LAUSR

BACKGROUND AND AIM Electronic nicotine delivery systems (ENDS) can help people quit smoking combusted tobacco products (CTP), but most current and former smokers who use ENDS also intend to quit ENDS. This analysis measured whether ENDS cessation among current and former CTP smokers is associated with changes in CTP smoking or abstinence. DESIGN Regression analysis of a nationally representative cohort from Waves 4 (W4) and 5 (W5) of the Population Assessment of Tobacco and Health Study (December 2016-November 2019). SETTING USA PARTICIPANTS: Adults (N=1,525) who reported W4 current or former use of ≥1 CTP and either currently using ENDS or quitting ENDS in the past year were included. MEASUREMENTS Logistic regressions were performed separately among W4 current and former CTP smokers, controlling for demographic and tobacco use characteristics. First, we analyzed proximal outcomes by testing the association between ENDS quit status and CTP abstinence, both occurring during W5. Next, we analyzed long-term outcomes by testing W4 ENDS quit status as a predictor of CTP abstinence at W5, approximately 1 year later. FINDINGS Among W4 current CTP smokers, there was no evidence that CTP smoking abstinence differed between those quitting or continuing using ENDS, both in our proximal (adjusted odds ratio [aOR]=1.37, 95% confidence interval [CI]=0.90, 2.10) and long-term (aOR=0.90, 95% CI=0.52, 1.53) analyses. Among former CTP smokers, quitting ENDS was associated with less CTP abstinence in our proximal analysis (aOR=0.42, 95% CI=0.20, 0.89) but there was no evidence that CTP smoking abstinence differed between those quitting or continuing using ENDS in our long-term analysis (aOR=0.86, 95% CI=0.44, 1.67). CONCLUSIONS There is no evidence that electronic nicotine delivery systems (ENDS) cessation is associated with combusted tobacco product abstinence among current smokers, although mixed findings among former smokers indicate a possible risk for relapse to smoking associated with quitting ENDS.