Associations between nicotine vaping uptake and cigarette smoking cessation vary by smokers' plans to quit: longitudinal findings from the International Tobacco Control Four Country Smoking and Vaping Surveys

Background and Aims Most population studies that evaluate the relationship between nicotine vaping and cigarette cessation focus on limited segments of the smoker population. We evaluated vaping uptake and smoking cessation considering differences in smokers' plans to quit. Design Longitudinal International Tobacco Control (ITC) Four Country Smoking and Vaping Surveys were conducted in 2016, 2018 and 2020. Setting This study was conducted in the United States, Canada, England and Australia. Participants Participants of this study were adult daily cigarette smokers who had not vaped in the past 6 months at baseline and had participated in two or more consecutive waves of the ITC Four Country Smoking and Vaping Surveys (n = 2815). Measurements Plans to quit cigarette smoking was assessed at baseline (within 6 months, beyond 6 months, not planning to quit) and at follow-up (within 6 months vs not within 6 months), cigarette smoking cessation was assessed at follow-up (smoking less than monthly [including complete cessation] vs daily/weekly/monthly smoking) and inter-wave vaping uptake was assesed between baseline and follow-up (none, only non-daily vaping and any daily vaping). Generalized estimating equations were used to evaluate whether inter-wave vaping uptake was associated with smoking cessation at follow-up and with planning to quit at follow-up, each stratified by plans to quit smoking at baseline. Findings Overall, 12.7% of smokers quit smoking. Smokers not initially planning to quit within 6 months experienced higher odds of smoking cessation when they took up daily vaping (32.4%) versus no vaping (6.8%; adjusted odds ratio [AOR], 8.58; 95% CI, 5.06-14.54). Among smokers planning to quit, smoking cessation rates were similar between those who did and did not take up daily vaping (25.1% vs 16.8%; AOR, 1.91; 95% CI, 0.91-4.00), although we could not account for potential use of cessation aids. Daily vaping uptake was associated with planning to quit smoking at follow-up among those initially not planning to quit (AOR,6.32; 95% CI, 4.17-9.59). Conclusions Uptake of nicotine vaping appears to be strongly associated with cigarette smoking cessation among smokers with no initial plans to quit smoking. Excluding smokers not planning to quit from studies on vaping and smoking cessation may underestimate potential benefit of daily vaping for daily smokers.