Impact on alcohol selection and online purchasing of changing the proportion of available non-alcoholic versus alcoholic drinks: a randomised controlled trial

Clarke, N ORCID: 0000-0003-2375-4510, Blackwell, A.K.M, Ferrar, J, De-Loyde, K, Pilling, M.A, Munafò, M.R, Marteau, T.M and Hollands, G.J (2023) 'Impact on alcohol selection and online purchasing of changing the proportion of available non-alcoholic versus alcoholic drinks: a randomised controlled trial.' PLoS Medicine, 20 (3). e1004193.

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Official URL: https://doi.org/10.1371/journal.pmed.1004193

Abstract

Background:- Increasing the availability of non-alcoholic options is a promising population-level intervention to reduce alcohol consumption, currently unassessed in naturalistic settings. This study in an online retail context aimed to estimate the impact of increasing the proportion of non-alcoholic (relative to alcoholic) drinks, on selection and purchasing of alcohol. Methods and results:- Adults (n = 737) residing in England and Wales who regularly purchased alcohol online were recruited between March and July 2021. Participants were randomly assigned to one of 3 groups: “25% non-alcoholic/75% alcoholic”; “50% non-alcoholic/50% alcoholic”; and “75% non-alcoholic/25% alcoholic,” then selected drinks in a simulated online supermarket, before purchasing them in an actual online supermarket. The primary outcome was the number of alcohol units selected (with intention to purchase); secondary outcomes included actual purchasing. A total of 607 participants (60% female, mean age = 38 years [range: 18 to 76]) completed the study and were included in the primary analysis. In the first part of a hurdle model, a greater proportion of participants in the “75% non-alcoholic” group did not select any alcohol (13.1%) compared to the “25% non-alcoholic” group (3.4%; 95% confidence interval [CI] −2.09, −0.63; p < 0.001). There was no evidence of a difference between the “75% non-alcoholic” and the “50% non-alcoholic” (7.2%) groups (95% CI 0.10, 1.34; p = 0.022) or between the “50% non-alcoholic” and the “25% non-alcoholic” groups (95% CI −1.44, 0.17; p = 0.121). In the second part of a hurdle model in participants (559/607) selecting any drinks containing alcohol, the “75% non-alcoholic” group selected fewer alcohol units compared to the “50% non-alcoholic” (95% CI −0.44, −0.14; p < 0.001) and “25% non-alcoholic” (95% CI −0.54, −0.24; p < 0.001) groups, with no evidence of a difference between the “50% non-alcoholic” and “25% non-alcoholic” groups (95% CI −0.24, 0.05; p = 0.178). Overall, across all participants, 17.46 units (95% CI 15.24, 19.68) were selected in the “75% non-alcoholic” group; 25.51 units (95% CI 22.60, 28.43) in the “50% non-alcoholic” group; and 29.40 units (95% CI 26.39, 32.42) in the “25% non-alcoholic” group. This corresponds to 8.1 fewer units (a 32% reduction) in the “75% non-alcoholic” compared to the “50% non-alcoholic” group, and 11.9 fewer alcohol units (41% reduction) compared to the “25% non-alcoholic” group; 3.9 fewer units (13% reduction) were selected in the “50% non-alcoholic” group than in the “25% non-alcoholic” group. For all other outcomes, alcohol selection and purchasing were consistently lowest in the “75% non-alcoholic” group. Study limitations include the setting not being entirely naturalistic due to using a simulated online supermarket as well as an actual online supermarket, and that there was substantial dropout between selection and purchasing. Conclusions:- This study provides evidence that substantially increasing the proportion of non-alcoholic drinks—from 25% to 50% or 75%—meaningfully reduces alcohol selection and purchasing. Further studies are warranted to assess whether these effects are realised in a range of real-world settings.

Item Type: Article
Note:

Trial registration: ISRCTN: 11004483; OSF: https://osf.io/qfupw.

Keywords: alcohol consumption, alcoholism, beer, wine, medical risk factors, randomised controlled trials, food
Divisions: School of Sciences
Related URLs:
Date Deposited: 31 Mar 2023 16:54
Last Modified: 17 Oct 2024 10:38
ISSN: 1549-1277
URI / Page ID: https://researchspace.bathspa.ac.uk/id/eprint/15318
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