Condition category
Not Applicable
Date applied
12/10/2020
Date assigned
20/10/2020
Last edited
20/10/2020
Prospective/Retrospective
Prospectively registered
Overall trial status
Ongoing
Recruitment status
Recruiting

Plain English Summary

Background and study aims
Drinking too much alcohol can lead to the development of many health conditions, including some cancers and heart disease. One possible way of helping people reduce their alcohol consumption is to reduce the sizes of the containers – bottles and glasses – in which alcohol is sold and served. It is known that smaller bottles can help people drink less wine at home and smaller glasses help people drink less wine in restaurants, but there is uncertainty about how combining smaller bottles with smaller glasses affects how much wine people drink. The aim of this study is to find out whether drinking a fixed volume of wine in smaller versus standard bottle sizes using smaller versus larger glasses reduces consumption at home.

Who can participate?
Households in the UK that drink at least two standard bottles (75 cl) of wine a week

What does the study involve?
During each of two 14-day intervention periods, 238 households in the UK are requested to purchase a pre-set volume of wine – based on their baseline self-reported weekly consumption – in either 75 cl or 37.5 cl bottles, in a random order. Households order their wine online and intervention periods are separated by a ‘usual behaviour’ period lasting up to 3 weeks, to allow households to finish any remaining wine from their first order. Households also receive either small (290 ml) or large (350 ml) glasses, chosen at random, from which to drink the wine during both intervention periods. On days 7 and 14 of each of the two intervention periods, households are requested to send information regarding the date each bottle was opened and finished, and who drank from it, as well as photographs of all their study wine bottles and wine glasses, with each bottle weighed and photographed separately on study scales.

What are the possible benefits and risks of participating? 
The findings of this study will provide the best estimate to date of the impact of bottle size and glass size, singly and in combination, on wine consumed at home. This study is considered to be low risk and no adverse consequences are expected.

Where is the study run from?
The Behaviour and Health Research Unit at the University of Cambridge (UK)

When is the study starting and how long is it expected to run for?
June 2020 to July 2021

Who is funding the study?
The Wellcome Trust (UK)

Who is the main contact?
Prof. Theresa Marteau
tm388@medschl.cam.ac.uk

Trial website

Contact information

Type

Scientific

Primary contact

Prof Theresa Marteau

ORCID ID

Contact details

Behaviour and Health Research Unit
University of Cambridge
Institute of Public Health
Forvie Site
Robinson Way
Cambridge
CB2 0SR
United Kingdom
+44 (0)1223 762542
bcbd.administrator@medschl.cam.ac.uk

Additional identifiers

EudraCT number

Nil known

ClinicalTrials.gov number

Nil known

Protocol/serial number

Nil known

Study information

Scientific title

Impact of bottle size and glass size on wine consumption at home

Acronym

Study hypothesis

The aims of the proposed study are to assess the impact of wine bottle size and wine glass size, singly and in combination, on (a) volume of wine consumed at home and (b) rate of consumption. The specific hypotheses are:
1. Less wine is consumed at home from smaller bottles than from larger bottles
2. Less wine is consumed at home from smaller glasses than from larger glasses
3. Less wine is consumed at home from smaller wine bottles using smaller wine glasses than from larger wine bottles using larger wine glasses

Ethics approval

Approved 07/10/2020, University of Cambridge Psychology Research Ethics Committee (School of the Biological Sciences, 17 Mill Lane, Cambridge, CB2 1RX, UK; + 44 (0) 1223 766894; Cheryl.Torbett@admin.cam.ac.uk), ref: PRE.2020.098

Study design

Mixed between and within-subjects study, with glass size treated as a between-subjects factor and bottle size as a within-subjects factor

Primary study design

Interventional

Secondary study design

Randomised controlled trial

Trial setting

Home

Trial type

Prevention

Patient information sheet

Not available in web format, please use the contact details to request a participant information sheet

Condition

Alcohol consumption

Intervention

General population households will be exposed to two interventions comprising i) two different bottles sizes (within-subjects factor), randomized in their order of presentation and separated by a ‘usual behaviour’ period, and ii) one of two different glass sizes (between-subjects factor).

Bottle size
The two conditions comprise purchasing a given quantity of wine, sub-divided into bottles of one of two different sizes: 
1. 75 cl
2. 37.5 cl

Each of the two intervention periods will last two weeks (14 days), with an intervening ‘usual behaviour’ period of a maximum of three weeks, with exact duration determined by how long it takes each household to finish the wine ordered during the first intervention period. 
During each of two 14-day intervention periods, participants will be requested to purchase online three weeks’ worth of wine (based on their self-reported baseline consumption) in their allocated bottle size. The total volume of wine purchased will be the same across both intervention periods. In order to confirm they have ordered the appropriate wines (amount and size), participants will be requested to send a copy of the order to the research team.

Glass size
Households will also be randomised to receive either:
1. Small glasses (290 ml) or
2. Large glasses (350 ml) glasses
Wine purchased for the study will be drunk in one of two possible glass sizes. Both sizes of glass will be of the same design (Royal Leerdam Bouquet). Households will receive a set of glasses through the post – with the exact number depending on the number of wine drinkers within a household – to use when drinking any study wine.

Participants will be sent labels to stick on their study wine bottles to record the date each bottle was opened and finished, the number of people, including non-household members, who drank from each bottle, and the amount of non-study wine consumed at home. Participants will also be asked to rate their experience of drinking wine from each bottle size. They will be prompted to send close-up photographs (via email or WhatsApp) of all their labelled study wine bottles twice during each intervention period: at 7 days and 14 days after receipt of the study wine bottles. All bottles – whether unopened, partially full, or empty – will be photographed separately on provided study scales, so that both the label on the bottle and the number on the scales (i.e., the weight of the bottle) are clearly visible. Households will also be asked to send photographs of the wine glasses they used on days 7 and 14 of each intervention period.

Randomization to the order in which each wine in each bottle size is purchased (within-subject factor), as well as the glass size to use for the duration of the study (between-subjects factor), will occur in Qualtrics, an on‐line survey platform, during the completion of a baseline online questionnaire.

Intervention type

Behavioural

Phase

Drug names

Primary outcome measure

Volume of study wine consumed (in millilitres) during each intervention period for each bottle-glass size combination, estimated through returned photographs of all study wine bottles purchased.

Amounts consumed from opened bottles will be estimated from photographs of the bottles being weighted on provided study scales. Estimates will be based on the following procedures:
1. Three of each of the bottles on the study wine list (i.e. 66 bottles: 33 x 75 cl and 33 x 37.5 cl bottles) will be weighed when full in advance of the study commencing. Any variations in the amount of liquid in the bottles of the same wine or the weight of the empty bottle will be reported, and the average value will be used in all study calculations.
2. The weight of 1cl of wine will be estimated and used to calculate the weight of the wine in any partially full bottle of either size. 
3. The observed weight of the partially full bottle will be subtracted from the weight of the full bottle to give an estimate of the weight of the consumed wine.
4. The validity of the assumptions informing steps 1-3 above will be checked using four selected wines (those with the highest and lowest ABV) in each of 75 cl and 37.5 cl bottle sizes, weighing both full and empty bottles.

Primary analysis
Regression analysis will be used to predict wine consumption (in ml) at 14 days from each bottle size with each glass size. Analyses will control for the following covariates:
1. In-home consumption of non‐study wine (in millilitres) by the household during each of the two 14‐day intervention periods, assessed by self‐reports on bottle labels
2. Use of non-study wine glasses assessed by photographs and self-report
3. Guest consumption of study wine (in millilitres) during each of the two 14‐day intervention periods, assessed by self‐reports on bottle labels
4. Out‐of‐home consumption (in millilitres) by household members during each intervention period, assessed by self‐report
5. Amount of other alcohol (non-wine) consumed (in millilitre) by household members in and outside the home, during each intervention period, assessed by self-report
6. Number of wine drinkers in the household
7. Duration (in days) of ‘usual behaviour’ period
8. Baseline consumption (in millilitres) of wine per week, self‐reported
9. Price per litre of all ordered wine
10. Awareness of study aim, assessed in the end‐of‐study self-report questionnaire
11. Mitigating factors i.e. any noteworthy events or circumstances external to the study, self‐reported as having increased or decreased wine consumption during each intervention period

Measurements will be conducted on Day 7 and Day 14 of the first intervention period (i.e. 1 week and 2 weeks after the beginning of the study), as well as on Day 7 and Day 14 of the second intervention period (i.e. 3 weeks and 4 weeks after the beginning of the study; or 4 weeks and 5 weeks after the beginning of the study; or 5 weeks and 6 weeks after the beginning of the study or 6 weeks and 7 weeks after the beginning of the study, depending on the duration of the ‘usual behaviour’ period which will last a maximum of 3 weeks).

Secondary outcome measures

The mean number of days taken to consume each 1.5 litres of wine during each intervention period with each bottle-glass size combination, estimated from the start and finish dates reported on submitted photographs.

Secondary analysis
Regression analysis will be used to predict the time taken (in days) to consume each unit of 1.5 litres of wine from each bottle size with each glass size. Analyses will control for all specified covariates.

Measurements will be conducted on Day 7 and Day 14 of the first intervention period (i.e. 1 week and 2 weeks after the beginning of the study), as well as on Day 7 and Day 14 of the second intervention period (i.e. 3 weeks and 4 weeks after the beginning of the study; or 4 weeks and 5 weeks after the beginning of the study; or 5 weeks and 6 weeks after the beginning of the study or 6 weeks and 7 weeks after the beginning of the study, depending on the duration of the ‘usual behaviour’ period which will last a maximum of 3 weeks).

Overall trial start date

10/06/2020

Overall trial end date

30/09/2021

Reason abandoned (if study stopped)

Eligibility

Participant inclusion criteria

Eligible households are those in which adult members meet the following criteria:
1. Self-report that they collectively drink at least 2 x 75 cl bottles of wine (1.5 litres) a week
2. Usually purchase wine online or are willing to purchase wine online
3. Are willing to consume wine(s) exclusively from the study wine list and order a total of approximately 6 weeks’ worth of wine
4. Be prepared to drink all study wine (including both red and white) from the study wine glasses
5. Are in possession of a smartphone or similar device from which to send photographs of wine bottles and wine glasses
6. Do not take medications for which there is a recommendation against alcohol consumption
7. Are not pregnant or are planning on becoming pregnant during the study period
8. Do not have a history of becoming ill after alcohol consumption
9. Do not have a history of alcoholism or a serious mental illness (including paranoid and other psychotic disorders, bipolar disorders and schizoaffective disorders)

Participant type

Healthy volunteer

Age group

Adult

Gender

Both

Target number of participants

The study will involve 238 households

Participant exclusion criteria

Households with adult household members with the following characteristics will be excluded:
1. Self-report drinking less than 2 x 75cl bottles a week, at the household level
2. Take medications for which there is a recommendation against alcohol consumption
3. Have a history of becoming ill after alcohol consumption, requiring hospitalisation
4. Have a history of alcoholism or a serious mental illness (including paranoid and other psychotic disorders, bipolar disorders and schizoaffective disorders)
5. Are pregnant or plan on becoming pregnant during the study period

Recruitment start date

30/10/2020

Recruitment end date

30/05/2021

Locations

Countries of recruitment

United Kingdom

Trial participating centre

University of Cambridge
Behaviour and Health Research Unit Institute of Public Health Forvie Site Robinson Way
Cambridge
CB2 0SR
United Kingdom

Sponsor information

Organisation

University of Cambridge

Sponsor details

Cambridge Biomedical Campus
Clifford Allbutt Building
Bay 13
Hills Road
Cambridge
CB2 OAH
United Kingdom
+44 (0)1223 333543
croenquiries@admin.cam.ac.uk

Sponsor type

University/education

Website

http://www.cam.ac.uk/

Funders

Funder type

Research organisation

Funder name

Wellcome Trust

Alternative name(s)

Wellcome, The Wellcome Trust, WT

Funding Body Type

private sector organisation

Funding Body Subtype

International organizations

Location

United Kingdom

Results and Publications

Publication and dissemination plan

1. The protocol will be made available online on the Open Science Framework.
2. The researchers plan to write up their findings and submit them to a scientific journal for peer review and publication in October 2021.

IPD sharing statement
Data will be made available on the Open Science Framework and will remain there with no plans to remove it. Requests for data should be made to Professor Theresa Marteau (tm388@medschl.cam.ac.uk) who will provide a link to the anonymised dataset.

Intention to publish date

30/10/2021

Participant level data

Stored in repository

Basic results (scientific)

Publication list

Publication citations

Additional files

Editorial Notes

13/10/2020: Trial's existence confirmed by University of Cambridge Psychology Research Ethics Committee.