E-Cigarette Use and Transition in Adult Smoking Frequency: A Longitudinal Study

Introduction: The relationship between e-cigarette use and cigarette smoking is the subject of ongoing debate. There is limited research on e-cigarette use and changes in the frequency of cigarette smoking. This study examines whether the frequency of e-cigarette use is associated with changes in cigarette smoking behavior among U.S. adults. Methods: The study used data (n=20,558) from Waves 1 (2013–2014) and 2 (2014–2015) of the Population Assessment of Tobacco and Health, analyzed in 2019. Multivariable multinomial logistic regression assessed the association between e-cigarette use at Wave 1 and change in cigarette smoking frequency between Waves 1 and 2. Results: Every day cigarette smokers who used e-cigarettes some days (OR=1.95, 95% CI=1.27, 2.98) and every day (OR=3.37, 95% CI=1.78, 6.36) in Wave 1 had significantly higher odds of switching to some days cigarette smoking in Wave 2. Every day smokers who used e-cigarettes every day in Wave 1 had higher odds of becoming former cigarette smokers in Wave 2. Likewise, e-cigarette use at baseline among former cigarette smokers was associated with higher odds of switching to some days cigarette smoking (experimental e-cigarette use: OR=5.43, 95% CI=2.13, 10.72; some days e-cigarette use: OR=4.78, 95% CI=2.13, 10.72). In addition, experimental smokers who were also some days e-cigarettes users in Wave 1 had significantly lower odds of switching to experimental former smokers. Conclusions: Although e-cigarette use may reduce cigarette smoking frequency among continuing smokers, findings suggest that e-cigarette use may be associated with cigarette smoking relapse among former smokers.