D'Mello, Kimberly2024-09-042024-09-042024-09-042024-07-24https://hdl.handle.net/10012/20955Background: E-cigarettes are a popular method of smoking cessation assistance. However, few studies have examined whether e-cigarettes serve as a substitute for other effective smoking cessation assistance, including how population-level changes in the use of e-cigarettes for smoking cessation compare to changes in the use of nicotine replacement therapy (NRT), prescription pharmacological therapies, and other smoking cessation methods. Objectives: To examine changes in the types of cessation assistance used by people trying to quit smoking over time, including: 1) the use of e-cigarettes in a quit attempt and 2) the use of other effective methods of cessation assistance. Methods: The study protocol has been preregistered (https://osf.io/jpnqc). Data are from the 2016, 2018, and 2020 Waves of the ITC Four Country Smoking and Vaping Survey. Respondents were recruited by commercial panel firms in each country who were ≥ 18 years of age and, who currently smoke, recently quit smoking, and/or currently vape. Analyses examined the use of cessation assistance among the 14,551 observations from participants with an attempt to quit smoking in the past 12-months since survey date (CA=4,880; US=2,917; EN= 4,846; AU=1,898). Repeat cross-sectional analyses were conducted using generalized estimating equations stratified by country. Results: Across all countries, e-cigarettes (29.9%) and nicotine replacement therapies (NRT; 29.8%) were the most commonly reported categories of cessation assistance used in a previous quit attempt, followed by self–help services (17.8%), and prescription pharmacological therapies (12.6%). Overall, more than half (59.4%) of respondents used ‘any’ form of effective cessation assistance (including e-cigarettes). E-cigarette use increased in Australia from 2016 (11.1%) to 2020 (25.1%; OR=2.29, 95% CI=1.37-3.82, p=.002). In England, e-cigarette use increased from 2016 (37.1%) to 2018 (46.7%; OR=1.40, 95% CI=1.13-1.73, p=.002), and had no changes over time in Canada or the US. Use of other effective cessation methods (with and without e-cigarettes) had no changes over time in all countries, excluding Canada. In Canada, use of ‘any’ form of effective cessation assistance (including e-cigarettes) decreased from 2016 (64.0%) to 2020 (58.9%; OR=0.75, 95% CI=0.61-0.93, p=.010). Conclusion: Overall, there were strikingly similar rates of effective cessation assistance used across all four countries, despite differences in e-cigarette use and regulatory environments. While e-cigarettes are a popular choice of cessation method, there was little evidence that trends in use of e-cigarettes contributed to changes in the use of ‘any’ effective form of cessation assistance. The extent of ‘substitution’ between individual quit methods at the population-level was not directly assessed in this study; however, there was some evidence consistent with substitution for e-cigarettes and use of prescription therapies such that, the use of prescription therapies increased in England as the use of e-cigarettes as a quit method decreased, with the inverse trend in Australia; and little to no changes in the US and Canada.envapingsmokingsmoking cessatione-cigarettesMaster Thesis