An electronic cigarette, also known as an e-cigarette, is a battery-powered device that provides inhaled doses of vaporized nicotine solution, which simulates the act of tobacco smoking and looks like a real cigarette. Recent years have witnessed tremendous growth in the e-cigarette marketplace. E-cigarettes were introduced to the Chinese market in 2004 and to the US market in 2007. Since 2008, US e-cigarette sales have been doubling every year, expected to reach $1 billion in 2013 [1, 2]. Although health benefits and possible adverse effects of e-cigarettes are still unsettled by the scientific community and there have been heated discussions as to regulatory approaches to e-cigarettes, it is undeniable that e-cigarettes are here to stay and could experience sustained growth as this line of product is quickly entering the public’s consciousness. A recent U.S. survey found that in 2011, 57.9% of the general public heard about e-cigarettes, rising dramatically from 40.9% in 2010 [3]. According to Google Trends, the volume of Web searches on “electronic cigarettes” has grown 50 times in the past 4 years [4]. Mobile applications dedicated to enabling social networking among e-cigarette consumers, referred to as “social smoking,” have been introduced (e.g., Blu Cigs Smart Pack). Many mainstream tobacco companies have acquired e-cigarette vendors. E-cigarette product promotional campaigns have been conducted on multiple mainstream marketing channels. Still a niche market representing a fraction of the tobacco product sales, this disruptive technology promises to reshape the tobacco industry and perhaps even pharmaceutical companies that market nicotine replacement products, prompting significant research interests and regulatory concerns.

Although the e-cigarette research literature is growing steadily, there are significant gaps to be filled. For consumers, healthcare providers, and regulators alike, a much better understanding of e-cigarettes’ health risks, efficacy for smoking reduction and cessation, and marketing efforts and messaging practice by e-cigarette vendors, is in critical demand. Although some e-cigarette companies market e-cigarette as a smoking cessation product, clinical studies have been inconclusive [5]. Some studies indicated that e-cigarette use led to substantially decreased cigarette consumption among smokers [6]. At the same time, there are concerns that e-cigarettes could become “bridge products” for use in places prohibiting smoking or starter products, attracting young people or former smokers to smoking [7]. In the absence of regulatory control, marketing of e-cigarette products in both mass and social media, has been prevalent, leading to confusion and raising concerns about the sustained effectiveness of tobacco control.

Founded in February 2005, YouTube allows billions of people to discover, watch and share originally-created videos. As the most popular video sharing website in the world, more than 1 billion unique users visit YouTube each month [8]. There are many publicly available videos that purposely promote tobacco use on YouTube [9]. Messages embedded in YouTube have the potential to influence tobacco-related attitudes, beliefs and behaviors. Social media websites like YouTube have recently become a critical platform for health surveillance [10] and social intelligence [11]. Taking YouTube as a data source, previous researchers have studied information on ‘smoking’ [12], smoking cessation [13], smoking imagery associated with cigarettes [14], smokeless tobacco [15] and little cigars [16]. Although there is a study which mined data on usage of e-cigarettes from YouTube videos [17], they didn’t examine the portrayal of e-cigarette content.

Despite the growing literature on the portrayal of tobacco on YouTube, there are no published studies to date that have systematically assessed e-cigarette content on YouTube. Given the potential that YouTube has to promote e-cigarette use through user-generated content or covert advertising, this study aims to gain a better understanding of what e-cigarette messages people are being exposed to on YouTube.

Regarding the producers behind videos, 79.5% (n = 147) of the “pro” e-cigarette videos were professionally made and 20.5% (n = 38) were made by amateurs. In terms of the demographic characteristics of the most prominent person in the 172 “pro” videos in which there were specific messengers, the gender of 63.4% (n = 109) of videos’ messenger was male, while the gender of 12.2% (n = 21) of videos’ messenger was female. Both male and female messengers existed in 23.3% (n = 40) of videos. Besides, 1.2% (n = 2) of videos’ messenger was a cartoon character, which may appealed to teenagers. In terms of the estimated age of the messengers, most of them were between 25 and 35 years old.

According to the demographic information available on YouTube containing information on three top gender and age groups for each video, the majority of the audience was from the “Male, 45–54 years” group. Specifically, in the 143 “pro” e-cigarette videos in which demographic information of viewers was available, “Male, 45–54 years” and “Male, 35–44 years” were the primary audience group of 92.3% (n = 132) and 90.2% (n = 129) videos, respectively. In terms of the female audience, “Female, 45–54 years” was the primary audience group of 23.1% (n = 33) of “pro” videos. Regarding the “neutral” e-cigarette videos, “Male, 35–44 years”, “Male, 45–54 years” and “Female, 45–54 years” were also the primary audience group. As a result, males and females of 45–54 years were the main audience of the sampled videos.

To the best of our knowledge, this is the first study to systematically document the quantity, portrayal and reach of e-cigarette videos on YouTube. First, we assessed the quantity of e-cigarette videos by investigating the availability of e-cigarette related messages. Through this study, we find that it is quite easy for people to get access to a larger number of e-cigarette videos. None of the sampled e-cigarette videos blocks youth viewing. Notably, males and females of 13–17 years were found among the main audience of two promotional videos on YouTube. Second, we assessed the portrayal of e-cigarette videos by investigating the overall attitude to e-cigarettes and documenting promotional and warning content for each video. This study found the vast majority of information on YouTube about e-cigarettes promoted their use and depicted the use of e-cigarettes as socially acceptable, which is agreement with previous studies of tobacco related videos on YouTube [9, 12–15, 17, 19–21]. The top 3 most prevalent genres of videos were advertisement videos produced by e-cigarette companies, user sharing videos produced by consumers and product review videos produced by vendors. Regarding the topics covered in these “pro” e-cigarette videos, most of them claimed that e-cigarette was healthier than real cigarettes and contained scenes showing that e-cigarette use was enjoyable or socially acceptable. In addition, direct Web links for e-cigarette purchase and brand mentions were very popular in these videos. On the contrary, only a tiny percent of videos mentioned facts that the efficacy of e-cigarettes for smoking cessation is not scientifically proven, some health experts are concerned about health risks associated with e-cigarette [22] and FDA is trying to regulate the production and marketing of e-cigarettes [23]. This study also found that “pro” e-cigarette videos were watched more frequently and rated much more favorably than “anti” ones. Obviously “pro” e-cigarette views were dominated in the discussion on YouTube, while “anti” e-cigarette voice was weak in the competition. Third, we assessed the reach of e-cigarette videos by investigating the number of views, comments, favorites, likes, dislikes and demographic information along with each video, which documented the countries in which the video was most frequently watched, age and gender of those most likely to watch the video. Through this study, we find males and females of 45–54 years were the main audience of the sampled videos and the viewership of these e-cigarette videos is global.

One of the most prevalent topics in the “pro” e-cigarette videos is a claim that e-cigarettes are safer and healthier alternatives to conventional cigarettes through delivering the experience of smoking while eliminating health risks associated with tobacco smoke. However, the health effects of inhaling nicotine vapor into lungs are still a subject of uncertainty and users are concerned about product safety and toxicity [24]. Currently, there is only very limited and conflicting data on toxicity, carcinogenicity and infectivity of the e-cigarette cartridges or vapors [22]. The regulatory agencies are also concerned about the quality control, since the performance of e-cigarettes is highly variable both between and within brands [25]. There is an urgent need for a better understanding of the short and long-term health effects associated with e-cigarette use.

Another highlighted topic in the “pro” e-cigarette videos, which is attractive to smokers wanting to quit smoking, is a claim that e-cigarettes can help them quit smoking. However, the WHO and FDA do not consider it to be a legitimate therapy for smokers trying to quit. Currently, their efficacy as a smoking cessation aid has yet to be adequately tested in appropriately designed trials. We do not know how effective e-cigarettes are as a smoking cessation aid and what impact does this product have on quitting. More broadly, we also need to investigate how e-cigarettes are being used (i.e., for dual use, temporary abstinence, long term as a tobacco substitute or part of a quit attempt, etc.) and by whom (i.e., covering age, socio-economic status, gender and ethnicity) [26]. Since what some e-cigarette marketers imply in the YouTube videos may mislead video viewers, further studies on the efficacy of e-cigarettes is in critical demand.

In addition to the safety and efficacy issues, public health advocates and health experts are also concerned that e-cigarettes have negative impacts on current efforts of tobacco control. First, like most of “pro” videos, e-cigarettes are presented as products like real cigarettes and their use was marketed as enjoyable or socially acceptable. To what extent, do these messages reinforce the idea of smoking? Specifically, we want to know what the impact is, if any, of e-cigarette use on the denormalisation of smoking [27]. Second, several videos say that consumers can use e-cigarettes everywhere, even in places where smoking real cigarettes is not allowed. This also raises concerns that it may undermine smoking-free legislation. Third, this study found that e-cigarette products usually come in multiple flavors (i.e., chocolate and strawberry), colors and fancy packaging and they have been endorsed by famous actors as well as fictional cartoon characters. These characteristics will appeal to adolescents and young adults. The above strategic questions are raised as e-cigarettes are becoming more and more popular. Researchers need to conduct more studies to help decision making in tobacco control.

This study found that “pro” e-cigarette information is dominated on YouTube and warning voice about the health risks associated with e-cigarette is weak. Notably, there were many disagreements along with the three “anti” e-cigarette videos. As the third most popular websites in the world, YouTube has the potential to reach and influence a huge audience. Our results suggest that it’s urgent to monitor e-cigarette videos posted on YouTube and information on other social media websites. Public health organizations should appropriately inform consumers of potential harms associated with e-cigarette use. At the same time, tobacco control advocates may also consider developing health messages to counter “pro” e-cigarette content on YouTube. In order to maximize the influence of health messages in public, in the future, it is worth studying which kind of message is the most attractive to people and whether there is any opinion leader among people.

Though currently there are no studies that examine how e-cigarette messages on YouTube may affect people’s perception, belief and behavior toward e-cigarettes, previous studies have showed that positive smoking information in movies and television can stimulate positive attitudes and beliefs as well as smoking behavior among adolescents and young adults [28]. In spite of the lack of published researches addressing whether if this association is any different, it is reasonable to anticipate a similar relationship between e-cigarette messages on YouTube and people’s perception, belief and behavior toward e-cigarettes. The presented study found that vast majority of information on YouTube about e-cigarettes promotes their use and depicts the use of e-cigarettes as socially acceptable, which can be treated as the first step toward understanding the impacts of e-cigarette YouTube videos on people.

Overall, our results demonstrate urgent need for further study of safety and efficiency of e-cigarette as tobacco cigarettes substitute. Since YouTube and other social media platforms have the ability to reach and influence a huge audience, public health community should also pay more attention on the potential impact of e-cigarette marketing on current efforts in tobacco control. Policy makers within the WHO MPOWER [29] framework also can be informed by the implications of our study. Not only careful monitoring and appropriate regulation is required, but also developing health campaigns on social media is critical for public health.

This study has several limitations. First, videos sampled in this study may differ from those sampled at a subsequent time, since YouTube videos have a rapidly changing nature. Second, we only use simple video statistics to describe the viewer engagement, instead of analyzing viewer comments along with each video in depth. Third, all the videos in the data sample were coded by only two trained reviewers and the reliability of the coding result may be affected. Last, the collected demographic data that YouTube provides may not be entirely accurate.

This study presents the first surveillance studies of the portrayal of e-cigarettes on YouTube. The results presented in our study highlight the extent of “pro” e-cigarette content on YouTube. It is critical to develop appropriate health campaigns to inform e-cigarette consumers of potential harms associated with e-cigarette use. Further research is needed to evaluate the influence of e-cigarette messages in YouTube videos on people.