Does e-liquid flavoring help adult smokers switch from cigarettes to electronic cigarettes?

E-cigarette use has grown dramatically in recent years in the US.1 About 4.4% of adults aged 18 and over currently used e-cigarette in 2019 in the US.2 About 20.8% of adolescents in grades 9–12 used e-cigarette in the past 30 days in 2019 in the US.2 While adolescent use prevention is a concern and an important goal, research is ongoing to determine if e-cigarette can support switching, facilitate quitting, and potential harm reduction among adult combustible cigarette smokers.3,4 E-cigarettes are the most popular assisted method of quitting among adult smokers in the US (although not FDA approved for cessation), with nearly half of adult smokers choosing this method in their most recent quit attempt.5 Within the tobacco control world there is debate if e-cigarettes are an appropriate harm reduction method or not.6 To date, the FDA has not approved e-cigarettes as cessation devices. The National Academies of Science, Engineering, and Medicine 2018 report concluded that, when used exclusively, e-cigarettes pose significantly less exposure to toxicants and less short-term health risks than combustible cigarettes.7,8 Two recent and comprehensive reviews support e-cigarettes as a smoking cessation aid when used as part of an intervention.6,9 According to a 2017 study, between 1.6–6.6 million lives could be saved over a 10-year period in the US by switching cigarette smokers to e-cigarette use.10 There is a continuum of risk from smoking cigarettes to not smoking at all.11 E-cigarette…