E-cigarettes and Smoking Cessation in the United States According to Frequency of E-cigarette Use and Quitting Duration: Analysis of the 2016 and 2017 National Health Interview Surveys.

The purpose of this study was to examine the association between electronic cigarette (e-cigarette) use and smoking cessation among US adults. Duration of smoking cessation was taken into consideration because e-cigarette awareness and use were low in the United States before 2010. A pooled analysis of the 2016 and 2017 National Health Interview Surveys on current (N = 9935) and former smokers (N = 14 754) was performed. Adjusted prevalence ratios (aPRs), for sociodemographic factors, were calculated. Current e-cigarette use was reported by 10.5% (95% CI = 9.8% to 11.3%) of current smokers and 4.5% (95% CI = 4.0% to 5.0%) of former smokers. Prevalence was high in former smokers of less than 1 year (16.8%, 95% CI = 13.9% to 20.2%), 1-3 years (15.0%, 95% CI = 13.0% to 17.3%), and 4-6 years (10.5%, 95% CI = 8.6% to 12.7%), and very low in former smokers of more than 6 years (0.7%, 95% CI = 0.5% to 0.9%). Similar patterns were observed for daily e-cigarette use. Current e-cigarette use was negatively associated with being a former smoker when quit duration was ignored (aPR = 0.64, 95% CI = 0.59 to 0.69) but was positively associated with being a former smoker of less than 1 year (aPR = 1.44, 95% CI = 1.12 to 1.84) and 1-3 years (aPR = 1.21, 95% CI = 1.03 to 1.42). Daily e-cigarette use was not associated with being a former smoker when quit duration was ignored but was positively associated with being a former smoker of less than 1 year (aPR = 3.44, 95% CI = 2.63 to 4.49), 1-3 years (aPR = 2.51, 95% CI = 2.13 to 2.95), and 4-6 years (aPR = 1.84, 95% CI = 1.49 to 2.26). Daily e-cigarette use is strongly associated with recent smoking cessation (≤6 years) among US adults. Frequency of e-cigarette use and smoking cessation duration are important parameters when analyzing the effects of e-cigarettes in population surveys. There is controversy on whether e-cigarettes promote or prevent smoking cessation. This study presents a detailed analysis of the association between e-cigarette use and smoking cessation in the United States considering frequency of e-cigarette use and duration of smoking cessation. The latter was considered appropriate because e-cigarette awareness and use were low in the United States before 2010. Daily e-cigarette use is strongly associated with recent (≤6 years) smoking cessation in the United States. Both frequency of e-cigarette use and duration of smoking cessation are important factors in determining the effects of e-cigarettes in population studies.

Farsalinos KE ，Niaura R 《-》

Patterns of E-cigarette Use and Subsequent Cigarette Smoking Cessation Over 2 Years (2013/2014-2015/2016) in the Population Assessment of Tobacco and Health Study.

Understanding the population impact of e-cigarettes requires determining their effect on cigarette smoking cessation. Using the US Population Assessment of Tobacco and Health cohort, we examined smoking cessation among adult current cigarette smokers at Wave 1 with follow-up data at Waves 2 and 3 (n = 9724). By Wave 3 (2015/2016), 17.3% of smokers had quit smoking. Smokers using e-cigarettes daily or who increased to daily use over the three waves were two to four times more likely to have quit in the short term (<1 year) and long term (1+ years) compared with never e-cigarette users (p < .001). E-cigarette use in the last quit attempt was associated with a higher likelihood of short-term (<1 year) quitting at Wave 3 (adjusted relative risk ratio: 1.33; 95% confidence interval: 1.04, 1.71) compared with smokers who did not use an e-cigarette in their last quit attempt. Noncurrent (no use in any wave) e-cigarette users and users who were unstable in use frequency were 33% and 47% less likely to quit in the short-term, respectively (p < .001). Flavored (vs nonflavored) and using a rechargeable (vs disposable) e-cigarette device was associated with an increased likelihood of both short- and long-term quitting. Smoking cessation was more likely among frequent e-cigarette users, users of e-cigarettes in last quit attempt, and users of flavored and rechargeable devices. Less frequent, unstable, past, or never e-cigarette users were less likely to quit smoking. Monitoring the relationship between patterns of e-cigarette and cigarette use is complex but critical for gauging the potential of e-cigarettes as a harm reduction tool. This study suggests that consistent and frequent e-cigarette use over time is associated with cigarette smoking cessation among adults in the United States. In addition, findings suggest that flavored e-cigarette use and use of rechargeable e-cigarette devices can facilitate smoking cessation. These results underscore the importance of carefully defining and characterizing e-cigarette exposure patterns, potential confounders, and use of e-cigarettes to quit smoking, as well as variations in length of the smoking cessation.

Glasser AM ，Vojjala M ，Cantrell J ，Levy DT ，Giovenco DP ，Abrams D ，Niaura R ... -  《-》

Prevalence of population smoking cessation by electronic cigarette use status in a national sample of recent smokers.

Amid decreasing rates of cigarette smoking and a rise in e-cigarette use, there is a need to understand population patterns of use to inform tobacco control efforts and evaluate whether e-cigarettes may play a role in tobacco harm reduction. This study merged data from the 2014 and 2015 National Health Interview Survey (NHIS) and restricted the sample to recent smokers [i.e., current smokers and former smokers who quit in 2010 or later (n=15,532)]. Log-binomial regression estimated adjusted prevalence ratios (aPR) for being quit by e-cigarette use status (i.e., daily, some day, former trier, never). All analyses controlled for factors traditionally correlated with smoking cessation. A quarter of the sample (25.2%) were former smokers. The prevalence of being quit was significantly higher among daily e-cigarette users compared to those who had never used e-cigarettes [52.2% vs. 28.2%, aPR: 3.15 (2.66, 3.73)]. Those who used e-cigarettes on some days were least likely to be former smokers (12.1%). These relationships held even after accounting for making a quit attempt and use of other tobacco products. Among those with a recent history of smoking, daily e-cigarette use was the strongest correlate of being quit at the time of the survey, suggesting that some smokers may have quit with frequent e-cigarette use or are using the products regularly to prevent smoking relapse. However, the low prevalence of cessation among infrequent e-cigarette users highlights the need to better understand this subgroup, including the individual factors and/or product characteristics that may inhibit cessation.

Giovenco DP ，Delnevo CD 《-》

Use of E-Cigarettes Among Current Smokers: Associations Among Reasons for Use, Quit Intentions, and Current Tobacco Use.

Research has documented growing availability and use of e-cigarettes in the United States over the last decade. We conducted a national panel survey of current adult cigarette smokers to assess attitudes, beliefs, and behaviors relating to e-cigarette use in the United States (N = 2,254). Among current cigarette smokers, 20.4% reported current use of e-cigarettes on some days and 3.7% reported daily use. Reported reasons for e-cigarette use included: quit smoking (58.4%), reduce smoking (57.9%), and reduce health risks (51.9%). No significant differences in sociodemographic characteristics between e-cigarette users and nonusers were observed. Prior quit attempts were reported more frequently among e-cigarette users (82.8%) than nonusers (74.0%). Intention to quit was reported more frequently among e-cigarette users (64.7%) than nonusers (46.8%). Smokers intending to quit were more likely to be e-cigarette users than those not intending to quit (odds ratio [OR] = 1.90, CI =1.36-2.65). Those who used e-cigarettes to try to quit smoking (OR = 2.25, CI = 1.25-4.05), reduce stress (OR = 3.66, CI = 1.11-12.09), or because they cost less (OR = 3.42, CI = 1.64-7.13) were more likely to report decreases in cigarette smoking than those who did not indicate these reasons. Smokers who reported using e-cigarettes to quit smoking (OR = 16.25, CI = 8.32-31.74) or reduce stress (OR = 4.30, CI = 1.32-14.09) were significantly more likely to report an intention to quit than those who did not indicate those reasons for using e-cigarettes. Nearly a quarter of smokers in our study reported e-cigarettes use, primarily motivated by intentions to quit or reduce smoking. These findings identify a clinical and public health opportunity to re-engage smokers in cessation efforts.

Rutten LJ ，Blake KD ，Agunwamba AA ，Grana RA ，Wilson PM ，Ebbert JO ，Okamoto J ，Leischow SJ ... -  《-》

Current and Former Smokers' Use of Electronic Cigarettes for Quitting Smoking: An Exploratory Study of Adolescents and Young Adults.

This exploratory study examines the prevalence and predictors of current and former smokers' use of electronic (e-) cigarettes for smoking cessation among a sample of adolescent and young adult established smokers. We conducted school-wide surveys in two middle (n = 1166) and four high schools (n = 3614) in fall 2013 and one public college (n = 625) in spring 2014. We analyzed data from 189 established smokers (reported smoking 100 cigarettes in their lifetime) who also reported ever-use of e-cigarettes (50.7% female, 89.4% White race, Mage 18.3 [SD = 2.8]). We further classified participants as current smokers (reported past-month cigarette smoking) and former smokers (no past-month smoking). Adjusted logistic regression assessed associations of using e-cigarettes to quit smoking with demographic, cigarette and e-cigarette use patterns, e-cigarette flavor preference, and risk perception variables. Overall, 41.8% of the sample reported that they "have used an e-cigarette to quit smoking." In adjusted models, older age, White race, higher e-cigarette frequency, and preference for using a combination of e-cigarette flavors predicted increased odds of having used e-cigarettes to quit smoking (p < .05). Using e-cigarettes to quit smoking was not associated with current or former cigarette smoking status or perceptions that "e-cigarettes help people quit smoking" or "e-cigarettes are safer than quit smoking medications." Adolescents and young adults who report more frequent e-cigarette use and preference for using flavor combinations are more likely to use e-cigarettes for smoking cessation. Future studies are needed to determine whether e-cigarette use leads to tobacco abstinence in youth smokers. Among young established smokers, more frequent e-cigarette use and preference for using flavors mixed together, but not perceptions of harmfulness of e-cigarettes or comparative safety of e-cigarettes compared with cigarettes or other smoking cessation medications or helpfulness of e-cigarettes in quitting smoking, are associated with using e-cigarettes for smoking cessation.

Camenga DR ，Kong G ，Cavallo DA ，Krishnan-Sarin S ... -  《-》