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The Use and Perception of Electronic Cigarettes and Snus among the U.S. Population

The Use and Perception of Electronic Cigarettes and Snus among the U.S. Population Background: E-cigarettes have generated controversy in the tobacco control field similar to that of Swedish snus, which came to the U.S. market six years earlier. Some argue that e-cigarettes have great potential to help smokers quit regular cigarettes while others contend they should be banned for lack of safety and efficacy data. This study examined population data from the U.S. Methods: A U.S. population survey with a national probability sample (N=10,041) was conducted (February 24 to March 8, 2012, before any major paid advertisement of e-cigarettes appeared on television). Survey respondents were asked if they had heard about e-cigarettes, where they had heard about them, whether they had used e- cigarettes or snus, how often they used them, and why they used them. Responses were weighted to represent the entire U.S. population. Findings: A high proportion, 75.4%, reported having heard about e-cigarettes. Television ranked as the number one source of information, followed by “in-person conversation” and “Internet.” About 8.1% had tried e-cigarettes, and 1.4% were current users. These rates were twice those of snus (4.3% and 0.8%, respectively). Among current smokers, 32.2% had tried e-cigarettes, and 6.3% were current users. Over 80% of current e-cigarette users were non-daily users. Women were significantly more likely to have tried e-cigarettes than men. Those who had tried e- cigarettes were more likely than those who tried snus to report their products being safer than regular cigarettes (49.9% vs. 10.8%). Almost half (49.5%) of current smokers were susceptible to using e-cigarettes in the future. Conclusions: That e-cigarettes have surpassed snus in adoption rate, even before any promotion by major tobacco companies, suggests that the former have tapped into smokers’ intuitive preference for potentially harm-reducing products, probably due to the product design. E-cigarette use is likely to increase in the next few years. Citation: Zhu S-H, Gamst A, Lee M, Cummins S, Yin L, et al. (2013) The Use and Perception of Electronic Cigarettes and Snus among the U.S. Population . PLoS ONE 8(10): e79332. doi:10.1371/journal.pone.0079332 Editor: Alan Blum, University of Alabama, United States of America Received July 16, 2012; Accepted October 1, 2013; Published October 24, 2013 Copyright: © 2013 Zhu et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. Funding: This work was supported by a grant from the National Cancer Institute (http://www.cancer.gov), U01 CA154280. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript. Competing interests: The authors have declared that no competing interests exist. * E-mail: [email protected] Introduction help them quit smoking abound [3,7,12-14], but efficacy data in the form of clinical trials are still limited [15-19]. The Electronic Nicotine Delivery System (ENDS), also known Insufficient scientific research on the safety and efficacy of e- as the e-cigarette, has increasingly attracted the attention of cigarettes is one reason that the products have attracted smokers and tobacco control workers [1,2]. E-cigarettes were controversy. Some countries have banned the sale of e- first developed in China in 2003 [3]. They came to the U.S. cigarettes [20], although that does not prevent smokers from market in 2007 and quickly gained notoriety in many countries, purchasing them on the Internet. In the U.S., the Food and especially those with relatively strong tobacco control programs Drug Administration (FDA) has attempted to regulate the sale [4-9]. Unfortunately, scientific information about e-cigarettes is and marketing of e-cigarettes, a move that was struck down by limited. Some argue that e-cigarettes are obviously less a federal court [21]. Short of FDA regulatory oversight, some harmful than cigarettes and have great potential to help states have tried to pass laws to ban the sale of e-cigarettes in smokers quit [10,11], while others contend that data on safety their own jurisdictions [22] although the availability of e- are needed before e-cigarettes are promoted or allowed to be cigarettes on the Internet makes it difficult to enforce such a sold [1]. Anecdotal reports of smokers using e-cigarettes to ban. Meanwhile, the rationale for the ban itself appears to be PLOS ONE | www.plosone.org 1 October 2013 | Volume 8 | Issue 10 | e79332 Use and Perception of E-Cigarettes and Snus chiefly based on predicted potential harm, as empirical Methods evidence is sparse [11]. This controversy surrounding e-cigarettes is reminiscent of Ethics Statement the controversy associated with another tobacco product, snus. This research was performed in accordance with a human Snus, a moist smokeless tobacco product popular in Sweden, subjects protocol approved by the University of California, San gained the attention of global tobacco control workers a few Diego’s Institutional Review Board (IRB# 111664). years before e-cigarettes did [23]. Strong arguments for and Data source against snus have been advanced, but the tobacco control field remains divided [24-27]. Especially difficult is the debate on the The data for this study was obtained from a survey potential of snus to reduce the harm of tobacco use at the commissioned by the University of California, San Diego and administered by Knowledge Networks (Menlo Park, CA). population level [27]. While using snus may be less risky than Knowledge Networks, which was recently acquired by GfK, smoking cigarettes to the health of the individual, it is not clear recruits a probability sample representative of the U.S. that promoting the use of snus would reduce the total harm population (KnowledgePanel). The sample was originally associated with tobacco use at the population level [28,29]. recruited by random digit dialing (RDD) but an address-based Some have argued that promoting the use of any tobacco sampling methodology has been used in recent years [38]. A product supports the tobacco-use norm and, as such, would detailed description of the sampling methods used to recruit to produce a negative net-effect on tobacco control at the the KnowledgePanel has been described elsewhere [39]. The population level [27]. Similar difficulty exists in the current advantages and the limitations of using the KnowledgePanel controversy on e-cigarettes. have also been discussed in many contexts and will not be There is, however, one noticeable difference in the short repeated here [40-42]. In summary, the panel provides an history of e-cigarettes and snus in the U.S. market. E-cigarettes efficient way of accessing a probability sample of the U.S. seem to have achieved notoriety relatively quickly without population, whose representativeness is similar to most other major paid advertising [30]. Unlike snus, which has been well-known population surveys [42-46]. All Knowledge promoted by large tobacco companies in the U.S. [31,32], e- Networks surveys are performed online. Knowledge Networks provides a netbook computer and network access to cigarettes had not been promoted by any major tobacco participants, as needed. Many health behavior studies have company until Lorillard Inc. acquired a major brand Blu-Cigs in used the KnowledgePanel [45,47,48]. April 2012 [33]. Instead, e-cigarettes appear to have received The present survey was designed to gather information on much free publicity. No study has carefully documented the smoking history and cigarette use, perceptions about different level of paid advertising versus earned media for e-cigarettes. tobacco products and quitting aids, attitudes toward tobacco But a quick web search will show that e-cigarettes have control efforts, and beliefs and ideation about the process of received much free coverage. For example, endorsements quitting smoking. The study over sampled the smokers in the have come from some American celebrities and talk show KnowledgePanel so that all the available smokers were hosts, who tout e-cigarettes’ intuitive appeal and how they can included, with a random sub-sample of former smokers and help smokers quit cigarettes [34,35]. E-cigarettes have never smokers from the panel such that the three smoking- appeared in popular movies [35,36]. By 2010, web searches for status groups were approximately equal in size. A total of information on e-cigarettes in that year had surpassed those for 15,095 adults (> 18 years of age) were sampled and invited to snus in the U.S. [6] All this suggests that the adoption of e- participate in the survey. Of these, 10,041 completed the cigarettes may be significant, and a comparison with the survey, a response rate of 66.5%. This corresponds to a sample with 3,111 current smokers, 3,676 former smokers and adoption of snus will be informative. 3,254 never smokers. The survey was conducted between The present study aimed to provide some basic measures on th th February 24 and March 8 , 2012. how much of a foot-hold e-cigarettes had already taken among the U.S. population before Lorillard Inc. purchased a well- Measurement known e-cigarette brand and started a significant television Cigarette smoking behavior was assessed in multiple advertising campaign [33,37]. Using a survey of a probability questions. Current smokers were defined as those who had sample of the U.S. population, this study examined the smoked at least 100 cigarettes in their lifetime and who knowledge about e-cigarettes among smokers and answered the question, “Do you currently smoke cigarettes nonsmokers. It provided population prevalence measures on every day, some days, or not at all?” with “every day” or “some ever and current use of e-cigarettes and the rate of transition days”. Those who had smoked at least 100 cigarettes in their from ever use to current use. The perceived utility of e- lifetime and answered “not at all” were classified as former cigarettes as a quitting aid or as a potential harm reduction smokers. Former smokers were further asked, “When did you product was assessed and compared with that of snus, a smoke your last cigarette?” They were categorized as recent potential harm reduction product that aroused similar former smokers if they selected any of the options with a time controversy when it came to the U.S. a few years before e- frame of 1 year or less, and long-term former smokers if they cigarettes. Finally, the proportion of the U.S. population that is answered “Over 1 year ago”. Nonsmokers were defined as susceptible to future e-cigarettes was estimated. those who had not smoked 100 cigarettes in their lifetime. PLOS ONE | www.plosone.org 2 October 2013 | Volume 8 | Issue 10 | e79332 Use and Perception of E-Cigarettes and Snus Current smokers were asked if they had ever tried to quit survey-specific sampling design. In this case, this survey had smoking, and if they answered yes, were also asked whether approximately equal numbers of current smokers, former they had tried to quit in the last 12 months. smokers, and never smokers. The adjustment for over- Use of snus was assessed by the question, “Have you ever sampling of smokers produced an overall smoking prevalence used any of the following tobacco products?” for which “Snus for the U.S. of 19.1% based on this survey, which is quite close (tobacco in a small pouch, like Camel snus or Marlboro snus)” to the newest published national estimate of 19.3% based on was one of the available options. Those who selected “yes” the 2010 National Health Interview Survey [50]. All results were were defined as ever users of snus and asked the question “Do analyzed by demographic categories (gender, age, educational you currently use snus every day, some days, or not at all?” level, ethnic background), as well as by smoking status. Those selected “every day” or “some days” were defined as Standard errors were calculated and 95% confidence intervals current users of snus. were computed based on the sampling distribution of the Use of e-cigarettes was also assessed in multiple questions. corresponding summary statistic. Confidence intervals for First, respondents were asked if they have ever heard of e- binomial proportions were computed using the method of cigarettes: “E-cigarettes (electronic cigarettes) are electronic Agresti and Coull ([51]; see also 52). All calculations were done devices that deliver nicotine in a vapor and look like cigarettes, using R 2.12.1 [53]. but contain no tobacco. Have you ever heard of e-cigarettes?” Those who had heard of e-cigarettes were also asked where Results they had heard about e-cigarettes and were allowed to select one or more of the following options: “Radio”, “TV”, “Internet”, Figure 1 shows the rate of having “ever used” and “currently “In-person conversation”, “Information shared via Facebook, use” for e-cigarettes and snus, weighted to the U.S. population. YouTube, or other social network media”, and “Other”. A total of 8.08% reported that they had ever used e-cigarettes, Additionally, those who had heard of e-cigarettes were and 1.44% reported currently using e-cigarettes. Thus, asked: “Have you ever tried an e-cigarette”, and those who approximately 18% of those who have ever used e-cigarettes answered yes were considered ever users. Ever users were continue as current users (1.44/8.08 =17.8%). also asked “Have you used e-cigarettes in the last 30 days”, The rate of ever used and current use for snus is and those who answered yes were considered current users. approximately half that of e-cigarettes: 4.26% and 0.77%, Current users were asked to provide the number of days (in the respectively. The rate of transition from ever users of snus to last 30) they had used e-cigarettes. current users, however, is about the same, 18% (0.77/4.26 = Ever users of e-cigarettes were asked “Why did you use e- 18.1%). cigarettes?” and instructed to select “Yes” or “No” for each of Table 1 presents the usage rates of e-cigarettes and snus by the following options: “Safer than cigarettes”, “Cheaper than demographic categories. It also separates out those who used cigarettes,” “Easy to use when I can’t smoke,” “To try to quit only e-cigarettes or snus from those who used both products. smoking cigarettes”, or “Just because.” Since a person could The top half of the table shows the “ever use” rates. Women have multiple reasons for using any product, the order of these are more likely to have ever used e-cigarettes than men. The options was randomized by individual respondent to minimize usage rate is higher among the young and those with lower the order effect in response (e.g., respondent may be more education. Hispanics are less likely to have ever used e- likely to choose the first option on the list). The “just because” cigarettes than either Whites or Blacks. option was included to make clear that the respondent need The usage rates for snus are significantly lower. The main not have any particular reason. difference is in gender: About the same percentage of men Finally, those who had never used e-cigarettes were asked have tried e-cigarettes or snus: 7.17 % (5.33% + 1.84%) for e- the question: “How likely are you to try e-cigarettes in the cigarettes and 7.10% (5.26% + 1.84%) for snus. However, the future?” This was intended to assess their susceptibility to e- percentage of women having tried e-cigarettes is much higher cigarettes, much like the susceptibility measure on uptake of than for snus 8.92% (8.33% + 0.59%) versus 1.65% (1.06% + regular cigarettes [49]. Those who responded that they were 0.59%). “Very likely” or “Somewhat likely” were considered to be The bottom half of Table 1 shows the rates of current use. susceptible. This is slightly stricter definition than the The demographic pattern for the “currently use” is similar to susceptibility measure used in the literature for uptake of that for “ever used” except that the rates for the former are cigarettes in that the present definition does not include those significantly lower across all demographic categories. who responded “somewhat unlikely” [49]. The susceptibility Table 2 shows the rates of ever used and current use by definition here does include those who have tried e-cigarettes smoking status and by gender. In this table, all users of e- but are not currently using them. cigarettes are combined into one group regardless of whether they use snus or not. The same is done for snus users: They Analysis are combined into one group of snus users regardless of their All percentages were weighted by population parameters e-cigarette use status (thus, dual users are counted in both calculations). based on the most recent U.S. Current Population Survey [46]. A survey-specific post-stratification adjustment was used to Table 2 shows that the difference in usage rates by smoking account for any survey non-response, as well as any non- status is large. About 1% of never smokers have ever tried e- coverage or under- and over-sampling resulting from the cigarettes, while over 32% of current smokers have used e- PLOS ONE | www.plosone.org 3 October 2013 | Volume 8 | Issue 10 | e79332 Use and Perception of E-Cigarettes and Snus Figure 1. The rates of ever use and current use of E-Cigarettes and Snus. doi: 10.1371/journal.pone.0079332.g001 cigarettes. The same is true with ever using snus. Clearly, Most snus users used snus on a non-daily basis. Among the long-term former smokers, however, most used snus on a daily recent former smokers and current smokers are the most likely basis. to have tried e-cigarette or snus. Table 4 shows the reasons of use, reported by the ever e- There is also a significant gender difference in ever using e- cigarette users and ever snus users. It is useful to take a look cigarettes or snus. This gender difference is most clearly seen at those who used both products, first (the last two columns of among the current smokers: women are more likely to have the table). The most common reason for having tried e- tried e-cigarettes than men (about 38% vs. 27%). In contrast, cigarettes or snus is “just because:” 72.3% for e-cigarettes and men are more likely to have tried snus (about 17% vs. 6%). It 82.1% for snus. For e-cigarettes, the second most common should be noted, however, that both women and men are more reason given is “to try to quit smoking cigarettes,” followed by likely to have tried e-cigarettes than snus. “safer than cigarettes” and “easy to use when I can’t smoke.” Table 2 also shows that the current use rates have a similar For snus, the second most common reason is “easy to use pattern to the ever use rates. It is recent former smokers and when I can’t smoke,” “followed by to try to quit smoking current smokers who are more likely to be current users of e- cigarettes.” Overall, the dual users are significantly more likely cigarettes or snus. The gender difference between e-cigarette to report use of e-cigarettes than snus to quit smoking, 56.9% vs. 30.1%. Dual users are more likely to report the belief that e- and snus use is reversed in this comparison, but the difference cigarettes are safer than cigarettes, 58.2% vs. 26.2% for snus. is not statistically significant. The overall rates, however, are The patterns for those using either e-cigarettes only or snus significantly higher for e-cigarettes than for snus among recent only are presented in columns 1 and 2, and they are similar to formers smokers and current smokers. that of dual users. E-cigarette users are about twice as likely as Table 3 shows the frequency of use for e-cigarettes or snus snus users to report using the product “to try to quit smoking” among those who currently use either of these two types of (54.9% vs. 26.3%). The former are also significantly more likely products. Among e-cigarette users, there is a significant to believe e-cigarettes are safer than regular cigarettes than difference in the use pattern between current smokers and the latter are to believe snus is safer than cigarettes (49.9% vs. recent former smokers. Among current smokers, those who 10.8%). used e-cigarettes were mostly occasional users, only 11.5% of Figure 2 shows that those who are currently using e- used e-cigarettes daily. Among recent former smokers, cigarettes are significantly more likely to have tried to quit however, 45.7% used them on a daily basis, a statistically smoking in the last 12 months than those who are currently not significant difference (p<0.05). using e-cigarettes. The former are also more likely to have PLOS ONE | www.plosone.org 4 October 2013 | Volume 8 | Issue 10 | e79332 Use and Perception of E-Cigarettes and Snus Table 1. Ever and Current Use of E-Cigarettes and Snus (n = 10,041). Ever Use E-cigarettes only Snus only E-Cigarettes and Snus % (95% CI) % (95% CI) % (95% CI) Mean 6.89 (6.40-7.39) 3.07 (2.73-3.41) 1.19 (0.98-1.40) Gender Male 5.33 (4.51-6.15) 5.26 (4.32-6.20) 1.84 (1.25-2.43) Female 8.33 (7.33-9.33) 1.06 (0.63-1.49) 0.59 (0.28-0.90) Age 18-24 9.33 (6.59-12.07) 3.54 (1.60-5.48) 3.37 (1.49-5.25) 25-44 7.78 (6.43-9.13) 3.98 (2.92-5.04) 1.69 (1.02-2.36) 45-54 7.35 (6.47-8.23) 2.88 (2.23-3.53) 0.52 (0.28-0.76) 65+ 2.62 (19.3-3.31) 1.25 (0.78-1.72) 0.34 (0.00-0.69) Education ≤12 years 8.60 (7.37-9.83) 3.48 (2.60-4.36) 1.61 (1.23-1.99) >12 years 5.63 (4.94-6.32) 2.76 (2.17-3.35) 0.88 (0.61-1.15) Ethnicity Non-Hispanic White 7.02 (6.29-7.75) 3.27 (2.66-3.88) 1.32 (0.91-1.73) Black 8.12 (5.55-10.69) 1.19 (0.39-1.99) 0.35 (0.00-0.74) Hispanic 4.38 (1.81-6.95) 4.40 (1.64-7.16) 1.42 (0.00-3.07) Other 6.14 (4.87-7.40) 2.94 (1.43-4.45) 1.22 (0.64-1.80) Multi-racial 9.51 (5.24-13.78) 4.69 (0.97-8.41) 0.52 (0.00-1.07) Current Use E-cigarettes only Snus only E-Cigarettes and Snus % (95% CI) % (95% CI) % (95% CI) Mean 1.28 (1.06-1.50) 0.61 (0.46-0.76) 0.16 (0.08-0.24) Gender Male 1.00 (0.65-1.35) 0.96 (0.53-1.39) 0.22 (0.00-0.46) Female 1.54 (1.13-1.95) 0.29 (0.11-0.47) 0.10 (0.00-0.26) Age 18-24 1.47 (0.33-2.61) 0.27 (0.00-0.58) 0.23 (0.00-0.48) 25-44 1.19 (0.62-1.76) 0.75 (0.28-1.22) 0.29 (0.00-0.62) 45-54 1.67 (1.34-2.00) 0.69 (0.30-1.08) 0.08 (0.00-0.22) 65+ 0.54 (0.25-0.83) 0.33 (0.02-0.64) 0.02 (0.00-0.04) Education ≤12 years 1.78 (1.21-2.35) 0.81 (0.40-1.22) 0.35 (0.04-0.66) >12 years 0.91 (0.69-1.13) 0.47 (0.22-0.72) 0.02 (0.00-0.04) Ethnicity Non-Hispanic White 1.53 (1.18-1.88) 0.59 (0.33-0.85) 0.06 (0.00-0.14) Black 1.26 (0.32-2.20) 0.49 (0.00-0.99) 0.03 (0.00-0.07) Hispanic 0.30 (0.00-0.72) 1.87 (0.00-3.97) 0.70 (0.00-2.07) Other 0.58 (0.16-1.00) 0.31 (0.00-0.63) 0.54 (0.00-1.23) Multi-racial 0.79 (0.19-1.39) 0.16 (0.00-0.47) 0 doi: 10.1371/journal.pone.0079332.t001 made an attempt that lasted for at least 24 hours (both p’s < There are some interesting differences in Table 5. For 0.05). The same is true for snus use: those who are currently example, men are more likely to have heard about e-cigarettes using snus are more likely to have tried to quit smoking than than women, in general. Older people are more likely than those not currently using snus. The former are also more likely younger people to have heard about e-cigarettes from to have made an attempt that lasted for at least 24 hours (both television, while being less likely to have heard about them p’s < 0.05). from the Internet. The same pattern appears in the lower and Table 5 shows data on those reporting having “ever heard of higher education groups. Smokers and recent former smokers e-cigarettes” and where they heard about them. Three quarters are more likely to have heard about e-cigarettes “in-person” of survey respondents, 75.4%, reported that they have heard of than long-term former smokers or never smokers, while the e-cigarettes. The rate of awareness is high across gender, age, latter groups are more likely to have heard about them from education level and ethnicity. Even 69.2% of never smokers television. There is a clear trend that television and in-person have heard about e-cigarettes, and the percentage goes up to are the most common sources of awareness for e-cigarettes. 88.1% for current smokers. Survey respondents can report more than one source of Table 5 also shows that those who have heard about e- awareness of e-cigarettes. However most, 72.1%, reported cigarettes are most likely to report television as their source of only one source when answering the survey. Another 18.4% information, 48.0%. The second most likely source is “in- checked off two sources. The rest, 9.5%, reported three or person conversation”, 38.2%, followed by Internet, 20.7%, and more sources (data not shown in Table 5). radio, 12.2% and social networks, 2.7%. PLOS ONE | www.plosone.org 5 October 2013 | Volume 8 | Issue 10 | e79332 Use and Perception of E-Cigarettes and Snus Table 2. Ever and Current Use of E-Cigarettes and Snus, by Gender and Smoking Status. Long-term former smokers* Never smokers (n=3,254) (n=3,263) Recent former smokers (n=413) Current smokers (n=3,111) % (95% CI) % (95% CI) % (95% CI) % (95% CI) Ever use of e-cigarettes Male 0.97 (0.34-1.60) 1.70 (0.92-2.48) 24.49 (16.94-32.04) 26.99 (23.07-30.91) Female 1.09 (0.48-1.70) 3.17 (2.05-4.29) 29.11 (21.37-36.85) 37.57 (33.55-41.59) Mean 1.04 (0.61-1.47) 2.40 (1.71-3.09) 26.78 (21.35-32.21) 32.18 (29.34-35.05) Ever use of snus Male 2.57 (1.39-3.75) 6.37 (4.76-7.98) 22.93 (14.66-31.20) 17.27 (13.74-20.80) Female 0.50 (0.21-0.79) 0.49 (0.06-0.92) 5.77 (1.77-9.77) 6.08 (3.55-8.61) Mean 1.43 (0.86-2.00) 3.45 (2.66-4.42) 14.43 (9.65-19.21) 11.76 (9.56-13.96) Current use of e-cigarettes Male 0.05 (0.00-0.15) 0.12 (0.00-0.26) 4.97 (1.58-8.36) 4.96 (3.07-6.87) Female 0.03 (0.00-0.09) 0.22 (0.00-0.47) 7.22 (2.79-11.65) 7.61 (5.41-9.81) Mean 0.04 (0.00-0.10) 0.17 (0.03-0.31) 6.08 (3.30-8.86) 6.26 (4.81-7.71) Current use of snus Male 0.56 (0.26-0.85) 0.64 (0.18-1.09) 2.84 (0.18-5.45) 3.20 (2.10-4.30) Female 0.06 (0.00-0.17) 0.23 (0.00-0.50) 0.0 1.70 (0.51-2.82) Mean 0.28 (0.00-0.57) 0.44 (0.11-0.77) 1.44 (0.09-2.79) 2.46 (1.46-3.46) * Ever smokers who quit more than a year ago at the time of survey. Ever smokers who quit within a year or less at the time of survey. doi: 10.1371/journal.pone.0079332.t002 Table 3. Frequency of Using E-Cigarettes and Snus in the Past 30 Days. Never smokers Long-term former smokers Recent former smokers Current smokers Overall % (95% CI) % (95% CI) % (95% CI) % (95% CI) Current use of e-cigarettes (n=267) Every Day 0 31.0 (0.0-71.7) 45.7 (20.9-70.5) 11.5 (3.3-19.7) 16.3 (8.2-24.4) Some Days 100 69.0 (28.3-100.0) 54.3 (29.5-79.1) 88.5 (80.3-96.7) 83.7 (75.6-91.8) Current use of snus (n=80) Every Day 11.3 (0.0-33.8) 75.3 (47.7-100.0) 15.9 (0.0-45.7) 23.2 (1.6-44.8) 27.1 (11.1-43.1) Some Days 88.7 (66.2-100.0) 24.7 (0.0-52.3) 84.1 (54.3-100.0) 76.8 (55.2-98.4) 72.9 (56.9-88.9) * Ever smokers who quit more than a year ago at the time of survey. Ever smokers who quit within a year or less at the time of survey. doi: 10.1371/journal.pone.0079332.t003 Table 4. Reasons for Having Tried E-Cigarettes and Snus . Used either e-cigarettes or snus Used both e-cigarettes and snus E-Cigarettes (n=1,057) Snus (n=316) E-Cigarettes (n=122) Snus (n=122) Safer than cigarettes 49.9 (44.7-55.1) 10.8 (5.9-15.7) 58.2 (44.7-71.7) 26.2 (13.8-38.5) Cheaper than cigarettes 30.3 (25.7-34.9) 24.6 (16.7-32.5) 36.9 (22.8-51.0) 24.8 (13.6-36.0) Easy to use when I can't smoke 44.8 (39.7-49.9) 37.6 (29.2-46.0) 57.4 (43.7-71.1) 49.9 (36.0-63.8) To try to quit smoking cigarettes 54.9 (49.8-60.0) 26.3 (19.0-33.6) 56.9 (43.3-70.5) 30.1 (17.7-42.5) Just because 68.3 (63.8-72.8) 73.8 (66.6-81.0) 72.3 (57.7-85.9) 82.1 (73.3-90.9) * The order of these options was randomized for individual respondents to minimize the order effect in response. doi: 10.1371/journal.pone.0079332.t004 but nearly half, 49.5%, of current smokers are susceptible to Table 6 presents the percentage of population who can be future use of e-cigarettes. Among those who are susceptible, considered susceptible to future e-cigarette use. The an average of 56.4% have tried e-cigarettes but are not “susceptible” category includes all those who had ever tried e- currently using them, 9.5% said they are “very likely” to use cigarettes but were not currently using, and those who have not them, and 34.1 % said “somewhat likely.” experimented with them but are “very likely”, or “somewhat likely” to use them in the future. The proportion of respondents susceptible to future use is dramatically different across smoking status. About 2.6% of never smokers are susceptible, PLOS ONE | www.plosone.org 6 October 2013 | Volume 8 | Issue 10 | e79332 Use and Perception of E-Cigarettes and Snus Figure 2. Quit attempts among current users of E-Cigarettes and Snus versus non-users. doi: 10.1371/journal.pone.0079332.g002 smokers have heard about them, but even two-thirds of never Discussion smokers reported having heard of e-cigarettes. When asked This study, based on a national probability sample, found about where they have heard about these products, television that three quarters of the U.S. adult population have heard tops the list. Internet, which we suspected to be a major driver about e-cigarettes, and approximately 8% of them have for the spread of information about e-cigarettes [12,54], ranks experimented with e-cigarettes. Among current smokers, over third on the list. 30% have ever used e-cigarettes. Of those who have ever tried Since there is little data indicating major television e-cigarettes, about 18% are currently using them, the same advertising paid for by e-cigarette manufacturers before this transition rate as for snus use. However, both the ever use and survey was conducted (in February-March, 2012), the high the current use rates are about twice those for snus. Moreover, level of awareness attributed to television suggests that the those who have tried e-cigarette are twice as likely to report products might have garnered considerable earned media using e-cigarettes as a quitting aid than snus users are to attention. Earned media includes national news programs or report using snus as a quitting aid. E-cigarette users are also health programs that discuss the pros and cons of e-cigarettes significantly more likely to consider e-cigarettes safer than [55-58]. It also includes celebrity endorsements on popular TV conventional cigarettes than snus users are to consider the talk shows [34,35]. And it could include many local television same about snus. Finally, about half of current smokers appear and radio programs, which feed from these national news to be susceptible to e-cigarette use in the future. programs [59-61]. There is, however, no formal documentation That 75% of U.S. population reported being aware of e- of exactly how often this took place, and survey respondents cigarettes is somewhat surprising, given that the survey was might have based their report on what was most salient in their conducted before the onset of any major paid media promotion memory, not what was most frequent. by large tobacco companies. E-cigarettes are presumably One reason for the media’s interest in e-cigarettes may be a mostly of interest to current smokers, or about 20% of the U.S. novelty effect as they are relatively new products in the U.S. population [50]. This survey found that almost 90% of current market. Another reason that e-cigarettes may have attracted PLOS ONE | www.plosone.org 7 October 2013 | Volume 8 | Issue 10 | e79332 Use and Perception of E-Cigarettes and Snus Table 5. Awareness of E-Cigarettes. Ever heard of e- Heard of on Heard of on cigarettes Heard of on radio television Heard of on the Heard of in-person social networks None of the (n=8,045) (n=1,019) (n=3,806) internet (n=1,850) (n=3,178) (n=199) above (n=1,473) % (95% CI) % (95% CI) % (95% CI) % (95% CI) % (95% CI) % (95% CI) % (95% CI) Average 75.4 (74.1-76.7) 12.2 (11.2-13.2) 48.0 (46.4-49.6) 20.7 (19.4-22.0) 38.2 (36.3-39.8) 2.7 (2.1-3.3) 18.0 (16.7-19.3) Gender Male 78.9 (77.1-80.7) 13.8 (12.2-15.4) 49.4 (47.0-51.8) 25.2 (23.2-27.2) 34.2 (32.0-36.4) 2.9 (2.1-3.7) 17.2 (15.4-19.0) Female 72.3 (70.3-74.3) 10.5 (9.1-11.9) 46.6 (44.2-49.0) 16.3 (14.5-18.1) 42.1 (39.7-44.5) 2.6 (1.8-3.4) 18.7 (16.9-20.5) Age 18-24 76.7 (71.8-81.6) 8.9 (5.4-12.4) 41.6 (35.1-48.1) 25.1 (19.4-30.8) 46.0 (39.3-52.7) 3.2 (1.2-5.2) 14.7 (10.4-19.0) 25-44 74.9 (72.4-77.4) 13.2 (11.2-15.2) 40.7 (37.6-43.8) 23.6 (21.1-26.1) 43.5 (40.4-46.6) 3.8 (2.6-5.0) 19.3 (16.8-21.8) 45-64 78.0 (76.2-79.8) 12.3 (10.9-13.7) 52.7 (50.3-55.1) 19.5 (17.7-21.3) 36.0 (33.8-38.2) 1.8 (1.2-2.4) 16.9 (15.1-18.7) 65+ 70.2 (67.7-72.7) 11.3 (9.1-13.5) 57.3 (54.2-60.4) 14.4 (12.4-16.4) 26.2 (23.5-28.9) 2.2 (0.8-3.6) 19.3 (16.8-21.8) Education ≤12 years 73.1 (70.9-75.3) 11.1 (9.5-12.7) 51.8 (49.1-54.5) 17.3 (15.3-19.3) 37.0 (34.5-39.5) 2.7 (1.7-3.7) 15.6 (13.6-17.6) >12 years 77.2 (75.4-79.0) 12.9 (11.5-14.3) 45.3 (43.1-47.5) 23.2 (21.4-25.0) 39.0 (37.0-41.0) 2.7 (1.9-3.5) 19.6 (17.8-21.4) Non- Ethnicity Hispanic 80.6 (79.4-81.8) 12.4 (11.2-13.6) 47.4 (45.6-49.2) 20.2 (18.8-21.6) 38.5 (36.7-40.3) 2.6 (2.0-3.2) 17.4 (16.0-18.8) White Black 62.3 (57.4-67.2) 11.1 (7.8-14.4) 61.1 (55.2-67.0) 20.1 (15.4-24.8) 30.9 (25.4-36.4) 2.4 (0.8-4.0) 19.7 (14.6-24.8) Hispanic 66.2 (59.1-73.3) 17.4 (11.1-23.7) 40.1 (32.3-47.9) 29.7 (22.4-37.0) 39.5 (31.3-47.7) 4.1 (0.6-7.6) 20.0 (13.1-26.9) Other 65.5 (60.8-70.2) 8.4 (5.5-11.3) 45.1 (39.2-51.0) 19.7 (15.0-24.4) 40.3 (34.6-46.0) 2.7 (0.3-5.1) 18.0 (13.7-22.3) Multi-racial 71.6 (62.4-80.8) 18.7 (8.9-28.5) 46.6 (36.4-56.8) 29.7 (19.5-39.9) 49.1 (39.9-59.3) 6.8 (0.0-15.4) 26.8 (16.0-37.6) Smoking Never 69.2 (67.0-71.4) 12.1 (10.5-13.7) 47.5 (44.8-50.2) 18.6 (16.4-20.8) 34.4 (31.9-36.9) 2.6 (1.6-3.6) 19.2 (17.0-21.4) Status LT former 78.7 (76.9-80.5) 11.5 (9.9-13.1) 52.8 (50.3-55.3) 19.2 (17.2-21.2) 34.4 (32.0-36.8) 2.2 (1.4-3.0) 17.3 (15.5-19.1) RT former 85.9 (81.4-90.4) 12.1 (7.6-16.6) 40.8 (34.1-47.5) 27.8 (21.5-34.1) 49.2 (42.3-56.1) 3.9 (1.0-6.8) 14.5 (9.8-19.2) Current 88.1 (85.9-90.3) 13.1 (10.9-15.3) 45.1 (42.0-48.2) 26.1 (23.4-28.8) 49.0 (45.9-52.1) 3.4 (2.2-4.6) 16.4 (14.2-18.6) * Long-term: Ever smokers who quit more than a year ago at the time of survey. Recent-term: Ever smokers who quit within a year or less at the time of survey. doi: 10.1371/journal.pone.0079332.t005 Table 6. Susceptibility to Using E-Cigarettes in the Future . † ‡ Never smokers Long-term former smokers Recent former smokers Current smokers Overall sample (n=3,251) (n=3,256) (n=385) (n=2,882) (n=9,774) % (95% CI) % (95% CI) % (95% CI) % (95% CI) % (95% CI) Not susceptible 97.4 (96.6-98.2) 96.7 (95.9-97.5) 75.1 (69.6-80.6) 50.5 (47.4-53.6) 88.0 (87.1-88.9) All Susceptible 2.6 (1.8-3.4) 3.3 (2.5-4.1) 24.9 (19.4-30.4) 49.5 (46.4-52.6) 12.0 (11.1-12.9) All Susceptible by category Tried e-cigarettes 38.7 (25.4-52.0) 67.1 (56.1-78.1) 88.2 (80.7-95.6) 55.8 (51.5-60.1) 56.4 (52.6-60.2) Very likely 14.9 (7.3-22.5) 16.0 (6.8-25.2) 1.0 (0.0-2.4) 8.8 (6.6-11.0) 9.5 (7.5-11.5) Somewhat likely 46.4 (32.7-60.1) 16.9 (9.1-24.7) 10.8 (3.9-17.7) 35.4 (31.3-39.5) 34.1 (30.5-37.7) * Sample excludes those who reported current use of e-cigarettes. Smokers who quit more than a year ago at the time of survey. Smokers who quit within a year or less at the time of survey. doi: 10.1371/journal.pone.0079332.t006 clearly stoked interest in the products. Both articles included earned media is the intuitive appeal of the products: e- appealing pictures of e-cigarettes. The fact that “in-person cigarettes mimic regular cigarettes in so many ways that it conversation” was the second most frequently reported source seems to be, simply put, a clever invention. For example, as of information (ahead of “Internet”) in the present study also we were preparing the first draft of this paper, articles about e- suggests that many people find the products interesting cigarettes appeared in two highly regarded American enough to raise the topic with friends and colleagues. publications: National Geographic and Consumer Reports [62,63]. Neither article directly promoted e-cigarettes, but both PLOS ONE | www.plosone.org 8 October 2013 | Volume 8 | Issue 10 | e79332 Use and Perception of E-Cigarettes and Snus A limitation of the present study is that members of the users, current users of snus are more likely than non-users to KnowledgePanel sample may engage in more than one survey have made a quit attempt in the last 12 months. in a given year, which might lead to greater familiarity with The proportion of e-cigarette users who believe that e- certain topics. It is possible that the rate of self-reported cigarettes are safer than regular cigarettes is significantly awareness of e-cigarettes might have been inflated for that higher than snus users who believer snus is safer than reason, particularly because the survey described e-cigarettes cigarettes (50% vs. 11%). This perception may be incorrect, before asking if respondents had heard about them. However, but it may have contributed to the large increase in high rates of awareness have also been reported in other experimentation with e-cigarettes from 2010 to 2012, while surveys. For example, a study in England found that 62% and snus use has remained relatively constant. 79% of smokers were aware of e-cigarettes in 2010 and 2012, The contrast in American smokers’ interest in e-cigarettes respectively [5]. Consumer surveys in the U.S. also showed and snus is instructive in many ways. Snus has been an high awareness rate: In 2010 and 2011, awareness of e- established and popular tobacco product in Sweden for many cigarettes was 41% and 58%, respectively [37]. Although the decades. It came to the U.S. market six years before e- consumer survey in the U.S. was not based on a probability cigarettes [68]. It has the support of large U.S. tobacco sample of the entire population, it did show that awareness companies [27]. E-cigarettes, on the other hand, were first increased significantly. With these consumer survey data as a developed in China in 2003 and came to the U.S. market in reference, the high level of awareness found in the present 2007 [4]. Prior to the recent acquisition of the Blu e-cigarette study suggests that interest in e-cigarettes in the U.S. company by Lorillard, e-cigarettes were promoted mainly by continued to grow after 2011, to 75% in 2012 among the U.S small producers. Yet, the use of e-cigarette products has grown population as a whole (Table 5). from half that of snus in 2010 to twice that of snus by 2012. This increase in awareness is supported by the increase in One reason that more smokers are experimenting with e- the rate of ever use of e-cigarettes. The consumer survey cigarettes than with snus, however, appears to be the study, referenced above, reported that 3.3% of respondents in following: e-cigarettes appeal to both men and women while a web-based survey had ever used e-cigarettes in 2010, which snus appeals mainly to men. In fact, e-cigarettes appeal to increased to 6.2% in 2011 [37]. Another smaller but population- women more than men (Table 2). It is possible e-cigarettes are based survey in 2010 reported an ever use rate of 1.8% [64]. perceived as clean nicotine devices, which might appeal to The present study, which was population-based and conducted women more than men. The design and packaging of e- in March 2012, found 8.1% reported ever having used e- cigarettes and e-cigarette promotion that is specifically targeted cigarettes (Figure 1), 3 to 4.5 times higher the rates found in to women may also have contributed to this gender difference 2010. In contrast, ever use of snus has not increased from [69]. In any case, the fact that more women than men have 2010 to 2012. The ever use rates for snus from the two 2010 tried e-cigarettes deserves careful investigation. It is especially surveys cited were 5.4% and 5.1%, respectively [64,65]. The interesting since men are more likely to have heard about e- present study found 4.3% of respondents have ever used snus. cigarettes than women (Table 5). No other so-called potentially In other words, the ever use rate for snus was at least twice as reduced exposure product (PREP) has attracted more women high as that of e-cigarettes in 2010. By 2012, the rate of ever than men. use for e-cigarettes has jumped to be twice as high as that of The most striking contrast, perhaps, is between the adoption snus, and the rate of snus use has remained essentially of e-cigarettes and the adoption of another product that is very unchanged. similar to e-cigarettes. Premier, later called Eclipse, is almost Interestingly, this survey, based on a probability sample of exactly the same as an e-cigarette. It does not involve the U.S. population, found that most current users of e- combustion when smoked [70,71], it looks like a regular cigarettes use them on a non-daily basis. This differs from cigarette, and it lights up when smoked. However, it still uses previous studies that recruited subjects through websites, tobacco leaves. It heats the tobacco leaves to deliver nicotine whose samples are less likely to be representative of all e- to smokers. The product is reported to have cost the R.J. cigarette users [14,66,67]. For example, one online survey of e- Reynolds tobacco company about $1 billion U.S. dollars to cigarette users found 81% of them were daily users [7]. The develop and market test [72]. There was much discussion and present study did find, however, that e-cigarette users who are promotion when the product first came to market [71,73], but it recent former smokers are much more likely to be daily users never quite took off [73]. In contrast, e-cigarettes appear to than those who are still smoking regular cigarettes (Table 5). have tapped into the popular imagination quickly, initially This could be an indication that some of these recent quitters without the backing of any major tobacco company. are using e-cigarettes daily as a replacement for regular This study shows that nearly half of current adult smokers in cigarettes. the U.S. are susceptible to future use of e-cigarettes, and about Over 50% of those who have ever used e-cigarettes reported 25% of the recent former smokers are susceptible. In addition, trying to quit regular cigarettes as one reason they used e- 3.3% of long term former smokers and even 2.6% of adult cigarettes. This is supported by data that current users of e- never smokers are susceptible. While the rates for these latter cigarettes are indeed more likely than non-users to have made two groups are low, the size of these two groups is about 80% an attempt to quit regular cigarettes in the last 12 months of the adult U.S. population. It is not clear what proportion of preceding the survey. A smaller proportion of ever users of youth is susceptible to e-cigarette use. But the number of snus reported trying to quit regular cigarettes. Like e-cigarette potential e-cigarette users among adults is already very large. PLOS ONE | www.plosone.org 9 October 2013 | Volume 8 | Issue 10 | e79332 Use and Perception of E-Cigarettes and Snus All together, the rates in Table 6 translate to 29 million adults in cigarettes is still relatively low, and there has been no study the U.S. susceptible to e-cigarette use. suggesting that their coming to the market has led to any The popularity of e-cigarettes, if it continues to grow, creates detectable change in the quit attempt rate at the population a dilemma for the public health community. On the one hand, level. But more research on e-cigarettes or similar products e-cigarettes are a new kind of tobacco-based product that is that have a strong intuitive appeal may help in developing a completely unregulated. There are numerous brands currently conceptual model and corresponding policy to increase the on market, easily purchased over the Internet or even in gas population cessation rate. stations and convenience stores [74]. The ingredients of most The case of e-cigarettes and their rapid adoption, in brands are not reported. Safety data are lacking. Their efficacy conjunction with the lack of scientific data on safety and for helping smokers to quit regular cigarettes is not well efficacy, presents a difficult regulatory problem. It is imperative established. Their potential negative impact on tobacco control that the scientific community rise to the challenge. The usual norms is unknown, especially their potential to induce approach to research for any product intended to help smokers adolescent nonsmokers to take up tobacco-based products. quit using regular cigarettes proceeds from safety to efficacy. Meanwhile, many smokers believe e-cigarettes are safer than Such a process usually takes many years, and millions may be regular cigarettes. Many have used them with the hope that using e-cigarettes before that process is completed. Studies they would help them quit smoking regular cigarettes. A are needed to assess risks and benefits of these new products substantial proportion of smokers also find e-cigarettes for individual users more rapidly. Equally important, studies are cheaper than regular cigarettes (Table 4), which can contribute needed to identify factors that influence the population use to the popularity of the former. All of these data suggest that patterns and to determine how individual preference for various smokers in the U.S. are not waiting for a consensus view from products translates into benefit or harm on the population level. health authorities to decide if they should switch to e-cigarettes. Acknowledgements The results of the present study and those of previous studies suggest that e-cigarettes are likely to gain users in the next few We would like to thank David Cowling for his assistance in years regardless of the opinions of the scientific community. questionnaire design and statistical analysis. We would also The fact that e-cigarettes have quickly surpassed snus in like to thank Gary Tedeschi, Yue-Lin Zhuang, and Christopher perceptions related to safety and utility, and in actual use Anderson for their comments on earlier drafts of the among U.S. smokers suggests that some feature of e- manuscript. cigarettes must have tapped into smokers’ intuitive preferences. Whether these beliefs are correct or not, they Author Contributions could potentially be channeled into a productive public health campaign to increase the rate of current smokers trying to quit Conceived and designed the experiments: SHZ. Analyzed the cigarettes. Given that the population smoking cessation rate data: SHZ AG LY ML. Wrote the manuscript: SHZ AG SC ML has not improved in the last twenty years in the U.S., any LY LZ. Survey Design: SHZ SC LZ. measure that could increase the rate of smokers attempting to quit deserves consideration [75]. The rate of current use of e- References 1. 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PubMed: PLOS ONE | www.plosone.org 12 October 2013 | Volume 8 | Issue 10 | e79332 http://www.deepdyve.com/assets/images/DeepDyve-Logo-lg.png PLoS ONE Pubmed Central

The Use and Perception of Electronic Cigarettes and Snus among the U.S. Population

Zhu, Shu-Hong; Gamst, Anthony; Lee, Madeleine; Cummins, Sharon; Yin, Lu; Zoref, Leslie
PLoS ONE , Volume 8 (10) – Oct 24, 2013
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© 2013 Zhu et al
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1932-6203
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1932-6203
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10.1371/journal.pone.0079332
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Abstract

Background: E-cigarettes have generated controversy in the tobacco control field similar to that of Swedish snus, which came to the U.S. market six years earlier. Some argue that e-cigarettes have great potential to help smokers quit regular cigarettes while others contend they should be banned for lack of safety and efficacy data. This study examined population data from the U.S. Methods: A U.S. population survey with a national probability sample (N=10,041) was conducted (February 24 to March 8, 2012, before any major paid advertisement of e-cigarettes appeared on television). Survey respondents were asked if they had heard about e-cigarettes, where they had heard about them, whether they had used e- cigarettes or snus, how often they used them, and why they used them. Responses were weighted to represent the entire U.S. population. Findings: A high proportion, 75.4%, reported having heard about e-cigarettes. Television ranked as the number one source of information, followed by “in-person conversation” and “Internet.” About 8.1% had tried e-cigarettes, and 1.4% were current users. These rates were twice those of snus (4.3% and 0.8%, respectively). Among current smokers, 32.2% had tried e-cigarettes, and 6.3% were current users. Over 80% of current e-cigarette users were non-daily users. Women were significantly more likely to have tried e-cigarettes than men. Those who had tried e- cigarettes were more likely than those who tried snus to report their products being safer than regular cigarettes (49.9% vs. 10.8%). Almost half (49.5%) of current smokers were susceptible to using e-cigarettes in the future. Conclusions: That e-cigarettes have surpassed snus in adoption rate, even before any promotion by major tobacco companies, suggests that the former have tapped into smokers’ intuitive preference for potentially harm-reducing products, probably due to the product design. E-cigarette use is likely to increase in the next few years. Citation: Zhu S-H, Gamst A, Lee M, Cummins S, Yin L, et al. (2013) The Use and Perception of Electronic Cigarettes and Snus among the U.S. Population . PLoS ONE 8(10): e79332. doi:10.1371/journal.pone.0079332 Editor: Alan Blum, University of Alabama, United States of America Received July 16, 2012; Accepted October 1, 2013; Published October 24, 2013 Copyright: © 2013 Zhu et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. Funding: This work was supported by a grant from the National Cancer Institute (http://www.cancer.gov), U01 CA154280. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript. Competing interests: The authors have declared that no competing interests exist. * E-mail: [email protected] Introduction help them quit smoking abound [3,7,12-14], but efficacy data in the form of clinical trials are still limited [15-19]. The Electronic Nicotine Delivery System (ENDS), also known Insufficient scientific research on the safety and efficacy of e- as the e-cigarette, has increasingly attracted the attention of cigarettes is one reason that the products have attracted smokers and tobacco control workers [1,2]. E-cigarettes were controversy. Some countries have banned the sale of e- first developed in China in 2003 [3]. They came to the U.S. cigarettes [20], although that does not prevent smokers from market in 2007 and quickly gained notoriety in many countries, purchasing them on the Internet. In the U.S., the Food and especially those with relatively strong tobacco control programs Drug Administration (FDA) has attempted to regulate the sale [4-9]. Unfortunately, scientific information about e-cigarettes is and marketing of e-cigarettes, a move that was struck down by limited. Some argue that e-cigarettes are obviously less a federal court [21]. Short of FDA regulatory oversight, some harmful than cigarettes and have great potential to help states have tried to pass laws to ban the sale of e-cigarettes in smokers quit [10,11], while others contend that data on safety their own jurisdictions [22] although the availability of e- are needed before e-cigarettes are promoted or allowed to be cigarettes on the Internet makes it difficult to enforce such a sold [1]. Anecdotal reports of smokers using e-cigarettes to ban. Meanwhile, the rationale for the ban itself appears to be PLOS ONE | www.plosone.org 1 October 2013 | Volume 8 | Issue 10 | e79332 Use and Perception of E-Cigarettes and Snus chiefly based on predicted potential harm, as empirical Methods evidence is sparse [11]. This controversy surrounding e-cigarettes is reminiscent of Ethics Statement the controversy associated with another tobacco product, snus. This research was performed in accordance with a human Snus, a moist smokeless tobacco product popular in Sweden, subjects protocol approved by the University of California, San gained the attention of global tobacco control workers a few Diego’s Institutional Review Board (IRB# 111664). years before e-cigarettes did [23]. Strong arguments for and Data source against snus have been advanced, but the tobacco control field remains divided [24-27]. Especially difficult is the debate on the The data for this study was obtained from a survey potential of snus to reduce the harm of tobacco use at the commissioned by the University of California, San Diego and administered by Knowledge Networks (Menlo Park, CA). population level [27]. While using snus may be less risky than Knowledge Networks, which was recently acquired by GfK, smoking cigarettes to the health of the individual, it is not clear recruits a probability sample representative of the U.S. that promoting the use of snus would reduce the total harm population (KnowledgePanel). The sample was originally associated with tobacco use at the population level [28,29]. recruited by random digit dialing (RDD) but an address-based Some have argued that promoting the use of any tobacco sampling methodology has been used in recent years [38]. A product supports the tobacco-use norm and, as such, would detailed description of the sampling methods used to recruit to produce a negative net-effect on tobacco control at the the KnowledgePanel has been described elsewhere [39]. The population level [27]. Similar difficulty exists in the current advantages and the limitations of using the KnowledgePanel controversy on e-cigarettes. have also been discussed in many contexts and will not be There is, however, one noticeable difference in the short repeated here [40-42]. In summary, the panel provides an history of e-cigarettes and snus in the U.S. market. E-cigarettes efficient way of accessing a probability sample of the U.S. seem to have achieved notoriety relatively quickly without population, whose representativeness is similar to most other major paid advertising [30]. Unlike snus, which has been well-known population surveys [42-46]. All Knowledge promoted by large tobacco companies in the U.S. [31,32], e- Networks surveys are performed online. Knowledge Networks provides a netbook computer and network access to cigarettes had not been promoted by any major tobacco participants, as needed. Many health behavior studies have company until Lorillard Inc. acquired a major brand Blu-Cigs in used the KnowledgePanel [45,47,48]. April 2012 [33]. Instead, e-cigarettes appear to have received The present survey was designed to gather information on much free publicity. No study has carefully documented the smoking history and cigarette use, perceptions about different level of paid advertising versus earned media for e-cigarettes. tobacco products and quitting aids, attitudes toward tobacco But a quick web search will show that e-cigarettes have control efforts, and beliefs and ideation about the process of received much free coverage. For example, endorsements quitting smoking. The study over sampled the smokers in the have come from some American celebrities and talk show KnowledgePanel so that all the available smokers were hosts, who tout e-cigarettes’ intuitive appeal and how they can included, with a random sub-sample of former smokers and help smokers quit cigarettes [34,35]. E-cigarettes have never smokers from the panel such that the three smoking- appeared in popular movies [35,36]. By 2010, web searches for status groups were approximately equal in size. A total of information on e-cigarettes in that year had surpassed those for 15,095 adults (> 18 years of age) were sampled and invited to snus in the U.S. [6] All this suggests that the adoption of e- participate in the survey. Of these, 10,041 completed the cigarettes may be significant, and a comparison with the survey, a response rate of 66.5%. This corresponds to a sample with 3,111 current smokers, 3,676 former smokers and adoption of snus will be informative. 3,254 never smokers. The survey was conducted between The present study aimed to provide some basic measures on th th February 24 and March 8 , 2012. how much of a foot-hold e-cigarettes had already taken among the U.S. population before Lorillard Inc. purchased a well- Measurement known e-cigarette brand and started a significant television Cigarette smoking behavior was assessed in multiple advertising campaign [33,37]. Using a survey of a probability questions. Current smokers were defined as those who had sample of the U.S. population, this study examined the smoked at least 100 cigarettes in their lifetime and who knowledge about e-cigarettes among smokers and answered the question, “Do you currently smoke cigarettes nonsmokers. It provided population prevalence measures on every day, some days, or not at all?” with “every day” or “some ever and current use of e-cigarettes and the rate of transition days”. Those who had smoked at least 100 cigarettes in their from ever use to current use. The perceived utility of e- lifetime and answered “not at all” were classified as former cigarettes as a quitting aid or as a potential harm reduction smokers. Former smokers were further asked, “When did you product was assessed and compared with that of snus, a smoke your last cigarette?” They were categorized as recent potential harm reduction product that aroused similar former smokers if they selected any of the options with a time controversy when it came to the U.S. a few years before e- frame of 1 year or less, and long-term former smokers if they cigarettes. Finally, the proportion of the U.S. population that is answered “Over 1 year ago”. Nonsmokers were defined as susceptible to future e-cigarettes was estimated. those who had not smoked 100 cigarettes in their lifetime. PLOS ONE | www.plosone.org 2 October 2013 | Volume 8 | Issue 10 | e79332 Use and Perception of E-Cigarettes and Snus Current smokers were asked if they had ever tried to quit survey-specific sampling design. In this case, this survey had smoking, and if they answered yes, were also asked whether approximately equal numbers of current smokers, former they had tried to quit in the last 12 months. smokers, and never smokers. The adjustment for over- Use of snus was assessed by the question, “Have you ever sampling of smokers produced an overall smoking prevalence used any of the following tobacco products?” for which “Snus for the U.S. of 19.1% based on this survey, which is quite close (tobacco in a small pouch, like Camel snus or Marlboro snus)” to the newest published national estimate of 19.3% based on was one of the available options. Those who selected “yes” the 2010 National Health Interview Survey [50]. All results were were defined as ever users of snus and asked the question “Do analyzed by demographic categories (gender, age, educational you currently use snus every day, some days, or not at all?” level, ethnic background), as well as by smoking status. Those selected “every day” or “some days” were defined as Standard errors were calculated and 95% confidence intervals current users of snus. were computed based on the sampling distribution of the Use of e-cigarettes was also assessed in multiple questions. corresponding summary statistic. Confidence intervals for First, respondents were asked if they have ever heard of e- binomial proportions were computed using the method of cigarettes: “E-cigarettes (electronic cigarettes) are electronic Agresti and Coull ([51]; see also 52). All calculations were done devices that deliver nicotine in a vapor and look like cigarettes, using R 2.12.1 [53]. but contain no tobacco. Have you ever heard of e-cigarettes?” Those who had heard of e-cigarettes were also asked where Results they had heard about e-cigarettes and were allowed to select one or more of the following options: “Radio”, “TV”, “Internet”, Figure 1 shows the rate of having “ever used” and “currently “In-person conversation”, “Information shared via Facebook, use” for e-cigarettes and snus, weighted to the U.S. population. YouTube, or other social network media”, and “Other”. A total of 8.08% reported that they had ever used e-cigarettes, Additionally, those who had heard of e-cigarettes were and 1.44% reported currently using e-cigarettes. Thus, asked: “Have you ever tried an e-cigarette”, and those who approximately 18% of those who have ever used e-cigarettes answered yes were considered ever users. Ever users were continue as current users (1.44/8.08 =17.8%). also asked “Have you used e-cigarettes in the last 30 days”, The rate of ever used and current use for snus is and those who answered yes were considered current users. approximately half that of e-cigarettes: 4.26% and 0.77%, Current users were asked to provide the number of days (in the respectively. The rate of transition from ever users of snus to last 30) they had used e-cigarettes. current users, however, is about the same, 18% (0.77/4.26 = Ever users of e-cigarettes were asked “Why did you use e- 18.1%). cigarettes?” and instructed to select “Yes” or “No” for each of Table 1 presents the usage rates of e-cigarettes and snus by the following options: “Safer than cigarettes”, “Cheaper than demographic categories. It also separates out those who used cigarettes,” “Easy to use when I can’t smoke,” “To try to quit only e-cigarettes or snus from those who used both products. smoking cigarettes”, or “Just because.” Since a person could The top half of the table shows the “ever use” rates. Women have multiple reasons for using any product, the order of these are more likely to have ever used e-cigarettes than men. The options was randomized by individual respondent to minimize usage rate is higher among the young and those with lower the order effect in response (e.g., respondent may be more education. Hispanics are less likely to have ever used e- likely to choose the first option on the list). The “just because” cigarettes than either Whites or Blacks. option was included to make clear that the respondent need The usage rates for snus are significantly lower. The main not have any particular reason. difference is in gender: About the same percentage of men Finally, those who had never used e-cigarettes were asked have tried e-cigarettes or snus: 7.17 % (5.33% + 1.84%) for e- the question: “How likely are you to try e-cigarettes in the cigarettes and 7.10% (5.26% + 1.84%) for snus. However, the future?” This was intended to assess their susceptibility to e- percentage of women having tried e-cigarettes is much higher cigarettes, much like the susceptibility measure on uptake of than for snus 8.92% (8.33% + 0.59%) versus 1.65% (1.06% + regular cigarettes [49]. Those who responded that they were 0.59%). “Very likely” or “Somewhat likely” were considered to be The bottom half of Table 1 shows the rates of current use. susceptible. This is slightly stricter definition than the The demographic pattern for the “currently use” is similar to susceptibility measure used in the literature for uptake of that for “ever used” except that the rates for the former are cigarettes in that the present definition does not include those significantly lower across all demographic categories. who responded “somewhat unlikely” [49]. The susceptibility Table 2 shows the rates of ever used and current use by definition here does include those who have tried e-cigarettes smoking status and by gender. In this table, all users of e- but are not currently using them. cigarettes are combined into one group regardless of whether they use snus or not. The same is done for snus users: They Analysis are combined into one group of snus users regardless of their All percentages were weighted by population parameters e-cigarette use status (thus, dual users are counted in both calculations). based on the most recent U.S. Current Population Survey [46]. A survey-specific post-stratification adjustment was used to Table 2 shows that the difference in usage rates by smoking account for any survey non-response, as well as any non- status is large. About 1% of never smokers have ever tried e- coverage or under- and over-sampling resulting from the cigarettes, while over 32% of current smokers have used e- PLOS ONE | www.plosone.org 3 October 2013 | Volume 8 | Issue 10 | e79332 Use and Perception of E-Cigarettes and Snus Figure 1. The rates of ever use and current use of E-Cigarettes and Snus. doi: 10.1371/journal.pone.0079332.g001 cigarettes. The same is true with ever using snus. Clearly, Most snus users used snus on a non-daily basis. Among the long-term former smokers, however, most used snus on a daily recent former smokers and current smokers are the most likely basis. to have tried e-cigarette or snus. Table 4 shows the reasons of use, reported by the ever e- There is also a significant gender difference in ever using e- cigarette users and ever snus users. It is useful to take a look cigarettes or snus. This gender difference is most clearly seen at those who used both products, first (the last two columns of among the current smokers: women are more likely to have the table). The most common reason for having tried e- tried e-cigarettes than men (about 38% vs. 27%). In contrast, cigarettes or snus is “just because:” 72.3% for e-cigarettes and men are more likely to have tried snus (about 17% vs. 6%). It 82.1% for snus. For e-cigarettes, the second most common should be noted, however, that both women and men are more reason given is “to try to quit smoking cigarettes,” followed by likely to have tried e-cigarettes than snus. “safer than cigarettes” and “easy to use when I can’t smoke.” Table 2 also shows that the current use rates have a similar For snus, the second most common reason is “easy to use pattern to the ever use rates. It is recent former smokers and when I can’t smoke,” “followed by to try to quit smoking current smokers who are more likely to be current users of e- cigarettes.” Overall, the dual users are significantly more likely cigarettes or snus. The gender difference between e-cigarette to report use of e-cigarettes than snus to quit smoking, 56.9% vs. 30.1%. Dual users are more likely to report the belief that e- and snus use is reversed in this comparison, but the difference cigarettes are safer than cigarettes, 58.2% vs. 26.2% for snus. is not statistically significant. The overall rates, however, are The patterns for those using either e-cigarettes only or snus significantly higher for e-cigarettes than for snus among recent only are presented in columns 1 and 2, and they are similar to formers smokers and current smokers. that of dual users. E-cigarette users are about twice as likely as Table 3 shows the frequency of use for e-cigarettes or snus snus users to report using the product “to try to quit smoking” among those who currently use either of these two types of (54.9% vs. 26.3%). The former are also significantly more likely products. Among e-cigarette users, there is a significant to believe e-cigarettes are safer than regular cigarettes than difference in the use pattern between current smokers and the latter are to believe snus is safer than cigarettes (49.9% vs. recent former smokers. Among current smokers, those who 10.8%). used e-cigarettes were mostly occasional users, only 11.5% of Figure 2 shows that those who are currently using e- used e-cigarettes daily. Among recent former smokers, cigarettes are significantly more likely to have tried to quit however, 45.7% used them on a daily basis, a statistically smoking in the last 12 months than those who are currently not significant difference (p<0.05). using e-cigarettes. The former are also more likely to have PLOS ONE | www.plosone.org 4 October 2013 | Volume 8 | Issue 10 | e79332 Use and Perception of E-Cigarettes and Snus Table 1. Ever and Current Use of E-Cigarettes and Snus (n = 10,041). Ever Use E-cigarettes only Snus only E-Cigarettes and Snus % (95% CI) % (95% CI) % (95% CI) Mean 6.89 (6.40-7.39) 3.07 (2.73-3.41) 1.19 (0.98-1.40) Gender Male 5.33 (4.51-6.15) 5.26 (4.32-6.20) 1.84 (1.25-2.43) Female 8.33 (7.33-9.33) 1.06 (0.63-1.49) 0.59 (0.28-0.90) Age 18-24 9.33 (6.59-12.07) 3.54 (1.60-5.48) 3.37 (1.49-5.25) 25-44 7.78 (6.43-9.13) 3.98 (2.92-5.04) 1.69 (1.02-2.36) 45-54 7.35 (6.47-8.23) 2.88 (2.23-3.53) 0.52 (0.28-0.76) 65+ 2.62 (19.3-3.31) 1.25 (0.78-1.72) 0.34 (0.00-0.69) Education ≤12 years 8.60 (7.37-9.83) 3.48 (2.60-4.36) 1.61 (1.23-1.99) >12 years 5.63 (4.94-6.32) 2.76 (2.17-3.35) 0.88 (0.61-1.15) Ethnicity Non-Hispanic White 7.02 (6.29-7.75) 3.27 (2.66-3.88) 1.32 (0.91-1.73) Black 8.12 (5.55-10.69) 1.19 (0.39-1.99) 0.35 (0.00-0.74) Hispanic 4.38 (1.81-6.95) 4.40 (1.64-7.16) 1.42 (0.00-3.07) Other 6.14 (4.87-7.40) 2.94 (1.43-4.45) 1.22 (0.64-1.80) Multi-racial 9.51 (5.24-13.78) 4.69 (0.97-8.41) 0.52 (0.00-1.07) Current Use E-cigarettes only Snus only E-Cigarettes and Snus % (95% CI) % (95% CI) % (95% CI) Mean 1.28 (1.06-1.50) 0.61 (0.46-0.76) 0.16 (0.08-0.24) Gender Male 1.00 (0.65-1.35) 0.96 (0.53-1.39) 0.22 (0.00-0.46) Female 1.54 (1.13-1.95) 0.29 (0.11-0.47) 0.10 (0.00-0.26) Age 18-24 1.47 (0.33-2.61) 0.27 (0.00-0.58) 0.23 (0.00-0.48) 25-44 1.19 (0.62-1.76) 0.75 (0.28-1.22) 0.29 (0.00-0.62) 45-54 1.67 (1.34-2.00) 0.69 (0.30-1.08) 0.08 (0.00-0.22) 65+ 0.54 (0.25-0.83) 0.33 (0.02-0.64) 0.02 (0.00-0.04) Education ≤12 years 1.78 (1.21-2.35) 0.81 (0.40-1.22) 0.35 (0.04-0.66) >12 years 0.91 (0.69-1.13) 0.47 (0.22-0.72) 0.02 (0.00-0.04) Ethnicity Non-Hispanic White 1.53 (1.18-1.88) 0.59 (0.33-0.85) 0.06 (0.00-0.14) Black 1.26 (0.32-2.20) 0.49 (0.00-0.99) 0.03 (0.00-0.07) Hispanic 0.30 (0.00-0.72) 1.87 (0.00-3.97) 0.70 (0.00-2.07) Other 0.58 (0.16-1.00) 0.31 (0.00-0.63) 0.54 (0.00-1.23) Multi-racial 0.79 (0.19-1.39) 0.16 (0.00-0.47) 0 doi: 10.1371/journal.pone.0079332.t001 made an attempt that lasted for at least 24 hours (both p’s < There are some interesting differences in Table 5. For 0.05). The same is true for snus use: those who are currently example, men are more likely to have heard about e-cigarettes using snus are more likely to have tried to quit smoking than than women, in general. Older people are more likely than those not currently using snus. The former are also more likely younger people to have heard about e-cigarettes from to have made an attempt that lasted for at least 24 hours (both television, while being less likely to have heard about them p’s < 0.05). from the Internet. The same pattern appears in the lower and Table 5 shows data on those reporting having “ever heard of higher education groups. Smokers and recent former smokers e-cigarettes” and where they heard about them. Three quarters are more likely to have heard about e-cigarettes “in-person” of survey respondents, 75.4%, reported that they have heard of than long-term former smokers or never smokers, while the e-cigarettes. The rate of awareness is high across gender, age, latter groups are more likely to have heard about them from education level and ethnicity. Even 69.2% of never smokers television. There is a clear trend that television and in-person have heard about e-cigarettes, and the percentage goes up to are the most common sources of awareness for e-cigarettes. 88.1% for current smokers. Survey respondents can report more than one source of Table 5 also shows that those who have heard about e- awareness of e-cigarettes. However most, 72.1%, reported cigarettes are most likely to report television as their source of only one source when answering the survey. Another 18.4% information, 48.0%. The second most likely source is “in- checked off two sources. The rest, 9.5%, reported three or person conversation”, 38.2%, followed by Internet, 20.7%, and more sources (data not shown in Table 5). radio, 12.2% and social networks, 2.7%. PLOS ONE | www.plosone.org 5 October 2013 | Volume 8 | Issue 10 | e79332 Use and Perception of E-Cigarettes and Snus Table 2. Ever and Current Use of E-Cigarettes and Snus, by Gender and Smoking Status. Long-term former smokers* Never smokers (n=3,254) (n=3,263) Recent former smokers (n=413) Current smokers (n=3,111) % (95% CI) % (95% CI) % (95% CI) % (95% CI) Ever use of e-cigarettes Male 0.97 (0.34-1.60) 1.70 (0.92-2.48) 24.49 (16.94-32.04) 26.99 (23.07-30.91) Female 1.09 (0.48-1.70) 3.17 (2.05-4.29) 29.11 (21.37-36.85) 37.57 (33.55-41.59) Mean 1.04 (0.61-1.47) 2.40 (1.71-3.09) 26.78 (21.35-32.21) 32.18 (29.34-35.05) Ever use of snus Male 2.57 (1.39-3.75) 6.37 (4.76-7.98) 22.93 (14.66-31.20) 17.27 (13.74-20.80) Female 0.50 (0.21-0.79) 0.49 (0.06-0.92) 5.77 (1.77-9.77) 6.08 (3.55-8.61) Mean 1.43 (0.86-2.00) 3.45 (2.66-4.42) 14.43 (9.65-19.21) 11.76 (9.56-13.96) Current use of e-cigarettes Male 0.05 (0.00-0.15) 0.12 (0.00-0.26) 4.97 (1.58-8.36) 4.96 (3.07-6.87) Female 0.03 (0.00-0.09) 0.22 (0.00-0.47) 7.22 (2.79-11.65) 7.61 (5.41-9.81) Mean 0.04 (0.00-0.10) 0.17 (0.03-0.31) 6.08 (3.30-8.86) 6.26 (4.81-7.71) Current use of snus Male 0.56 (0.26-0.85) 0.64 (0.18-1.09) 2.84 (0.18-5.45) 3.20 (2.10-4.30) Female 0.06 (0.00-0.17) 0.23 (0.00-0.50) 0.0 1.70 (0.51-2.82) Mean 0.28 (0.00-0.57) 0.44 (0.11-0.77) 1.44 (0.09-2.79) 2.46 (1.46-3.46) * Ever smokers who quit more than a year ago at the time of survey. Ever smokers who quit within a year or less at the time of survey. doi: 10.1371/journal.pone.0079332.t002 Table 3. Frequency of Using E-Cigarettes and Snus in the Past 30 Days. Never smokers Long-term former smokers Recent former smokers Current smokers Overall % (95% CI) % (95% CI) % (95% CI) % (95% CI) Current use of e-cigarettes (n=267) Every Day 0 31.0 (0.0-71.7) 45.7 (20.9-70.5) 11.5 (3.3-19.7) 16.3 (8.2-24.4) Some Days 100 69.0 (28.3-100.0) 54.3 (29.5-79.1) 88.5 (80.3-96.7) 83.7 (75.6-91.8) Current use of snus (n=80) Every Day 11.3 (0.0-33.8) 75.3 (47.7-100.0) 15.9 (0.0-45.7) 23.2 (1.6-44.8) 27.1 (11.1-43.1) Some Days 88.7 (66.2-100.0) 24.7 (0.0-52.3) 84.1 (54.3-100.0) 76.8 (55.2-98.4) 72.9 (56.9-88.9) * Ever smokers who quit more than a year ago at the time of survey. Ever smokers who quit within a year or less at the time of survey. doi: 10.1371/journal.pone.0079332.t003 Table 4. Reasons for Having Tried E-Cigarettes and Snus . Used either e-cigarettes or snus Used both e-cigarettes and snus E-Cigarettes (n=1,057) Snus (n=316) E-Cigarettes (n=122) Snus (n=122) Safer than cigarettes 49.9 (44.7-55.1) 10.8 (5.9-15.7) 58.2 (44.7-71.7) 26.2 (13.8-38.5) Cheaper than cigarettes 30.3 (25.7-34.9) 24.6 (16.7-32.5) 36.9 (22.8-51.0) 24.8 (13.6-36.0) Easy to use when I can't smoke 44.8 (39.7-49.9) 37.6 (29.2-46.0) 57.4 (43.7-71.1) 49.9 (36.0-63.8) To try to quit smoking cigarettes 54.9 (49.8-60.0) 26.3 (19.0-33.6) 56.9 (43.3-70.5) 30.1 (17.7-42.5) Just because 68.3 (63.8-72.8) 73.8 (66.6-81.0) 72.3 (57.7-85.9) 82.1 (73.3-90.9) * The order of these options was randomized for individual respondents to minimize the order effect in response. doi: 10.1371/journal.pone.0079332.t004 but nearly half, 49.5%, of current smokers are susceptible to Table 6 presents the percentage of population who can be future use of e-cigarettes. Among those who are susceptible, considered susceptible to future e-cigarette use. The an average of 56.4% have tried e-cigarettes but are not “susceptible” category includes all those who had ever tried e- currently using them, 9.5% said they are “very likely” to use cigarettes but were not currently using, and those who have not them, and 34.1 % said “somewhat likely.” experimented with them but are “very likely”, or “somewhat likely” to use them in the future. The proportion of respondents susceptible to future use is dramatically different across smoking status. About 2.6% of never smokers are susceptible, PLOS ONE | www.plosone.org 6 October 2013 | Volume 8 | Issue 10 | e79332 Use and Perception of E-Cigarettes and Snus Figure 2. Quit attempts among current users of E-Cigarettes and Snus versus non-users. doi: 10.1371/journal.pone.0079332.g002 smokers have heard about them, but even two-thirds of never Discussion smokers reported having heard of e-cigarettes. When asked This study, based on a national probability sample, found about where they have heard about these products, television that three quarters of the U.S. adult population have heard tops the list. Internet, which we suspected to be a major driver about e-cigarettes, and approximately 8% of them have for the spread of information about e-cigarettes [12,54], ranks experimented with e-cigarettes. Among current smokers, over third on the list. 30% have ever used e-cigarettes. Of those who have ever tried Since there is little data indicating major television e-cigarettes, about 18% are currently using them, the same advertising paid for by e-cigarette manufacturers before this transition rate as for snus use. However, both the ever use and survey was conducted (in February-March, 2012), the high the current use rates are about twice those for snus. Moreover, level of awareness attributed to television suggests that the those who have tried e-cigarette are twice as likely to report products might have garnered considerable earned media using e-cigarettes as a quitting aid than snus users are to attention. Earned media includes national news programs or report using snus as a quitting aid. E-cigarette users are also health programs that discuss the pros and cons of e-cigarettes significantly more likely to consider e-cigarettes safer than [55-58]. It also includes celebrity endorsements on popular TV conventional cigarettes than snus users are to consider the talk shows [34,35]. And it could include many local television same about snus. Finally, about half of current smokers appear and radio programs, which feed from these national news to be susceptible to e-cigarette use in the future. programs [59-61]. There is, however, no formal documentation That 75% of U.S. population reported being aware of e- of exactly how often this took place, and survey respondents cigarettes is somewhat surprising, given that the survey was might have based their report on what was most salient in their conducted before the onset of any major paid media promotion memory, not what was most frequent. by large tobacco companies. E-cigarettes are presumably One reason for the media’s interest in e-cigarettes may be a mostly of interest to current smokers, or about 20% of the U.S. novelty effect as they are relatively new products in the U.S. population [50]. This survey found that almost 90% of current market. Another reason that e-cigarettes may have attracted PLOS ONE | www.plosone.org 7 October 2013 | Volume 8 | Issue 10 | e79332 Use and Perception of E-Cigarettes and Snus Table 5. Awareness of E-Cigarettes. Ever heard of e- Heard of on Heard of on cigarettes Heard of on radio television Heard of on the Heard of in-person social networks None of the (n=8,045) (n=1,019) (n=3,806) internet (n=1,850) (n=3,178) (n=199) above (n=1,473) % (95% CI) % (95% CI) % (95% CI) % (95% CI) % (95% CI) % (95% CI) % (95% CI) Average 75.4 (74.1-76.7) 12.2 (11.2-13.2) 48.0 (46.4-49.6) 20.7 (19.4-22.0) 38.2 (36.3-39.8) 2.7 (2.1-3.3) 18.0 (16.7-19.3) Gender Male 78.9 (77.1-80.7) 13.8 (12.2-15.4) 49.4 (47.0-51.8) 25.2 (23.2-27.2) 34.2 (32.0-36.4) 2.9 (2.1-3.7) 17.2 (15.4-19.0) Female 72.3 (70.3-74.3) 10.5 (9.1-11.9) 46.6 (44.2-49.0) 16.3 (14.5-18.1) 42.1 (39.7-44.5) 2.6 (1.8-3.4) 18.7 (16.9-20.5) Age 18-24 76.7 (71.8-81.6) 8.9 (5.4-12.4) 41.6 (35.1-48.1) 25.1 (19.4-30.8) 46.0 (39.3-52.7) 3.2 (1.2-5.2) 14.7 (10.4-19.0) 25-44 74.9 (72.4-77.4) 13.2 (11.2-15.2) 40.7 (37.6-43.8) 23.6 (21.1-26.1) 43.5 (40.4-46.6) 3.8 (2.6-5.0) 19.3 (16.8-21.8) 45-64 78.0 (76.2-79.8) 12.3 (10.9-13.7) 52.7 (50.3-55.1) 19.5 (17.7-21.3) 36.0 (33.8-38.2) 1.8 (1.2-2.4) 16.9 (15.1-18.7) 65+ 70.2 (67.7-72.7) 11.3 (9.1-13.5) 57.3 (54.2-60.4) 14.4 (12.4-16.4) 26.2 (23.5-28.9) 2.2 (0.8-3.6) 19.3 (16.8-21.8) Education ≤12 years 73.1 (70.9-75.3) 11.1 (9.5-12.7) 51.8 (49.1-54.5) 17.3 (15.3-19.3) 37.0 (34.5-39.5) 2.7 (1.7-3.7) 15.6 (13.6-17.6) >12 years 77.2 (75.4-79.0) 12.9 (11.5-14.3) 45.3 (43.1-47.5) 23.2 (21.4-25.0) 39.0 (37.0-41.0) 2.7 (1.9-3.5) 19.6 (17.8-21.4) Non- Ethnicity Hispanic 80.6 (79.4-81.8) 12.4 (11.2-13.6) 47.4 (45.6-49.2) 20.2 (18.8-21.6) 38.5 (36.7-40.3) 2.6 (2.0-3.2) 17.4 (16.0-18.8) White Black 62.3 (57.4-67.2) 11.1 (7.8-14.4) 61.1 (55.2-67.0) 20.1 (15.4-24.8) 30.9 (25.4-36.4) 2.4 (0.8-4.0) 19.7 (14.6-24.8) Hispanic 66.2 (59.1-73.3) 17.4 (11.1-23.7) 40.1 (32.3-47.9) 29.7 (22.4-37.0) 39.5 (31.3-47.7) 4.1 (0.6-7.6) 20.0 (13.1-26.9) Other 65.5 (60.8-70.2) 8.4 (5.5-11.3) 45.1 (39.2-51.0) 19.7 (15.0-24.4) 40.3 (34.6-46.0) 2.7 (0.3-5.1) 18.0 (13.7-22.3) Multi-racial 71.6 (62.4-80.8) 18.7 (8.9-28.5) 46.6 (36.4-56.8) 29.7 (19.5-39.9) 49.1 (39.9-59.3) 6.8 (0.0-15.4) 26.8 (16.0-37.6) Smoking Never 69.2 (67.0-71.4) 12.1 (10.5-13.7) 47.5 (44.8-50.2) 18.6 (16.4-20.8) 34.4 (31.9-36.9) 2.6 (1.6-3.6) 19.2 (17.0-21.4) Status LT former 78.7 (76.9-80.5) 11.5 (9.9-13.1) 52.8 (50.3-55.3) 19.2 (17.2-21.2) 34.4 (32.0-36.8) 2.2 (1.4-3.0) 17.3 (15.5-19.1) RT former 85.9 (81.4-90.4) 12.1 (7.6-16.6) 40.8 (34.1-47.5) 27.8 (21.5-34.1) 49.2 (42.3-56.1) 3.9 (1.0-6.8) 14.5 (9.8-19.2) Current 88.1 (85.9-90.3) 13.1 (10.9-15.3) 45.1 (42.0-48.2) 26.1 (23.4-28.8) 49.0 (45.9-52.1) 3.4 (2.2-4.6) 16.4 (14.2-18.6) * Long-term: Ever smokers who quit more than a year ago at the time of survey. Recent-term: Ever smokers who quit within a year or less at the time of survey. doi: 10.1371/journal.pone.0079332.t005 Table 6. Susceptibility to Using E-Cigarettes in the Future . † ‡ Never smokers Long-term former smokers Recent former smokers Current smokers Overall sample (n=3,251) (n=3,256) (n=385) (n=2,882) (n=9,774) % (95% CI) % (95% CI) % (95% CI) % (95% CI) % (95% CI) Not susceptible 97.4 (96.6-98.2) 96.7 (95.9-97.5) 75.1 (69.6-80.6) 50.5 (47.4-53.6) 88.0 (87.1-88.9) All Susceptible 2.6 (1.8-3.4) 3.3 (2.5-4.1) 24.9 (19.4-30.4) 49.5 (46.4-52.6) 12.0 (11.1-12.9) All Susceptible by category Tried e-cigarettes 38.7 (25.4-52.0) 67.1 (56.1-78.1) 88.2 (80.7-95.6) 55.8 (51.5-60.1) 56.4 (52.6-60.2) Very likely 14.9 (7.3-22.5) 16.0 (6.8-25.2) 1.0 (0.0-2.4) 8.8 (6.6-11.0) 9.5 (7.5-11.5) Somewhat likely 46.4 (32.7-60.1) 16.9 (9.1-24.7) 10.8 (3.9-17.7) 35.4 (31.3-39.5) 34.1 (30.5-37.7) * Sample excludes those who reported current use of e-cigarettes. Smokers who quit more than a year ago at the time of survey. Smokers who quit within a year or less at the time of survey. doi: 10.1371/journal.pone.0079332.t006 clearly stoked interest in the products. Both articles included earned media is the intuitive appeal of the products: e- appealing pictures of e-cigarettes. The fact that “in-person cigarettes mimic regular cigarettes in so many ways that it conversation” was the second most frequently reported source seems to be, simply put, a clever invention. For example, as of information (ahead of “Internet”) in the present study also we were preparing the first draft of this paper, articles about e- suggests that many people find the products interesting cigarettes appeared in two highly regarded American enough to raise the topic with friends and colleagues. publications: National Geographic and Consumer Reports [62,63]. Neither article directly promoted e-cigarettes, but both PLOS ONE | www.plosone.org 8 October 2013 | Volume 8 | Issue 10 | e79332 Use and Perception of E-Cigarettes and Snus A limitation of the present study is that members of the users, current users of snus are more likely than non-users to KnowledgePanel sample may engage in more than one survey have made a quit attempt in the last 12 months. in a given year, which might lead to greater familiarity with The proportion of e-cigarette users who believe that e- certain topics. It is possible that the rate of self-reported cigarettes are safer than regular cigarettes is significantly awareness of e-cigarettes might have been inflated for that higher than snus users who believer snus is safer than reason, particularly because the survey described e-cigarettes cigarettes (50% vs. 11%). This perception may be incorrect, before asking if respondents had heard about them. However, but it may have contributed to the large increase in high rates of awareness have also been reported in other experimentation with e-cigarettes from 2010 to 2012, while surveys. For example, a study in England found that 62% and snus use has remained relatively constant. 79% of smokers were aware of e-cigarettes in 2010 and 2012, The contrast in American smokers’ interest in e-cigarettes respectively [5]. Consumer surveys in the U.S. also showed and snus is instructive in many ways. Snus has been an high awareness rate: In 2010 and 2011, awareness of e- established and popular tobacco product in Sweden for many cigarettes was 41% and 58%, respectively [37]. Although the decades. It came to the U.S. market six years before e- consumer survey in the U.S. was not based on a probability cigarettes [68]. It has the support of large U.S. tobacco sample of the entire population, it did show that awareness companies [27]. E-cigarettes, on the other hand, were first increased significantly. With these consumer survey data as a developed in China in 2003 and came to the U.S. market in reference, the high level of awareness found in the present 2007 [4]. Prior to the recent acquisition of the Blu e-cigarette study suggests that interest in e-cigarettes in the U.S. company by Lorillard, e-cigarettes were promoted mainly by continued to grow after 2011, to 75% in 2012 among the U.S small producers. Yet, the use of e-cigarette products has grown population as a whole (Table 5). from half that of snus in 2010 to twice that of snus by 2012. This increase in awareness is supported by the increase in One reason that more smokers are experimenting with e- the rate of ever use of e-cigarettes. The consumer survey cigarettes than with snus, however, appears to be the study, referenced above, reported that 3.3% of respondents in following: e-cigarettes appeal to both men and women while a web-based survey had ever used e-cigarettes in 2010, which snus appeals mainly to men. In fact, e-cigarettes appeal to increased to 6.2% in 2011 [37]. Another smaller but population- women more than men (Table 2). It is possible e-cigarettes are based survey in 2010 reported an ever use rate of 1.8% [64]. perceived as clean nicotine devices, which might appeal to The present study, which was population-based and conducted women more than men. The design and packaging of e- in March 2012, found 8.1% reported ever having used e- cigarettes and e-cigarette promotion that is specifically targeted cigarettes (Figure 1), 3 to 4.5 times higher the rates found in to women may also have contributed to this gender difference 2010. In contrast, ever use of snus has not increased from [69]. In any case, the fact that more women than men have 2010 to 2012. The ever use rates for snus from the two 2010 tried e-cigarettes deserves careful investigation. It is especially surveys cited were 5.4% and 5.1%, respectively [64,65]. The interesting since men are more likely to have heard about e- present study found 4.3% of respondents have ever used snus. cigarettes than women (Table 5). No other so-called potentially In other words, the ever use rate for snus was at least twice as reduced exposure product (PREP) has attracted more women high as that of e-cigarettes in 2010. By 2012, the rate of ever than men. use for e-cigarettes has jumped to be twice as high as that of The most striking contrast, perhaps, is between the adoption snus, and the rate of snus use has remained essentially of e-cigarettes and the adoption of another product that is very unchanged. similar to e-cigarettes. Premier, later called Eclipse, is almost Interestingly, this survey, based on a probability sample of exactly the same as an e-cigarette. It does not involve the U.S. population, found that most current users of e- combustion when smoked [70,71], it looks like a regular cigarettes use them on a non-daily basis. This differs from cigarette, and it lights up when smoked. However, it still uses previous studies that recruited subjects through websites, tobacco leaves. It heats the tobacco leaves to deliver nicotine whose samples are less likely to be representative of all e- to smokers. The product is reported to have cost the R.J. cigarette users [14,66,67]. For example, one online survey of e- Reynolds tobacco company about $1 billion U.S. dollars to cigarette users found 81% of them were daily users [7]. The develop and market test [72]. There was much discussion and present study did find, however, that e-cigarette users who are promotion when the product first came to market [71,73], but it recent former smokers are much more likely to be daily users never quite took off [73]. In contrast, e-cigarettes appear to than those who are still smoking regular cigarettes (Table 5). have tapped into the popular imagination quickly, initially This could be an indication that some of these recent quitters without the backing of any major tobacco company. are using e-cigarettes daily as a replacement for regular This study shows that nearly half of current adult smokers in cigarettes. the U.S. are susceptible to future use of e-cigarettes, and about Over 50% of those who have ever used e-cigarettes reported 25% of the recent former smokers are susceptible. In addition, trying to quit regular cigarettes as one reason they used e- 3.3% of long term former smokers and even 2.6% of adult cigarettes. This is supported by data that current users of e- never smokers are susceptible. While the rates for these latter cigarettes are indeed more likely than non-users to have made two groups are low, the size of these two groups is about 80% an attempt to quit regular cigarettes in the last 12 months of the adult U.S. population. It is not clear what proportion of preceding the survey. A smaller proportion of ever users of youth is susceptible to e-cigarette use. But the number of snus reported trying to quit regular cigarettes. Like e-cigarette potential e-cigarette users among adults is already very large. PLOS ONE | www.plosone.org 9 October 2013 | Volume 8 | Issue 10 | e79332 Use and Perception of E-Cigarettes and Snus All together, the rates in Table 6 translate to 29 million adults in cigarettes is still relatively low, and there has been no study the U.S. susceptible to e-cigarette use. suggesting that their coming to the market has led to any The popularity of e-cigarettes, if it continues to grow, creates detectable change in the quit attempt rate at the population a dilemma for the public health community. On the one hand, level. But more research on e-cigarettes or similar products e-cigarettes are a new kind of tobacco-based product that is that have a strong intuitive appeal may help in developing a completely unregulated. There are numerous brands currently conceptual model and corresponding policy to increase the on market, easily purchased over the Internet or even in gas population cessation rate. stations and convenience stores [74]. The ingredients of most The case of e-cigarettes and their rapid adoption, in brands are not reported. Safety data are lacking. Their efficacy conjunction with the lack of scientific data on safety and for helping smokers to quit regular cigarettes is not well efficacy, presents a difficult regulatory problem. It is imperative established. Their potential negative impact on tobacco control that the scientific community rise to the challenge. The usual norms is unknown, especially their potential to induce approach to research for any product intended to help smokers adolescent nonsmokers to take up tobacco-based products. quit using regular cigarettes proceeds from safety to efficacy. Meanwhile, many smokers believe e-cigarettes are safer than Such a process usually takes many years, and millions may be regular cigarettes. Many have used them with the hope that using e-cigarettes before that process is completed. Studies they would help them quit smoking regular cigarettes. A are needed to assess risks and benefits of these new products substantial proportion of smokers also find e-cigarettes for individual users more rapidly. Equally important, studies are cheaper than regular cigarettes (Table 4), which can contribute needed to identify factors that influence the population use to the popularity of the former. All of these data suggest that patterns and to determine how individual preference for various smokers in the U.S. are not waiting for a consensus view from products translates into benefit or harm on the population level. health authorities to decide if they should switch to e-cigarettes. Acknowledgements The results of the present study and those of previous studies suggest that e-cigarettes are likely to gain users in the next few We would like to thank David Cowling for his assistance in years regardless of the opinions of the scientific community. questionnaire design and statistical analysis. We would also The fact that e-cigarettes have quickly surpassed snus in like to thank Gary Tedeschi, Yue-Lin Zhuang, and Christopher perceptions related to safety and utility, and in actual use Anderson for their comments on earlier drafts of the among U.S. smokers suggests that some feature of e- manuscript. cigarettes must have tapped into smokers’ intuitive preferences. Whether these beliefs are correct or not, they Author Contributions could potentially be channeled into a productive public health campaign to increase the rate of current smokers trying to quit Conceived and designed the experiments: SHZ. Analyzed the cigarettes. Given that the population smoking cessation rate data: SHZ AG LY ML. Wrote the manuscript: SHZ AG SC ML has not improved in the last twenty years in the U.S., any LY LZ. Survey Design: SHZ SC LZ. measure that could increase the rate of smokers attempting to quit deserves consideration [75]. The rate of current use of e- References 1. 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