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Bao W, Xu G, Lu J, Snetselaar LG, Wallace RB. Changes in Electronic Cigarette Use Among Adults in the United States, 2014-2016. JAMA. 2018;319(19):2039–2041. doi:10.1001/jama.2018.4658
Electronic cigarettes (e-cigarettes) are widely marketed as a tool for smoking cessation and a safer alternative to conventional cigarettes. However, the efficacy of e-cigarettes for successful smoking cessation is inconclusive.1,2 Previous studies have reported a rapid increase in the prevalence of e-cigarette use among US adults since 2010.3-5 We analyzed new national survey data to estimate the changes in e-cigarette use among US adults in 2014-2016.
The National Health Interview Survey (NHIS) is a nationally representative annual health survey of the noninstitutionalized, civilian US population. NHIS collects information about health-related topics through in-person household interviews.4 In NHIS 2014-2016, the household response rate ranged from 67.9% to 73.8%. The University of Iowa institutional review board determined that the current study was exempt given the use of deidentified data.
Since 2014, participants 18 years or older were asked about their lifetime use of e-cigarettes:4 “Have you ever used an e-cigarette, even 1 time?” Adults who had ever used an e-cigarette were then asked, “Do you now use e-cigarettes every day, some days, or not at all?” Current use of e-cigarettes was defined as using e-cigarettes every day or some days.4 Participants were also asked about their ever and current use of conventional cigarettes (not including e-cigarettes).
We estimated the prevalence of ever and current e-cigarette use in 2014, 2015, and 2016 overall and by age, sex, race/ethnicity, income, and cigarette smoking, with survey weights to account for unequal probability of selection and nonresponse. P values for differences between years and across population strata were calculated using the F test. Trends in prevalence over the 3 years were tested using a weighted logistic regression model with survey year as a continuous variable. All data analyses were conducted using survey procedures in SAS (SAS Institute), version 9.4. A 2-sided P value less than .05 was considered statistically significant.
This analysis included 101 175 NHIS participants 18 years or older (women, 55.1%; non-Hispanic white, 64.7% ; non-Hispanic black, 12.4% ; Hispanic, 14.7%). The weighted prevalence of ever use of e-cigarettes increased significantly from 2014 to 2016 (12.6% [95% CI, 12.0%-13.2%] in 2014, 13.9% [95% CI, 13.3%-14.5%] in 2015, and 15.3% [95% CI, 14.6%-15.9%] in 2016; P for trend, <.001). Almost all the subgroups evaluated showed a significant increase (Table).
In contrast, the weighted prevalence of current use of e-cigarettes decreased significantly from 2014 to 2016 (3.7% [95% CI, 3.3%-4.1%] in 2014, 3.5% [95% CI, 3.2%-3.7%] in 2015, and 3.2% [95% CI, 2.9%-3.5%] in 2016; P for trend, .02). The decrease was significant in subgroups including individuals 65 years or older, women, non-Hispanic white participants, low-income participants, and current cigarette smokers. However, the prevalence increased significantly among former smokers and never smokers (Table).
In a nationally representative survey among US adults, there was a significant increase in the prevalence of ever use of e-cigarettes between 2014 and 2016. In contrast, the prevalence of current e-cigarette use among US adults declined significantly between 2014 and 2016. These trends may suggest that some individuals are trying but not continuing use of e-cigarettes, but further investigation with individual longitudinal data on use of both e-cigarettes and other nicotine products is needed. Coincident with these findings among adults, the National Youth Tobacco Survey reported that the prevalence of current e-cigarette use among US middle and high school students declined for the first time in 2016, after a continuous increase from 2011 to 2015.6
In this study, current use of e-cigarettes declined among current smokers but increased among former smokers. This pattern may reflect e-cigarette use as adults are transitioning from current to former smokers, but further investigation is warranted. The observed increase in both ever and current e-cigarette use among never smokers is concerning, because these never smokers were being exposed to nicotine and other harmful ingredients.
The main limitation of the study is the relatively short period of observation. Continued surveillance and weighing the long-term risks and benefits of e-cigarette use on public health are warranted.
Accepted for Publication: March 26, 2018.
Corresponding Author: Wei Bao, MD, PhD, Department of Epidemiology, College of Public Health, University of Iowa, 145 N Riverside Dr, CPHB, Room S431, Iowa City, IA 52242 (firstname.lastname@example.org).
Author Contributions: Dr Bao had full access to all of the data in the study and takes responsibility for the integrity of the data and the accuracy of the data analysis. Drs Bao and Xu contributed equally to this work.
Concept and design: Bao, Lu, Wallace.
Acquisition, analysis, or interpretation of data: Bao, Xu, Snetselar.
Drafting of the manuscript: Bao, Xu, Wallace.
Critical revision of the manuscript for important intellectual content: Bao, Lu, Snetselar, Wallace.
Statistical analysis: Bao, Xu, Lu.
Administrative, technical, or material support: Bao, Lu.
Supervision: Bao, Snetselar.
Conflict of Interest Disclosures: All authors have completed and submitted the ICMJE Form for Disclosure of Potential Conflicts of Interest and none were reported.