Association of naturalistic e-cigarette use and smoking cessation in US adults

Temporal imprecision and unaddressed confounding limit inferences whether e-cigarette vaping provides real-world benefits or harms for combustible cigarette smoking cessation. This naturalistic, multilevel longitudinal study of US adults examined whether (semi-)monthly transitions in e-cigarette vaping were associated with attaining smoking abstinence and subsequent post-quit relapse. A nationally representative panel of 1,255 adults who smoked at baseline completed up to 22 bi-weekly and 13 monthly surveys between May 2020 and May 2022. Using multilevel longitudinal models, we assessed within-person transitions in past-7-day vaping status (none, non-daily, daily) as time-lagged, time-varying predictors of 7-day point-prevalence smoking outcomes (0 vs. 1-7 days). Results showed that daily vaping was associated with higher odds of achieving smoking abstinence two weeks later (30.4% vs. 16.3%; adjusted-RR[95%CI]=2.27[1.41-3.69]), while non-daily vaping was not significantly associated (22.5% vs. 16.3%; adjusted-RR[95%CI]=1.05[0.85-1.37]). In 557 instances where participants had achieved at least one month of smoking abstinence, both daily (adjusted-HR[95%CI]=1.31[1.09-1.70]) and non-daily (adjusted-HR[95%CI]=2.82[2.07-4.61]) vaping were linked to increased relapse risk compared to no vaping. These findings suggest that while daily vaping may support short-term smoking cessation, it is associated with a heightened risk of relapse among individuals who have already quit.