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

INTRODUCTION: 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.
METHODS: 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.
RESULTS: 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.
CONCLUSIONS: 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.