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

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.