ABSTRACT: INTRODUCTION:Since 2012, England has an annual "Stoptober" campaign for collective smoking cessation. Our aim was to assess (1) overall impact of the Stoptober campaign on quit attempts over its first 6 years, (2) consistency of impact over the campaign years, and (3) the role of the campaign budget. METHODS:We used data of 51 399 adult smokers and ex-smokers in 132 repeat cross-sectional monthly surveys in England, 2007-2017. In a quasiexperimental design, adjusted logistic regression analyses compared past-month quit attempt rate between (1) October and other months in the year, between 2007-2011 and 2012-2017; (2) October and other months, across years 2012-2017; and (3) October and other months, between high-budget (2012-2015) and low-budget Stoptober campaigns (2016-2017). Bayes factors (BF) differentiated insensitive data and absence of an effect. RESULTS:(1) In 2012-2017, quit attempts were more prevalent in October versus other months (odds ratio [OR]: 1.24, 95% confidence interval [CI]: 1.00 to 1.53), whereas similar in 2007-2011 (OR: 0.95, 95% CI: 0.76 to 1.18; BF = 0.2); data were somewhat insensitive but supported this difference (OR: 1.30, 95% CI: 0.97 to 1.75; BF = 2.1). (2) In 2012-2017, quit attempt prevalence ranged from 3.1% to 8.5% in October and 5.0% to 7.3% in other months. The difference between October and other months was large in 2012 (absolute unadjusted difference of 3.3%; OR: 1.92, 95% CI: 1.23 to 2.98) and 2015 (3.1%; OR: 1.84, 95% CI: 1.14 to 2.95), but small in 2013-2014 and 2016-2017 (0.36 < BF < 1.02). (3) Data were somewhat insensitive but supported interaction with campaign budget (OR: 1.50, 95% CI: 0.92 to 2.44; BF = 2.2). DISCUSSION:In 2012-2017, there appears to have been an increase in past-month quit attempts during October in England. The increase was inconsistent across Stoptober campaigns and appears to have been greater when the campaign budget was higher. IMPLICATIONS:Over the first 6 years of Stoptober campaigns, there appears to have been an overall increase in past-month quit attempts during October in England, and the data imply that a sufficiently high budget contributes to greater impact of the Stoptober campaign. These findings encourage the further spread of the Stoptober campaign to other countries. Future research should clarify how increased quit attempts as a consequence of Stoptober translate into quit success and which of Stoptober's ingredients were most important in increasing quit attempts, especially among vulnerable groups.
