The online supermarket study
| ISRCTN | ISRCTN13729526 |
|---|---|
| DOI | https://doi.org/10.1186/ISRCTN13729526 |
| Secondary identifying numbers | v1.0 |
- Submission date
- 26/02/2018
- Registration date
- 23/03/2018
- Last edited
- 10/08/2022
- Recruitment status
- No longer recruiting
- Overall study status
- Completed
- Condition category
- Nutritional, Metabolic, Endocrine
Plain English summary of protocol
Background and study aims
Poor diet is a risk factor for heart disease. Saturated fat (SFA) in food increases the type of cholesterol (LDL-cholesterol) that increases the chances of heart disease. Cutting down on food containing SFA, e.g. swapping butter for plant-based spreads, could help lower the risk of heart disease. Researchers are currently investigating new ways of reducing SFA in the population's diet. This study is an online shopping experiment to find out which are the best food swaps which achieve the greatest impact on SFA, and also the swaps which are most acceptable to people. The researchers are also interested in whether they can change purchases by changing the way foods choices are presented online.
Who can participate?
Healthy volunteers aged 18 and over
What does the study involve?
Participants do a 'pretend' shop in an online supermarket specially designed to conduct this kind of experiment. They are randomly allocated to one of for groups. One group is offered lower SFA swaps to the products they first select. In a second group the position of foods in the list which appears on screen is changed so that lower SFA options are positioned higher up. In the third group both of these interventions are applied together. The fourth group see the default version of the website with no swaps offered and a random order of the foods displayed in response to each search. The amount of SFA in the final basket is calculated for the four groups.
What are the possible benefits and risks of participating?
If successful, these strategies can be delivered at scale supporting current efforts to help people make lifestyle changes to lower their risk of chronic diseases. There are no direct benefits or risks involved in participating in this study, but the participants are reimbursed for their effort.
Where is the study run from?
University of Oxford (UK)
When is the study starting and how long is it expected to run for?
February 2018 to February 2019
Who is funding the study?
National Institute for Health Research (NIHR) (UK)
Who is the main contact?
Dr Dimitrios Koutoukidis
dimitrios.koutoukidis@phc.ox.ac.uk
Contact information
Scientific
Radcliffe Observatory Quarter
Woodstock Road
Oxford
OX2 6GG
United Kingdom
 ORCID ID |
0000-0002-1955-7234 |
|---|---|
| Phone | +44 (0)1865617767 |
| dimitrios.koutoukidis@phc.ox.ac.uk |
Study information
| Study design | Randomised controlled trial with a 2x2 factorial design |
|---|---|
| Primary study design | Interventional |
| Secondary study design | Randomised controlled trial |
| Study setting(s) | Internet/virtual |
| Study type | Prevention |
| Participant information sheet | Not available in web format, please use the contact details to request a patient information sheet |
| Scientific title | The effectiveness of individual-level and environmental-level interventions on food choices: an experimental online supermarket study |
| Study acronym | OLS |
| Study objectives | To investigate the magnitude of saturated fat change achieved in the shopping basket in response to an individual-level intervention and an environmental-level intervention, separately and in combination, compared to control (no intervention). |
| Ethics approval(s) | University of Oxford, Medical Sciences Interdivisional Research Ethics Committee, 08/02/2018, ref: R55722/RE001 |
| Health condition(s) or problem(s) studied | Food choices |
| Intervention | This study uses a bespoke virtual online supermarket shopping (OLS) platform, hosted by The University of Oxford, which emulates a real online supermarket for research purposes relating to food purchasing interventions. Participants will be randomly allocated to one of the following groups when shopping online: 1. Individual-level intervention: offering a swap to a product with less saturated fat (SFA) Swaps will be offered at point of selection i.e. when a participant selects an item to put in their shopping basket, if an alternative product exists that is lower in SFA within the same food category, the participant will be offered the chance to swap the item. Products offered as swaps will be within the same general price and weight range as the original item. 2. Environmental-level intervention: prominent positioning of lower SFA options This will apply to each list of foods offered to participants when searching for products. 3. A combination of individual- and environmental-level interventions This group will receive both interventions as described above. 4. Control Participants in this group will see the default version of the website with no swaps offered and a random order of the foods displayed in response to each search. |
| Intervention type | Behavioural |
| Primary outcome measure | Current primary outcome measure as of 20/07/2018: The difference in the saturated fat content of the final basket (measured in % of total energy) between each of the four trial arms Previous primary outcome measure: Difference in the saturated fat change of the final basket (measured in % of total energy) between each single intervention group and control; between combined intervention groups and each single intervention group; and between combined intervention groups and control |
| Secondary outcome measures | Current secondary outcome measures as of 20/07/2018: The following outcomes will be compared between each of the four trial arms: 1. Difference in the proportion of products with lower saturated fat in the final basket (%) 2. Difference in the overall cost of the final shopping basket (£) weighted for the size of the basket (g) 3. Difference in the total energy, energy density, sugars (% energy), and salt (g/100g) content of the shopping basket The following outcomes will be compared between the single individual-level intervention (swaps only) and the combined intervention arms: 4. Difference in % saturated fat content per swap accepted (% energy intake) 5. Difference in the proportion of swaps accepted out of those offered (%) 6. Difference in the proportion of swaps accepted out of those offered (%) by median observed change in saturated fat 7. Difference in the proportion of swaps accepted out of those offered (%) for (a) butter, margarine, and spreads, (b) cheese, (c) milk, (d) meat, and (e) sweets and desserts 8. Difference in the proportion of accepted swaps out of total shopping basket items (%) Previous secondary outcome measures: Difference between intervention vs control: 1. The proportion of products with lower saturated fat in the final basket (%) 2. % saturated fat content per swap accepted (% energy intake) 3. The proportion of swaps accepted out of those offered (%) 4. The proportion of accepted swaps out of total shopping basket items (%) 5. The overall cost of the final shopping basket (£) weighted for the size of the basket 6. The total energy, energy density, sugars (% energy) and salt (g/100g) content of the shopping basket |
| Overall study start date | 08/02/2018 |
| Completion date | 07/02/2019 |
Eligibility
| Participant type(s) | Healthy volunteer |
|---|---|
| Age group | Adult |
| Lower age limit | 18 Years |
| Sex | Both |
| Target number of participants | 1240 |
| Total final enrolment | 1240 |
| Key inclusion criteria | 1. UK adults, aged ≥18 years 2. Able to speak and read English 3. Willing and able to give informed consent for participation in the study 4. Being the main (or shared) grocery shopper for their household 5. Having access to a computer and Internet |
| Key exclusion criteria | Having any dietary restriction |
| Date of first enrolment | 26/03/2018 |
| Date of final enrolment | 29/06/2018 |
Locations
Countries of recruitment
- England
- United Kingdom
Study participating centre
Woodstock Road
Oxford
OX2 6GG
United Kingdom
Sponsor information
University/education
Research Services
Joint Research Office
Block 60, Churchill Hospital
Old Road, Headington
Oxford
OX3 7LE
England
United Kingdom
"ROR" |
https://ror.org/052gg0110 |
|---|
Funders
Funder type
Government
Government organisation / National government
- Alternative name(s)
- National Institute for Health Research, NIHR Research, NIHRresearch, NIHR - National Institute for Health Research, NIHR (The National Institute for Health and Care Research), NIHR
- Location
- United Kingdom
Results and Publications
| Intention to publish date | 07/02/2020 |
|---|---|
| Individual participant data (IPD) Intention to share | No |
| IPD sharing plan summary | Data sharing statement to be made available at a later date |
| Publication and dissemination plan | The study protocol will become available. The statistical analysis plan created prior to running the statistical analysis is available. Planned publication of the study results in a high-impact peer reviewed journal. |
| IPD sharing plan | The current data sharing plans for the study are unknown and will be made available at a later date. |
Study outputs
| Output type | Details | Date created | Date added | Peer reviewed? | Patient-facing? |
|---|---|---|---|---|---|
| Statistical Analysis Plan | version v1.0 | 13/07/2018 | 20/07/2018 | No | No |
| Results article | results | 07/06/2019 | 14/06/2019 | Yes | No |
| Protocol file | version 3.0 | 13/07/2018 | 10/08/2022 | No | No |
Additional files
Editorial Notes
10/08/2022: Uploaded protocol (not peer-reviewed) as an additional file.
14/06/2019: Publication reference and total final enrolment number added.
20/07/2018: The following changes were made to the trial record:
1. The recruitment end date was changed from 12/06/2018 to 29/06/2018.
2. The primary and secondary outcome measures were updated.
3. Uploaded statistical analysis plan.
16/04/2018: The target number of participants was changed from 500 to 1240.
