 13-item Food Frequency Questionnaire as the index participant (adapted from Rifas-Shiman et al., 2001) to measure dietary intake. To measure intake consistent with guideline 2 of the dietary cancer prevention guidelines (i.e., intake of processed foods high in fat, starches, or sugars), household members rated how frequently they consumed foods that fell into these categories (6 items) during an average week over the past month. Scale was as follows: 0 = Never, 1 = less than once per week, 2= once per week, 3 = 2-4 times per week, 4 = nearly daily or daily, 5 = greater than twice per day. A total guideline 2 score was calculated as the average of responses to the 6 items (range 0-5), where higher scores indicate more frequently eating processed foods high in far, starches, and sugars.

Household members completed the same 13-item Food Frequency Questionnaire as the index participant (adapted from Rifas-Shiman et al., 2001) to measure dietary intake. To measure intake consistent with guideline 3 of the dietary cancer prevention guidelines (i.e., intake of red and processed meats), household members rated how frequently they consumed red meats and processed meats (2 items) during an average week over the past month. Scale was as follows: 0 = Never, 1 = less than once per week, 2= once per week, 3 = 2-4 times per week, 4 = nearly daily or daily, 5 = greater than twice per day. A total guideline 3 score was calculated as the average of responses to the 2 items (range 0-5), where higher scores indicate more frequently eating red and processed meats.

Household members completed the same 13-item Food Frequency Questionnaire as the index participant (adapted from Rifas-Shiman et al., 2001) to measure dietary intake. To measure intake consistent with guideline 4 of the dietary cancer prevention guidelines (i.e., intake of sugar sweetened beverages), household members rated how frequently they consumed sugar sweetened beverages (1 item) during an average week over the past month. Scale was as follows: 0 = Never, 1 = less than once per week, 2= once per week, 3 = 2-4 times per week, 4 = nearly daily or daily, 5 = greater than twice per day. A total guideline 4 score was calculated as the response to this item (range 0-5), where higher scores indicate more frequently drinking sugar sweetened beverages.