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  and FDA is trying to regulate the production and marketing of e-cigarettes . 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 . Currently, there is only very limited and conflicting data on toxicity, carcinogenicity and infectivity of the e-cigarette cartridges or vapors . The regulatory agencies are also concerned about the quality control, since the performance of e-cigarettes is highly variable both between and within brands . 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) . 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 . 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 . 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  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.