Cohort study of electronic cigarette use: effectiveness and safety at 24 months

Abstract

ObjectiveTo evaluate the safety and effectiveness of e-cigarettes, by comparing users of only e-cigarettes, smokers of only tobacco cigarettes and dual users.DesignProspective cohort study. We update previous 12-month findings and report the results of the 24-month follow-up.Data sourcesDirect contact and questionnaires by phone or via internet.MethodsAdults (30–75 years) were classified as: (1) tobacco smokers, if they smoked ≥1 tobacco cigarette/day, (2) e-cigarette users, if they inhaled ≥50 puffs/week of any type of e-cigarette and (3) dual users, if they smoked tobacco cigarettes and also used e-cigarettes. Carbon monoxide levels were tested in 50% of those declaring tobacco smoking abstinence. Hospital discharge data were used to validate possibly related serious adverse events in 46.0% of the sample.Main outcome measuresSustained abstinence from tobacco cigarettes and/or e-cigarettes after 24 months, the difference in the number of tobacco cigarettes smoked daily between baseline and 24 months, possibly related serious adverse events.ResultsData at 24 months were available for 229 e-cigarette users, 480 tobacco smokers and 223 dual users (overall response rate 68.8%). Of the e-cigarette users, 61.1% remained abstinent from tobacco (while 23.1% and 26.0% of tobacco-only smokers and dual users achieved tobacco abstinence). The rate (18.8%) of stopping use of either product (tobacco and/or e-cigarettes) was not higher for e-cigarette users compared with tobacco smokers or dual users. Self-rated health and adverse events were similar between all groups. Among those continuing to smoke, there were no differences in the proportion of participants reducing tobacco cigarette consumption by 50% or more, the average daily number of cigarettes and the average self-rated health by baseline group. Most dual users at baseline abandoned e-cigarettes and continued to smoke tobacco. Those who continued dual using or converted from tobacco smoking to dual use during follow-up experienced significant improvements in the 3 outcomes compared with those who continued or switched to only smoking tobacco (p<0.001).ConclusionsE-cigarette use alone might support tobacco quitters remaining abstinent from smoking. However, dual use did not improve the likelihood of quitting tobacco or e-cigarette use, but may be helpful to reduce tobacco consumption. Adverse event data were scarce and must be considered preliminary.Trial registration numberNCT01785537.

What factors are associated with current smokers using or stopping e-cigarette use?

“…To note, dependence was measured using the Heaviness of Smoking index, which might be lower among dual users who tend to reduce the number of cigarettes (Brose et al, 2015, Manzoli et al, 2016, McRobbie et al, 2014). The main reasons for discontinuation suggest that more dependent smokers may find vaping not sufficient, thus increasing their risk of stopping use but continuing to smoke.…”

“…Regardless of medicinal licensing, it is agreed that continuing to smoke is more harmful to health than switching to e-cigarettes (Grana et al, 2014, McNeill et al, 2015; Royal College of Physicians, 2016). Therefore, the two thirds of smokers who try but later stop using e-cigarettes while continuing to smoke (ASH, 2016a, Manzoli et al, 2016, Pepper et al, 2014) constitute a missed opportunity for harm reduction or smoking cessation.…”

Cardiovascular effects of electronic cigarettes

“…Longitudinal and survey studies have assessed adverse events and measures of physical health among EC users, but few reports of cardiovascular events exist 100,101 . A case report described a patient aged 70 years with multiple medical issues who developed episodes of paroxysmal atrial fibrillation that were preceded by EC use 102 .…”

A Naturalistic, Randomized Pilot Trial of E-Cigarettes: Uptake, Exposure, and Behavioral Effects

“…Most studies that assess the impact of ENDS on smoking are either cross-sectional or observational cohort designs (3,4). Evidence suggests that the majority of ENDS users have intention to reduce and/or quit smoking (5), and a range of studies have shown ENDS use to be associated with quit attempts (6), reduction and/or cessation (7-16). More recent cohort studies further document a positive association between use and subsequent quitting (17,18), particularly when ENDS are used regularly (19-21).…”