Association between e-cigarette use initiated after cigarette smoking and smoking abstinence: a cross-sectional study among adolescent established smokers in the USA

Background Recent years have seen a rapid increase in the popularity of electronic cigarettes (e-cigarettes) among adolescents in the USA. Evidence on their role in the continuation of or abstinence from cigarette smoking among young smokers remains scarce. Objective To examine the relationship between e-cigarette use initiated after cigarette smoking and abstinence from cigarette smoking among US adolescent established smokers. Methods The data were drawn from the 2015-2018 National Youth Tobacco Survey-a nationally representative survey of US middle and high school students. Multivariable logistic regression was used to assess the association between ever e-cigarette use and past 30-day abstinence from cigarette smoking. The analytical sample comprised ever established cigarette smokers with or without a history of e-cigarette use after smoking initiation. Results Neither experimental (adjusted OR 0.67, 95% CI 0.39-1.14) nor prior established (adjusted OR 1.56, 95% CI 0.96-2.56) nor current established (adjusted OR 0.65, 95% CI 0.41-1.03) e-cigarette use was statistically significantly associated with subsequent abstinence from cigarette smoking among adolescent ever established smokers. These findings were largely consistent across sensitivity analyses using alternative key definitions, although experimental and current established e-cigarette use was significantly negatively associated with past 6-month abstinence. Conclusions We found no evidence that e-cigarette use among US adolescents already smoking cigarettes is associated with subsequent abstinence from cigarette smoking; there was some evidence of an inverse association among experimental and current established e-cigarette users. These findings could inform future regulatory and public health efforts regarding youth e-cigarette use and the reduction of youth cigarette smoking in the USA.