Referral to Slimming World in UK Stop Smoking Services (SWISSS) versus stop smoking support alone on body weight in quitters: results of a randomised controlled trial

Deborah Lycett, Paul Aveyard, Andrew Farmer, Amanda Lewis, Marcus Munafò

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    3 Citations (Scopus)
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    INTRODUCTION: Most people who stop smoking gain weight. Dietary modification may seem an obvious solution, but food restriction may increase cigarette craving and smoking relapse.

    TRIAL DESIGN: An unblinded parallel randomised controlled trial.

    METHODS: Participants were adult smokers with a body mass index greater or equal to 23 kg/m2. Setting was National Health Service commissioned Stop Smoking Services, interventions were referral to a commercial weight management programme, plus stop smoking support (treatment group), compared with stop smoking support alone (control group). Objective was to compare weight change between interventions in smoking abstainers and not abstinent rates in all. Primary outcome was change in weight (kg) at 12 weeks. Randomisation sequence was computer generated and concealed until allocation.

    RESULTS: Seventy-six participants were recruited, 37 were randomised to the treatment group and 39 to the control group. Change in weight was analysed in long-term abstainers (13 treatment, 14 control) only because the aim was to prevent weight gain associated with smoking cessation. Abstinence was analysed on an intention-to-treat basis (37 treatment, 39 control). At 12 weeks weight gain was less in the treatment than the control group with an adjusted mean difference of -2.3 kg 95% CI (-4.4 to -0.1). Craving scores were lower (Mood and Physical Symptoms Scale craving domain -1.6 (-2.7 to -0.5)) and quit rates were higher in the treatment than the control group (32% vs 21%), although the trial was not powered to superiority in cravings and quit rates. No adverse events or side effects were reported.

    CONCLUSION: In people who are obese and want to quit smoking, these data provide modest encouragement that providing weight management at the time of quitting may be helpful. Those who are not obese, but who are informed about potential weight gain during their quit attempt, were uninterested in a weight management programme.


    Original languageEnglish
    Article numbere032271
    Number of pages10
    JournalBMJ Open
    Issue number1
    Publication statusPublished - 26 Jan 2020

    Bibliographical note

    This is an open access article distributed in accordance with the Creative Commons Attribution 4.0 Unported (CC BY 4.0) license, which permits others to copy, redistribute, remix, transform and build upon this work for any purpose, provided the original work is properly cited, a link to the licence is given, and indication of whether changes were made.


    • obesity
    • smoking
    • weight

    ASJC Scopus subject areas

    • Medicine(all)


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