Presentation (CTI)

OBJECTIVES: Cigarette smoking is a leading cause of preventable deaths. While multiple actual use studies of electronic nicotine delivery systems (ENDS) have demonstrated reduced cigarette use among smokers after initiation, findings are limited to a period of weeks or months, and longer-term studies are not feasible. In this study, we use target trial emulation to estimate effects of ENDS initiation across 6 years of Population Assessment of Tobacco and Health (PATH) survey data using a novel causal time-zero approach.
METHODS: We extracted data from the PATH study (2013-2019), focusing on adults who were exclusive cigarette smokers in their first survey year. We summarized sociodemographic characteristics and tobacco use behaviors (cigarettes per day [CPD] and initiation of ENDS) across the study period. We used target trial emulation to estimate the relationship between ENDS initiation and cigarette use and quantified the results with linear and logistic regression. These models estimated the effect of ENDS initiation on CPD reduction (continuous reduction and categorical ≥50% reduction), adjusting for age, race, sex, and baseline CPD.
RESULTS: Among 3,388 exclusive cigarette smokers (74% aged 18-34, 78% White, 50% male), 1,142 (34%) initiated ENDS use during the survey period. Participants who initiated ENDS used a similar number of CPD prior to initiation compared to those who did not initiate (13 vs. 15 CPD, p=0.226). CPD reduction was greater for those who initiated ENDS (23% vs. 19%, p< 0.001), and a greater proportion reduced CPD by ≥50% (21% vs. 17%, p=0.002). ENDS initiation was associated with greater reduction in CPD (mean difference: 2.11 [95% CI: 0.06-4.18], p= 0.04) and higher likelihood of achieving ≥50% CPD reduction (aOR: 1.31 [95% CI: 1.10-1.56], p = 0.002).
CONCLUSIONS: Using target trial emulation, we demonstrated a long-term association between ENDS initiation and reduced cigarette use among current smokers in the PATH study.