Cohort study of electronic cigarette use: safety and effectiveness after 4 years of follow-up

Introduction:
This text reports the results of a four-year follow-up of an observational cohort study evaluating the long-term safety and effectiveness of e-cigarettes. The study included participants who were current or former smokers and used e-cigarettes, either alone or in combination with tobacco cigarettes. The study design and major points are summarized below.

Key Points:

* The study included 915 participants who completed the 48-month follow-up.
* Health outcomes included a rate of possibly smoking-related diseases (PSRD) of 8.0%, with no significant differences between baseline groups.
* After 4 years, 63.6% of the 228 baseline e-cig users were still abstinent from tobacco smoking, while 26.8% of the 471 baseline tobacco smokers and 33.8% of the 216 baseline dual users achieved tobacco abstinence.
* The proportion of subjects who achieved complete abstinence did not significantly differ by baseline group.
* During the follow-up, both baseline dual users and tobacco smokers showed a significant decrease in the mean number of tobacco cigarettes smoked per day.
* A large and significantly higher decrease in the number of tobacco cigarettes smoked per day was observed among dual users when restricted to those who did not switch smoking/vaping status.
* Multivariate analyses were in line with univariate results, with the exception of a significantly lower decrease in self-reported health among e-cig users as compared to tobacco smokers.

Main Message:
The main message of this study is that after four years of follow-up, the use of e-cigarettes, either alone or in combination with tobacco cigarettes, did not significantly decrease the rate of diseases potentially related to tobacco and did not substantially improve self-reported health. However, the complete switch to e-cigarettes did seem to help tobacco quitters to remain abstinent from smoking. The study also highlights the importance of real-life data on the pathways of use of e-cigarette or dual users, as they are limited to two dedicated studies with one year of follow-up. Overall, the study provides valuable information for regulatory matters regarding the safety and effectiveness of e-cigarettes.

Flacco, M E, M Ferrante, M Fiore, C Marzuillo, C La Vecchia, M R Gualano, G Liguori, et al. “Cohort Study of Electronic Cigarette Use: Safety and Effectiveness after 4 Years of Follow-Up,” n.d.