- Email: [email protected]
Electronic Nicotine Delivery System Use Among U.S. Adults, 2014
Electronic Nicotine Delivery System Use Among U.S. Adults, 2014 Ralph S. Caraballo, PhD, Ahmed Jamal, MBBS, Kimberly H. Nguyen, MS, Nicole M. Kuiper, MPH, René A. Arrazola, MPH Introduction: Electronic nicotine delivery system (ENDS) use has increased rapidly in the U.S. in recent years. The availability and use of ENDS raise new issues for public health practice and tobacco regulation, as it is unknown whether patterns of ENDS use enhance, deter, or have no impact on combustible tobacco product use. This study assessed past-month, lifetime, and frequency of ENDS use among current, former, and never adult cigarette smokers. Methods: Data were analyzed from the 2014 Styles, a national consumer-based probability-based
web panel survey of U.S. adults aged Z18 years (n¼4,269) conducted during June and July. Lifetime ENDS users were defined as those who reported having used ENDS Z1 day in their lifetime. Pastmonth ENDS users were defined as those who reported using ENDS in the past 30 days.
Results: In 2014, overall lifetime and past-month ENDS use was 14.1% and 4.8%, respectively. By smoking status, 49.5% of current, 14.7% of former, and 4.1% of never cigarette smokers had used ENDS in their lifetime, whereas 20.6% of current, 4.0% of former, and 0.8% of never smokers used ENDS in the past month. Among current and former cigarette smokers who ever used ENDS, 44.1% and 44.7% reported using ENDS >10 days in their lifetime, respectively.
Conclusions: Because the effect ENDS use has on combustible tobacco products use is unknown, and lifetime and past-month ENDS use is more common among current than former or never smokers, continued surveillance of ENDS use among adults is critical to programs and policies. (Am J Prev Med 2016;50(2):226–229) Published by Elsevier Inc. on behalf of American Journal of Preventive Medicine
Introduction
E
lectronic nicotine delivery system (ENDS) use— including electronic cigarettes (e-cigarettes), vape pens, e-hookahs, and electronic cigars—has increased rapidly among adults and youth since first being introduced in the U.S. in 2007.1–3 Currently, ENDS are not regulated by the U.S. Food and Drug Administration, although a proposed rule was issued in April 2014 to regulate them under its tobacco product authorities.4 Given that ENDS have only recently entered the U.S. market, significant questions remain regarding ENDS.5–8 According to WHO and the U.S. Surgeon
From the Office on Smoking and Health, National Center for Chronic Disease Prevention and Health Promotion, CDC, Atlanta, Georgia Address correspondence to: Ralph S. Caraballo, PhD, Office on Smoking and Health, National Center for Chronic Disease Prevention and Health Promotion, CDC, 4770 Buford Highway, MS F-79, Atlanta GA 30341. E-mail: [email protected]. 0749-3797/$36.00 http://dx.doi.org/10.1016/j.amepre.2015.09.013
226 Am J Prev Med 2016;50(2):226–229
General, ENDS have the potential for public health benefit or harm.8,9 In the U.S., prevalence of ENDS use among adults is changing rapidly.3 However, little is known about patterns of ENDS use.10 Patterns of ENDS could have important public health implications.11 For example, progression of ENDS use to daily or regular use may have a positive, negative, or no impact on the use of combustible tobacco products. Although most ENDS users are either current or former cigarette smokers,12 little is known about how many days they have used ENDS. This study assessed prevalence and frequency of lifetime and current use of ENDS among current, former, and never adult smokers of cigarettes, using a web-based survey of adults conducted in 2014.
Methods Data Source Styles is a national consumer-based web panel survey of U.S. adults aged Z18 years administered in seasonal waves (Styles is a proprietary database product of Porter Novelli, www.porternovelli.com).
Published by Elsevier Inc. on behalf of American Journal of Preventive Medicine
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Table 1. Adult Prevalence of Past-Month and Lifetime ENDS Use Among Current, Former, and Never Cigarette Smokers,d U.S., 2014 a
b
c
Past-month ENDS use Cigarette smoking status
e
Lifetime ENDS use
n
%
95% CI
%
95% CI
Current smoker
666
20.6
16.6, 24.6
49.5
44.7, 54.2
Former smoker
1,072
4.0
2.7, 5.3
14.7
12.3, 17.2
Never smoker
2,311
0.8
0.2, 1.4
4.1
2.9, 5.3
All
4,049
4.8
4.0, 5.7
14.1
12.8, 15.4
a
Past-month ENDS use was defined as use of these products in the past 30 days. Lifetime ENDS use was defined as having used any ENDS in a lifetime, even 1 day. ENDS use was defined as any use (even 1 day) of any of the following products: electronic or e-cigarettes; electronic hookahs, hookah pens, or vape pens; or some other electronic vapor product, such as e-cigars or e-pipes. d Current cigarette smoking was defined as having smoked a cigarette 1 or more days in the past 30 days; the smoker did not need to have smoked 100 cigarettes in his or her entire life to be defined as a current smoker. Former cigarette smoking was defined as having smoked Z100 cigarettes in a lifetime and not having smoked in the past 30 days. Never cigarette smoking was defined as not having smoked 100 cigarettes in a lifetime and not smoking in the last 30 days. e Sample (n) weighted to the Current Population Survey proportions based on nine factors: gender, age, household income, race/ethnicity, household size, education, Census region, metro status, and prior Internet access. ENDS, electronic nicotine delivery systems. b c
The summer wave of the 2014 Styles was fielded from June 13 through July 7 and was sent to a random sample of 4,545 panelists aged Z18 years. Styles is sampled to be representative of the U.S. population. The panel members were randomly recruited by probability-based sampling (using address-based sampling methods) to reach respondents regardless of whether they had landline phones or Internet access. If needed, households were provided with a laptop computer and Internet access. Adult data were weighted using nine factors: gender, age, household income, race/ ethnicity, household size, education, Census region, metro status, and prior Internet access. The weights were designed to match the U.S. Current Population Survey proportions.13 A total of 4,269 adults aged Z18 years completed the survey, yielding a response rate of 69.0% among eligible participants (N¼6,159). This analysis used de-identified secondary data and was exempt from human subjects review.
electronic hookah (e-hookah), or vape pen in your entire life? Response options were: 1 day, 210 days, 1120 days, 2150 days, 51100 days, and >100 days. Point estimates and 95% CIs were calculated in 2014 using SAS-callable SUDAAN, version 9.2.
Table 2. Adult Prevalence of Past-Montha ENDSb Use Among Current, Former, and Never Cigarette Smokersc Who Reported Lifetimed ENDS Use, 2014 Past-month ENDS use
Measures Lifetime ENDS use was defined as any ENDS use: Have you ever tried any of the following products, even just one time? A list of 13 tobacco products and ENDS products were listed. Three ENDS products listed were grouped by e-cigarettes; e-hookahs, hookah pens, or vape pens; and e-cigars or e-pipes. Past-month ENDS use was defined any ENDS product use in the past 30 days: In the past 30 days, which of the following products (i.e., list of ENDS products) have you used at least once? Current cigarette smoking was defined as having smoked a cigarette in the past 30 days; the smoker did not need to have smoked 100 cigarettes in their entire life to be considered a current smoker. Former smoking was defined as having smoked Z100 cigarettes in a lifetime, but not currently smoking cigarettes every day or on some days. Never smoking was defined as not having smoked 100 cigarettes in a lifetime and not having smoked in the last 30 days. The number of days a participant reported using ENDS was assessed by asking: How many days have you used an electronic vapor product, such as an electronic cigarette (e-cigarette), February 2016
ne
%
95% CI
Current smoker
329
41.7
35.0, 48.4
Former smoker
158
27.0
19.1, 34.9
Never smoker
95
19.6
7.2, 32.1
Cigarette smoking status
a
Past-month ENDS use was defined as use of these products in the past 30 days. ENDS use was defined as any use (even 1 day) of any of the following products: electronic or e-cigarettes; electronic hookahs, hookah pens or vape pens; or some other electronic vapor product such as e-cigars or e-pipes. c Current cigarette smoking was defined as having smoked a cigarette 1 or more days in the past 30 days; the smoker did not need to have smoked 100 cigarettes in his or her entire life to be defined as a current smoker. Former cigarette smoking was defined as having smoked Z100 cigarettes in a lifetime and not having smoked in the past 30 days. Never cigarette smoking was defined as not having smoked 100 cigarettes in a lifetime and not smoking in the last 30 days. d Lifetime ENDS use was defined as having used any of the aforementioned products in a lifetime, even 1 day. e Sample (n) weighted to the Current Population Survey proportions based on nine factors: gender, age, household income, race/ethnicity, household size, education, Census region, metro status, and prior Internet access. ENDS, electronic nicotine delivery systems. b
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Table 3. Number of Days Past-Month and Lifetimeb Users of an ENDSc Used the Product Among U.S. Current, Former, and Never Cigarette Smokers,d 2014 a
Current cigarette smokers e
f
Former cigarette smokers
Never cigarette smokers
Lifetime ENDS
Lifetime ENDSf
n
Lifetime ENDS
Past-month ENDS
1 day
126
18.4 (13.2, 23.7)
—
22.9 (15.2, 30.5)
30.5 (17.7, 43.4)
210 days
167
29.7 (23.6, 35.7)
26.0 (16.8, 35.2)
21.9 (14.3, 29.6)
36.1 (21.8, 50.5)
1120 days
73
16.4 (11.2, 21.5)
19.4 (9.9, 28.9)
8.4 (3.5, 13.3)
—
2150 days
70
15.1 (10.3, 20.0)
17.1 (8.7, 25.5)
9.6 (4.9, 14.4)
—
51100 days
46
6.6 (3.2, 10.0)
10.7 (4.1, 17.3)
10.4 (4.7, 16.2)
—
>100 days
52
6.0 (3.5, 10.2)
14.9 (7.2, 22.5)
16.3 (9.9, 22.8)
—
Missing
50
6.9
—
10.4 (3.6, 17.2)
—
Note: % (95% CI). a Past-month ENDS use was defined as use of these products in the past 30 days. b Lifetime ENDS use was defined as having used any of the ENDS products in a lifetime, even 1 day. c ENDS use was defined as any use (even 1 day) of any of the following products: electronic or e-cigarettes; electronic hookahs, hookah pens or vape pens; or some other electronic vapor product such as e-cigars or e-pipes. d Current cigarette smoking was defined as having smoked a cigarette 1 or more days in the past 30 days; the smoker did not need to have smoked 100 cigarettes in his or her entire life to be defined as a current smoker. Former cigarette smoking was defined as having smoked Z100 cigarettes in a lifetime and not having smoked in the past 30 days. Never cigarette smoking was defined as not having smoked 100 cigarettes in a lifetime and not smoking in the last 30 days. e Sample (n) weighted to CPS proportions based on nine factors: gender, age, household income, race/ethnicity, household size, education, Census region, metro status, and prior Internet access. f Imprecise estimate, so data are suppressed (because sample size is o30, or the relative SE of the estimate is >30%. ENDS, electronic nicotine delivery systems.
Results In 2014, the overall prevalence of past-month and lifetime ENDS use were 4.8% and 14.1%, respectively (Table 1). By smoking status, 20.6% of current, 4.0% of former, and 0.8% of never cigarette smokers used ENDS in the past month, whereas 49.5% of current, 14.7% of former, and 4.1% of never cigarette smokers ever used ENDS in their lifetime (Table 1). Among lifetime ENDS ever users, a total of 41.7%, 27.0%, and 19.6% of current, former, and never smokers reported past-month ENDS use, respectively (Table 2). Among current cigarette smokers who had ever tried ENDS, about 44% used ENDS >10 days, whereas about 62% of past-month ENDS users reported using them >10 days (Table 3). Among former cigarette smokers, 45% used ENDS >10 days in their lifetime. Among current and former smokers who used ENDS in the past 30 days, about 15% and 46% reported use >100 days, respectively.
Discussion Important data are emerging on the prevalence and frequency of ENDS product use by smoking status.10 This study found that about one of two current cigarette smokers ever used ENDS compared with about one of seven former and one of 25 never cigarette smokers.
Also, about one of five current cigarette smokers reported having used an ENDS product in the past 30 days compared with about one in 25 former cigarette smokers. This study did not assess reasons for using ENDS; thus, the authors do not know, for example, if past-month dual cigarette and ENDS users were either substituting some regular cigarettes for ENDS or were they purposely using ENDS as a quit aid. Additionally, this study found, among current and former cigarette smokers who ever used ENDS, that about 44% reported having used ENDS >10 days in a lifetime. Also, 46% of former cigarette smokers who used ENDS in the past 30 days reported having used ENDS for >100 days, the equivalent of using ENDS daily for slightly more than 3 months. It is possible that some former smokers could have successfully used ENDS as a cessation aid.14 It is also possible that some former cigarette smokers who have already quit smoking cigarettes started using ENDS after having quit cigarettes.15
Limitations This study is subject to several limitations. First, it has the inherent limitations of other studies that depend on cross-sectional survey data (e.g., no evidence of a temporal relationship between exposure and outcome). Therefore, longitudinal studies are warranted to understand trajectories and transitions of ENDS and www.ajpmonline.org
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combustible tobacco product use to better understand the potential health net benefit, harm, or no effect of ENDS use. Second, the study did not assess the use of tobacco products other than cigarettes and ENDS. In addition, self-reported information is subject to recall bias. Because this study was conducted using a web panel, it is possible that the sampling may have missed certain demographic groups. Finally, the response rate was 69% and the authors do not know if nonparticipants were different in cigarette smoking or ENDS use than participants.
Conclusions In 2014, lifetime and past-month ENDS use continued to be more prevalent among current than former or never cigarette smokers and almost half of current and former cigarette smokers who ever used ENDS used them for more than 10 days, suggesting a critical need to examine ENDS trajectories and transitions of use. Understanding cigarettes and ENDS use and continued surveillance of ENDS are critical next steps to inform public health policy, planning, and practice. The findings and conclusions in this report are those of authors and do not necessarily represent the official position of CDC. No financial disclosures were reported by the authors of this paper.
References 1. Arrazola RA, Singh T, Corey CG, et al. Tobacco use among middle and high school students—United States, 20112014. MMWR Morb Mortal Wkly Rep. 2015;64(14):381–385. 2. Bunnell RE, Agaku IT, Arrazola RA, et al. Intentions to smoke cigarettes among U.S. middle and high school electronic cigarette users, National Youth Tobacco Surveys, 20112013. Nicotine Tob Res. 2015;17(2):228–235. http://dx.doi.org/10.1093/ntr/ntu166. 3. King BA, Patel R, Nguyen KH, Dube SR. Trends in awareness and use of electronic cigarettes among U.S. adults, 20102013. Nicotine Tob Res. 2015;17(2):219–227. http://dx.doi.org/10.1093/ntr/ntu191.
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4. Food and Drug Administration. Deeming tobacco products to be subject to the Federal Food, Drug, and Cosmetic Act, as amended by the Family Smoking Prevention and Tobacco Control Act; regulations on the sale and distribution of tobacco products and required warning statements for tobacco products; proposed rule. Fed Regist. 2014;79: 23141–23207. 5. Cheng T. Chemical evaluation of electronic cigarettes. Tob Control. 2014;23(Suppl 2):11–17. http://dx.doi.org/10.1136/tobaccocontrol2013-051482. 6. Goniewicz ML, Knysak J, Gawron M, et al. Levels of selected carcinogens and toxicants in vapour from electronic cigarettes. Tob Control. 2014;23(2):133–139. http://dx.doi.org/10.1136/tobaccocontrol-2012-050859. 7. Hecht SS, Carmella SG, Kotandeniya D, et al. Evaluation of toxicant and carcinogen metabolites in the urine of e-cigarette users versus cigarette smokers. Nicotine Tob Res. 2015;7(6):704–709. http://dx.doi. org/10.1093/ntr/ntu218. 8. Abrams DB. Promise and peril of e-cigarettes: can disruptive technology make cigarettes obsolete? JAMA. 2014;311(2):135–136. http://dx. doi.org/10.1001/jama.2013.285347. 9. The health consequences of smoking—50 years of progress: a report of the Surgeon General. Atlanta, GA: U.S. DHHS, CDC, Coordinating Center for Health Promotion, National Center for Chronic Disease Prevention and Health Promotion, Office on Smoking and Health; 2014. www.surgeongeneral.gov/library/reports/50-years-of-progress/ full-report.pdf. Accessed April 30, 2015. 10. Giovenco DP, Lewis MJ, Delnevo CD. Factors associated with e-cigarette use: a national population survey of current and former smokers. Am J Prev Med. 2014;47(4):476–480. http://dx.doi.org/ 10.1016/j.amepre.2014.04.009. 11. Cobb CO, Villanti AC, Graham AL, et al. Markov Modeling to estimate the population impact of emerging tobacco products: a proof-ofconcept Study. Tob Regul Sci. 2015;1(2):129–141. http://dx.doi.org/ 10.18001/TRS.1.2.3. 12. Pepper JK, Brewer NT. Electronic nicotine delivery system (electronic cigarette) awareness, use, reactions and beliefs: a systematic review. Tob Control. 2013;23(5):375–384. http://dx.doi.org/10.1136/tobaccocontrol-2013-051122. 13. Current population survey. U.S. Census Bureau website. 2014. www. census.gov/cps/. Accessed April 30, 2015. 14. Biener L, Hargraves JL. A longitudinal study of electronic cigarette use among a population-based sample of adult smokers: association with smoking cessation and motivation to quit. Nicotine Tob Res. 2015;17 (2):127–133. http://dx.doi.org/10.1093/ntr/ntu200. 15. Choi K, Forster JL. Beliefs and experimentation with electronic cigarettes: a prospective analysis among young adults. Am J Prev Med. 2014;46(2):175–178. http://dx.doi.org/10.1016/j.amepre.2013. 10.007.
web panel survey of U.S. adults aged Z18 years (n¼4,269) conducted during June and July. Lifetime ENDS users were defined as those who reported having used ENDS Z1 day in their lifetime. Pastmonth ENDS users were defined as those who reported using ENDS in the past 30 days.
Results: In 2014, overall lifetime and past-month ENDS use was 14.1% and 4.8%, respectively. By smoking status, 49.5% of current, 14.7% of former, and 4.1% of never cigarette smokers had used ENDS in their lifetime, whereas 20.6% of current, 4.0% of former, and 0.8% of never smokers used ENDS in the past month. Among current and former cigarette smokers who ever used ENDS, 44.1% and 44.7% reported using ENDS >10 days in their lifetime, respectively.
Conclusions: Because the effect ENDS use has on combustible tobacco products use is unknown, and lifetime and past-month ENDS use is more common among current than former or never smokers, continued surveillance of ENDS use among adults is critical to programs and policies. (Am J Prev Med 2016;50(2):226–229) Published by Elsevier Inc. on behalf of American Journal of Preventive Medicine
Introduction
E
lectronic nicotine delivery system (ENDS) use— including electronic cigarettes (e-cigarettes), vape pens, e-hookahs, and electronic cigars—has increased rapidly among adults and youth since first being introduced in the U.S. in 2007.1–3 Currently, ENDS are not regulated by the U.S. Food and Drug Administration, although a proposed rule was issued in April 2014 to regulate them under its tobacco product authorities.4 Given that ENDS have only recently entered the U.S. market, significant questions remain regarding ENDS.5–8 According to WHO and the U.S. Surgeon
From the Office on Smoking and Health, National Center for Chronic Disease Prevention and Health Promotion, CDC, Atlanta, Georgia Address correspondence to: Ralph S. Caraballo, PhD, Office on Smoking and Health, National Center for Chronic Disease Prevention and Health Promotion, CDC, 4770 Buford Highway, MS F-79, Atlanta GA 30341. E-mail: [email protected]. 0749-3797/$36.00 http://dx.doi.org/10.1016/j.amepre.2015.09.013
226 Am J Prev Med 2016;50(2):226–229
General, ENDS have the potential for public health benefit or harm.8,9 In the U.S., prevalence of ENDS use among adults is changing rapidly.3 However, little is known about patterns of ENDS use.10 Patterns of ENDS could have important public health implications.11 For example, progression of ENDS use to daily or regular use may have a positive, negative, or no impact on the use of combustible tobacco products. Although most ENDS users are either current or former cigarette smokers,12 little is known about how many days they have used ENDS. This study assessed prevalence and frequency of lifetime and current use of ENDS among current, former, and never adult smokers of cigarettes, using a web-based survey of adults conducted in 2014.
Methods Data Source Styles is a national consumer-based web panel survey of U.S. adults aged Z18 years administered in seasonal waves (Styles is a proprietary database product of Porter Novelli, www.porternovelli.com).
Published by Elsevier Inc. on behalf of American Journal of Preventive Medicine
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Table 1. Adult Prevalence of Past-Month and Lifetime ENDS Use Among Current, Former, and Never Cigarette Smokers,d U.S., 2014 a
b
c
Past-month ENDS use Cigarette smoking status
e
Lifetime ENDS use
n
%
95% CI
%
95% CI
Current smoker
666
20.6
16.6, 24.6
49.5
44.7, 54.2
Former smoker
1,072
4.0
2.7, 5.3
14.7
12.3, 17.2
Never smoker
2,311
0.8
0.2, 1.4
4.1
2.9, 5.3
All
4,049
4.8
4.0, 5.7
14.1
12.8, 15.4
a
Past-month ENDS use was defined as use of these products in the past 30 days. Lifetime ENDS use was defined as having used any ENDS in a lifetime, even 1 day. ENDS use was defined as any use (even 1 day) of any of the following products: electronic or e-cigarettes; electronic hookahs, hookah pens, or vape pens; or some other electronic vapor product, such as e-cigars or e-pipes. d Current cigarette smoking was defined as having smoked a cigarette 1 or more days in the past 30 days; the smoker did not need to have smoked 100 cigarettes in his or her entire life to be defined as a current smoker. Former cigarette smoking was defined as having smoked Z100 cigarettes in a lifetime and not having smoked in the past 30 days. Never cigarette smoking was defined as not having smoked 100 cigarettes in a lifetime and not smoking in the last 30 days. e Sample (n) weighted to the Current Population Survey proportions based on nine factors: gender, age, household income, race/ethnicity, household size, education, Census region, metro status, and prior Internet access. ENDS, electronic nicotine delivery systems. b c
The summer wave of the 2014 Styles was fielded from June 13 through July 7 and was sent to a random sample of 4,545 panelists aged Z18 years. Styles is sampled to be representative of the U.S. population. The panel members were randomly recruited by probability-based sampling (using address-based sampling methods) to reach respondents regardless of whether they had landline phones or Internet access. If needed, households were provided with a laptop computer and Internet access. Adult data were weighted using nine factors: gender, age, household income, race/ ethnicity, household size, education, Census region, metro status, and prior Internet access. The weights were designed to match the U.S. Current Population Survey proportions.13 A total of 4,269 adults aged Z18 years completed the survey, yielding a response rate of 69.0% among eligible participants (N¼6,159). This analysis used de-identified secondary data and was exempt from human subjects review.
electronic hookah (e-hookah), or vape pen in your entire life? Response options were: 1 day, 210 days, 1120 days, 2150 days, 51100 days, and >100 days. Point estimates and 95% CIs were calculated in 2014 using SAS-callable SUDAAN, version 9.2.
Table 2. Adult Prevalence of Past-Montha ENDSb Use Among Current, Former, and Never Cigarette Smokersc Who Reported Lifetimed ENDS Use, 2014 Past-month ENDS use
Measures Lifetime ENDS use was defined as any ENDS use: Have you ever tried any of the following products, even just one time? A list of 13 tobacco products and ENDS products were listed. Three ENDS products listed were grouped by e-cigarettes; e-hookahs, hookah pens, or vape pens; and e-cigars or e-pipes. Past-month ENDS use was defined any ENDS product use in the past 30 days: In the past 30 days, which of the following products (i.e., list of ENDS products) have you used at least once? Current cigarette smoking was defined as having smoked a cigarette in the past 30 days; the smoker did not need to have smoked 100 cigarettes in their entire life to be considered a current smoker. Former smoking was defined as having smoked Z100 cigarettes in a lifetime, but not currently smoking cigarettes every day or on some days. Never smoking was defined as not having smoked 100 cigarettes in a lifetime and not having smoked in the last 30 days. The number of days a participant reported using ENDS was assessed by asking: How many days have you used an electronic vapor product, such as an electronic cigarette (e-cigarette), February 2016
ne
%
95% CI
Current smoker
329
41.7
35.0, 48.4
Former smoker
158
27.0
19.1, 34.9
Never smoker
95
19.6
7.2, 32.1
Cigarette smoking status
a
Past-month ENDS use was defined as use of these products in the past 30 days. ENDS use was defined as any use (even 1 day) of any of the following products: electronic or e-cigarettes; electronic hookahs, hookah pens or vape pens; or some other electronic vapor product such as e-cigars or e-pipes. c Current cigarette smoking was defined as having smoked a cigarette 1 or more days in the past 30 days; the smoker did not need to have smoked 100 cigarettes in his or her entire life to be defined as a current smoker. Former cigarette smoking was defined as having smoked Z100 cigarettes in a lifetime and not having smoked in the past 30 days. Never cigarette smoking was defined as not having smoked 100 cigarettes in a lifetime and not smoking in the last 30 days. d Lifetime ENDS use was defined as having used any of the aforementioned products in a lifetime, even 1 day. e Sample (n) weighted to the Current Population Survey proportions based on nine factors: gender, age, household income, race/ethnicity, household size, education, Census region, metro status, and prior Internet access. ENDS, electronic nicotine delivery systems. b
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Table 3. Number of Days Past-Month and Lifetimeb Users of an ENDSc Used the Product Among U.S. Current, Former, and Never Cigarette Smokers,d 2014 a
Current cigarette smokers e
f
Former cigarette smokers
Never cigarette smokers
Lifetime ENDS
Lifetime ENDSf
n
Lifetime ENDS
Past-month ENDS
1 day
126
18.4 (13.2, 23.7)
—
22.9 (15.2, 30.5)
30.5 (17.7, 43.4)
210 days
167
29.7 (23.6, 35.7)
26.0 (16.8, 35.2)
21.9 (14.3, 29.6)
36.1 (21.8, 50.5)
1120 days
73
16.4 (11.2, 21.5)
19.4 (9.9, 28.9)
8.4 (3.5, 13.3)
—
2150 days
70
15.1 (10.3, 20.0)
17.1 (8.7, 25.5)
9.6 (4.9, 14.4)
—
51100 days
46
6.6 (3.2, 10.0)
10.7 (4.1, 17.3)
10.4 (4.7, 16.2)
—
>100 days
52
6.0 (3.5, 10.2)
14.9 (7.2, 22.5)
16.3 (9.9, 22.8)
—
Missing
50
6.9
—
10.4 (3.6, 17.2)
—
Note: % (95% CI). a Past-month ENDS use was defined as use of these products in the past 30 days. b Lifetime ENDS use was defined as having used any of the ENDS products in a lifetime, even 1 day. c ENDS use was defined as any use (even 1 day) of any of the following products: electronic or e-cigarettes; electronic hookahs, hookah pens or vape pens; or some other electronic vapor product such as e-cigars or e-pipes. d Current cigarette smoking was defined as having smoked a cigarette 1 or more days in the past 30 days; the smoker did not need to have smoked 100 cigarettes in his or her entire life to be defined as a current smoker. Former cigarette smoking was defined as having smoked Z100 cigarettes in a lifetime and not having smoked in the past 30 days. Never cigarette smoking was defined as not having smoked 100 cigarettes in a lifetime and not smoking in the last 30 days. e Sample (n) weighted to CPS proportions based on nine factors: gender, age, household income, race/ethnicity, household size, education, Census region, metro status, and prior Internet access. f Imprecise estimate, so data are suppressed (because sample size is o30, or the relative SE of the estimate is >30%. ENDS, electronic nicotine delivery systems.
Results In 2014, the overall prevalence of past-month and lifetime ENDS use were 4.8% and 14.1%, respectively (Table 1). By smoking status, 20.6% of current, 4.0% of former, and 0.8% of never cigarette smokers used ENDS in the past month, whereas 49.5% of current, 14.7% of former, and 4.1% of never cigarette smokers ever used ENDS in their lifetime (Table 1). Among lifetime ENDS ever users, a total of 41.7%, 27.0%, and 19.6% of current, former, and never smokers reported past-month ENDS use, respectively (Table 2). Among current cigarette smokers who had ever tried ENDS, about 44% used ENDS >10 days, whereas about 62% of past-month ENDS users reported using them >10 days (Table 3). Among former cigarette smokers, 45% used ENDS >10 days in their lifetime. Among current and former smokers who used ENDS in the past 30 days, about 15% and 46% reported use >100 days, respectively.
Discussion Important data are emerging on the prevalence and frequency of ENDS product use by smoking status.10 This study found that about one of two current cigarette smokers ever used ENDS compared with about one of seven former and one of 25 never cigarette smokers.
Also, about one of five current cigarette smokers reported having used an ENDS product in the past 30 days compared with about one in 25 former cigarette smokers. This study did not assess reasons for using ENDS; thus, the authors do not know, for example, if past-month dual cigarette and ENDS users were either substituting some regular cigarettes for ENDS or were they purposely using ENDS as a quit aid. Additionally, this study found, among current and former cigarette smokers who ever used ENDS, that about 44% reported having used ENDS >10 days in a lifetime. Also, 46% of former cigarette smokers who used ENDS in the past 30 days reported having used ENDS for >100 days, the equivalent of using ENDS daily for slightly more than 3 months. It is possible that some former smokers could have successfully used ENDS as a cessation aid.14 It is also possible that some former cigarette smokers who have already quit smoking cigarettes started using ENDS after having quit cigarettes.15
Limitations This study is subject to several limitations. First, it has the inherent limitations of other studies that depend on cross-sectional survey data (e.g., no evidence of a temporal relationship between exposure and outcome). Therefore, longitudinal studies are warranted to understand trajectories and transitions of ENDS and www.ajpmonline.org
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combustible tobacco product use to better understand the potential health net benefit, harm, or no effect of ENDS use. Second, the study did not assess the use of tobacco products other than cigarettes and ENDS. In addition, self-reported information is subject to recall bias. Because this study was conducted using a web panel, it is possible that the sampling may have missed certain demographic groups. Finally, the response rate was 69% and the authors do not know if nonparticipants were different in cigarette smoking or ENDS use than participants.
Conclusions In 2014, lifetime and past-month ENDS use continued to be more prevalent among current than former or never cigarette smokers and almost half of current and former cigarette smokers who ever used ENDS used them for more than 10 days, suggesting a critical need to examine ENDS trajectories and transitions of use. Understanding cigarettes and ENDS use and continued surveillance of ENDS are critical next steps to inform public health policy, planning, and practice. The findings and conclusions in this report are those of authors and do not necessarily represent the official position of CDC. No financial disclosures were reported by the authors of this paper.
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