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

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De-Loyde, Katie 


<jats:sec id="sec001"> jats:titleBackground</jats:title> jats:pIncreasing 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.</jats:p> </jats:sec> <jats:sec id="sec002"> jats:titleMethods and results</jats:title> jats:pAdults (jats:italicn</jats:italic> = 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.</jats:p> jats:pA 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; jats:italicp</jats:italic> < 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; jats:italicp</jats:italic> = 0.022) or between the “50% non-alcoholic” and the “25% non-alcoholic” groups (95% CI −1.44, 0.17; jats:italicp</jats:italic> = 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; jats:italicp</jats:italic> < 0.001) and “25% non-alcoholic” (95% CI −0.54, −0.24; jats:italicp</jats:italic> < 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; jats:italicp</jats:italic> = 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.</jats:p> jats:pFor all other outcomes, alcohol selection and purchasing were consistently lowest in the “75% non-alcoholic” group.</jats:p> jats:pStudy 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.</jats:p> </jats:sec> <jats:sec id="sec003"> jats:titleConclusions</jats:title> jats:pThis 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.</jats:p> </jats:sec> <jats:sec id="sec004"> jats:titleTrial registration</jats:title> jats:pISRCTN: <jats:ext-link xmlns:xlink="" ext-link-type="uri" xlink:href="" xlink:type="simple">11004483</jats:ext-link>; OSF: <jats:ext-link xmlns:xlink="" ext-link-type="uri" xlink:href="" xlink:type="simple"></jats:ext-link>.</jats:p> </jats:sec>



Research Article, Biology and life sciences, Medicine and health sciences, Social sciences, Research and analysis methods

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PLOS Medicine

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Public Library of Science (PLoS)
Wellcome (206853/Z/17/Z)
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