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The goal of the proposed study is to apply experimental economics in an online grocery store shopping model to examine the effects of pricing on hypothetical food purchases
Participants will be lean and overweight primary grocery shoppers aged 18 years and older. Participants will be considered lean if their body mass index (BMI = kg/m2) is less than 29.9, overweight if their BMI is greater than or equal to 30.12 To meet eligibility for the study, participants must be the guardian of a child at least 2 years or older, do the primary grocery shopping for the family, they must also report being weekly household grocery shoppers, and purchase the majority of their household's groceries once a week.
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| Measure | Description | Time Frame |
|---|---|---|
| Change in Energy Purchased as a Result of Taxes. | Change in total calories as a result of taxes of 12.5% and 25%. | Study Completion |
| Change in Energy Purchased as a Result of Subsidies | Change in total calories as a result of subsidies of 12.5% and 25%. | Study Completion |
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Inclusion Criteria:
18 or older primary shopper in the household, at least one child over 2 years of age
Exclusion Criteria:
eating disorders, not liking study foods
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Lean and overweight Low and high socioeconimic status primary grocery shopper
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| Name | Affiliation | Role |
|---|---|---|
| Leonard H Epstein, PhD | University at Buffalo | Principal Investigator |
| Facility | Status | City | State | ZIP | Country | Contacts |
|---|---|---|---|---|---|---|
| University at Buffalo | Buffalo | New York | 14214 | United States |
| PubMed Identifier | Type | Citation | Retractions |
|---|---|---|---|
| 29656049 | Derived | Epstein LH, Paluch RA, Carr KA, Temple JL, Bickel WK, MacKillop J. Reinforcing value and hypothetical behavioral economic demand for food and their relation to BMI. Eat Behav. 2018 Apr;29:120-127. doi: 10.1016/j.eatbeh.2018.03.008. Epub 2018 Apr 3. | |
| 26145274 | Derived | Epstein LH, Finkelstein E, Raynor H, Nederkoorn C, Fletcher KD, Jankowiak N, Paluch RA. Experimental analysis of the effect of taxes and subsides on calories purchased in an on-line supermarket. Appetite. 2015 Dec;95:245-51. doi: 10.1016/j.appet.2015.06.020. Epub 2015 Jul 3. |
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Interested eligible participants were screened and offered to start the study.
Recruitment in the Western New York Area targeted primary household grocery shoppers through the local community during 2011-2013.
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| ID | Title | Description |
|---|---|---|
| FG000 | Online Grocery | All participants completed a baseline session where behavioral measures of delay discounting, relative reinforcing value and relative reinforcing efficacy were measured. Participants then completed five shopping sessions under various price conditions. Age and Body Mass Index were measured at the end of the six session study. |
| Title | Milestones | Reasons Not Completed | ||||||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Overall Study |
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Age and Body Mass Index (BMI) were measured at the end of the study; therefore 5 participants were lost to follow up and the baseline measures are reported on 212 participants.
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| ID | Title | Description |
|---|---|---|
| BG000 | Lean Participants | Participants whose baseline BMI is less than 25. All participants completed a baseline session where behavioral measures of delay discounting, relative reinforcing value and relative reinforcing efficacy were measured. Participants then completed five shopping sessions under various price conditions. Age and Body Mass Index were measured at the end of the six session study; therefore, 5 participants were lost to follow up and no age or body mass index are reported for these participants. |
| Units | Counts |
|---|---|
| Participants |
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| Title | Description | Population Description | Parameter Type | Dispersion Type | Unit of Measure | Calculate Percentage | Denominator Units Selected | Denominators | Classes |
|---|---|---|---|---|---|---|---|---|---|
| Age, Continuous | Mean |
| Type | Title | Description | Population Description | Reporting Status | Anticipated Posting Date | Parameter Type | Dispersion Type | Unit of Measure | Calculate Percentage | Time Frame | Units Analyzed | Denominator Units Selected | Arm/Group Information | Denominators | Classes | Analyses | |||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Primary | Change in Energy Purchased as a Result of Taxes. | Change in total calories as a result of taxes of 12.5% and 25%. | Data is reported for 199 participants. Out of 217 participants who started the study, 5 participants were lost to follow up, 1 participant shopped in the same store twice, 2 participants had conditions that would affect shopping, 2 participants did not report minority status and 8 male participants were excluded due to the small sample number. | Posted | Least Squares Mean | Standard Error | Total Calories Purchased | Study Completion |
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Adverse Events were collected at each of six study sessions scheduled one week apart.
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| ID | Title | Description | Deaths (Affected) | Deaths (At Risk) | Serious Events (Affected) | Serious Events (At Risk) | Other Events (Affected) | Other Events (At Risk) |
|---|---|---|---|---|---|---|---|---|
| EG000 | Online Grocery | All participants completed a baseline session where behavioral measures of delay discounting, relative reinforcing value and relative reinforcing efficacy, along with the Three Factor Eating Questionnaire were measured. Participants then completed five shopping sessions under various price conditions. Age and Body Mass Index were measured at the end of the six session study. |
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| Title | Organization | Phone | Extension | |
|---|---|---|---|---|
| Leonard H. Epstein | SUNYBuffalo | 716-829-3400 | ckk@buffalo.edu |
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| 24311480 | Derived | Epstein LH, Jankowiak N, Fletcher KD, Carr KA, Nederkoorn C, Raynor HA, Finkelstein E. Women who are motivated to eat and discount the future are more obese. Obesity (Silver Spring). 2014 Jun;22(6):1394-9. doi: 10.1002/oby.20661. Epub 2013 Dec 6. |
| BG001 | Overweight/Obese Participants | Participants whose baseline BMI is greater than or equal to 25. All participants completed a baseline session where behavioral measures of delay discounting, relative reinforcing value and relative reinforcing efficacy were measured. Participants then completed five shopping sessions under various price conditions. Age and Body Mass Index were measured at the end of the six session study; therefore, 5 participants were lost to follow up and no age or body mass index are reported for these participants. |
| BG002 | Total | Total of all reporting groups |
| years |
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| Gender | Count of Participants | Participants |
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| Ethnicity (NIH/OMB) | Count of Participants | Participants |
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| Race (NIH/OMB) | Count of Participants | Participants |
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| Body Mass Index | Body Mass Index (BMI) was measured at the end of the sixth study session; therefore, 5 participants were lost to follow up and this is measured with 212 participants. | Mean | Standard Deviation | kg/m^2 |
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| Relative Reinforcing Value High Energy Dense Foods (RRV HED) | RRV was assessed using a computer program where subjects earned points toward food. Participants earned a point by clicking a mouse to meet schedule requirements, i.e. 20 clicks earned one portion of food on schedule one. Each subsequent schedule had double the requirements of the previous schedule. Participants were rewarded with their preferred food each time they completed the schedule requirements. The session ended when participants no longer wished to earn points towards food. | Mean | Standard Deviation | Highest Response schedule completed |
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| Relative Reinforcing Value Low Energy Dense Foods (RRV LED) | RRV was assessed using a computer program where subjects earned points toward food. Participants earned a point by clicking a mouse to meet schedule requirements, i.e. 20 clicks earned one portion of food on schedule one. Each subsequent schedule had double the requirements of the previous schedule. Participants were rewarded with their preferred food each time they completed the schedule requirements. The session ended when participants no longer wished to earn points towards food. | Mean | Standard Deviation | Highest response schedule completed |
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| Delay Discounting $10 reward (DD 10) | The delay discounting task involved allowing participants to make choices between smaller immediate monetary rewards and a larger, fixed, delayed reward. Participants completed both increasing amount of the immediate reward, and decreasing amount of the immediate reward, in a randomized order, over a series of time delays (1 day, 2 days, etc). An indifference point was calculated as the amount of immediate reward that was equal to the delayed reward. From this area under the curve, or indifference proportion*delay proportion, was calculated, leading the a range of scores between 0 and 1. | Mean | Standard Deviation | indifference proportion*delay proportion |
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| Delay Discounting $100 reward (DD 100) | The delay discounting task involved allowing participants to make choices between smaller immediate monetary rewards and a larger, fixed, delayed reward. Participants completed both increasing amount of the immediate reward, and decreasing amount of the immediate reward, in a randomized order, over a series of time delays (1 day, 2 days, etc). An indifference point was calculated as the amount of immediate reward that was equal to the delayed reward. From this area under the curve, or indifference proportion*delay proportion, was calculated, leading the a range of scores between 0 and 1. | Mean | Standard Deviation | indifference proportion*delay proportion |
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| OG001 | Lean Participants | Participants with BMI less than 25. |
| OG002 | Overweight/Obese Participants | Participants with BMI greater than or equal to 25. |
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| Primary | Change in Energy Purchased as a Result of Subsidies | Change in total calories as a result of subsidies of 12.5% and 25%. | Data is reported for 199 participants. Out of 217 participants who started the study, 5 participants were lost to follow up, 1 participant shopped in the same store twice, 2 participants had conditions that would affect shopping, 2 participants did not report minority status and 8 male participants were excluded due to the small sample number. | Posted | Least Squares Mean | Standard Error | Total Calories Purchased | Study Completion |
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| 0 |
| 217 |
| 0 |
| 217 |
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| Calories Purchased in the Subsidy 25 Condition |
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