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Abstract
Background E-cigarette promotional posts with misleading nicotine warning labels on social media may lower adolescents’ risk perceptions of e-cigarettes. A between-subject experiment assessed effects of influencers’ e-cigarette promotional posts with different nicotine warning labels on adolescents’ e-cigarette harm perceptions, susceptibility to e-cigarette use and perceptions of influencer credibility.
Methods In 2022, adolescents (N=1864, Mage=17 (SD=0.6)) were randomised to view six images and videos featuring influencers promoting e-cigarettes in one of five experimental conditions: two conditions with a ‘tobacco-free nicotine’ warning label (placed on an e-cigarette in the post or at the top of the post), two conditions with the US Food and Drug Administration (FDA) nicotine warning label (on an e-cigarette in the post or at the top of the post (control)) and one no-label condition. Participants rated influencers’ credibility (eg, honesty). Harm perceptions of, and susceptibility to use, e-cigarettes were then assessed.
Results Participants who viewed posts with the FDA warning label at the top of the post perceived influencers as more honest, trustworthy and informed than in all the other conditions. E-cigarette never-users who viewed posts with a ‘tobacco-free nicotine’ warning label pictured on an e-cigarette (compared with the FDA label at the top of a post) were more likely to report susceptibility to e-cigarette use (adjusted OR 1.79, 95% CI 1.17 to 2.73).
Conclusions Alterations of the required nicotine warning labels can make them less effective in deterring e-cigarette use behaviour. Tobacco control authorities could increase enforcement of the FDA-required nicotine warning labels and harness influencers for antitobacco messaging.
- Nicotine
- Advertising and Promotion
- Electronic nicotine delivery devices
- Media
- Public policy
Data availability statement
Data supporting the conclusions of this manuscript will be made available by the authors, without undue reservation and in compliance with the IRB protocol, to any qualified researcher.
This is an open access article distributed in accordance with the Creative Commons Attribution Non Commercial (CC BY-NC 4.0) license, which permits others to distribute, remix, adapt, build upon this work non-commercially, and license their derivative works on different terms, provided the original work is properly cited, appropriate credit is given, any changes made indicated, and the use is non-commercial. See: http://creativecommons.org/licenses/by-nc/4.0/.
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WHAT IS ALREADY KNOWN ON THIS TOPIC
Research has shown that youth exposed to e-cigarette product imagery with ‘tobacco-free nicotine’ descriptors (compared with ‘nicotine’ descriptors) were more likely to report susceptibility to e-cigarette use and lowered harm or risk perceptions of e-cigarettes. Little is known about the effects of types and placement (location in a post) of nicotine warning labels, including a ‘tobacco-free nicotine’ label, in e-cigarette-related social media posts featuring influencers on e-cigarette harm perceptions and susceptibility to e-cigarette use among adolescents.
WHAT THIS STUDY ADDS
Adolescents who viewed influencer e-cigarette-related posts with ‘tobacco-free nicotine’ warning labels were less likely to report higher harm perceptions of e-cigarettes and more likely to report susceptibility to e-cigarette use compared with adolescents who viewed posts with the US Food and Drug Administration nicotine warning label with the required placement (top of the post). Alterations of the required nicotine warning labels can make the warning labels less effective in deterring e-cigarette use behaviour.
HOW THIS STUDY MIGHT AFFECT RESEARCH, PRACTICE OR POLICY
Tobacco control authorities may consider increasing enforcement of the required nicotine warning labels and harnessing influencers for antitobacco messaging.
Introduction
E-cigarette use among adolescents remains a global public health concern. Despite a decline in e-cigarette use among high school students in 2023, over 2 million (8%) of high school and middle school students in the USA reported past 30-day use of e-cigarette products.1 Among current users, 25% reported using e-cigarettes daily. In the UK,2 over 20% of adolescents tried e-cigarettes in 2023, up from 16% in 2022. E-cigarette use has also been growing among adolescents in Southeast Asia.3
Exposure to e-cigarette-related marketing content on social media increases the risk of e-cigarette use4–6 and use intentions,7 positive attitudes towards e-cigarettes, greater perceptions of e-cigarette use as normative and popular7 and lower perceived risks of e-cigarette use among adolescents.7 8 Particularly vulnerable groups of adolescents include e-cigarette never-users9 and social media users.4 Despite policies restricting tobacco advertising,10–12 social media platforms popular among youth (eg, Instagram, TikTok)13 host promotional e-cigarette content posted directly by tobacco brands or by influencers14–16 (ie, models, bloggers or brand ambassadors who partner with tobacco brands to post on their behalf). Brands, including e-cigarette companies, often use microinfluencers or nanoinfluencers (ie, influencers with fewer than 100 000 followers17 who occupy specific audience niches14) to post promotional content.18 These influencers may be perceived as more trusted sources compared with direct advertising from brands because of the greater perceived authenticity and relatability of the content.19 20 We recently identified engaging Instagram microinfluencers (n=55) from around the world (mostly the USA, the UK, France, Germany, Indonesia and Malaysia) who collaborated with over 600 e-cigarette brands.15 We also found that the prevalence of e-cigarette-related products promoted by microinfluencers has been growing on TikTok over the last several years.21 E-cigarette-related marketing content in prior research has often been defined broadly as ‘advertising’, with few studies analysing the effect of a specific source of marketing (eg, tobacco brand, celebrity22 or influencer)23 on youth perceptions and use patterns of e-cigarettes. With the proliferation of e-cigarette-related microinfluencer-driven content, more research is needed to analyse the effect of content posted by these influencers on adolescent perceptions and use patterns of e-cigarettes.
Microinfluencers promoting e-cigarettes use marketing tactics such as bright colours or youth-oriented design of e-cigarette products,24 stylisation of influencers to look young and fashionable,25 and promotion of e-cigarettes in a positive lifestyle context (eg, nature or active and healthy lifestyle).15 26–28 The incorporation of modified (altered) nicotine warning labels, or the absence or incorrect placement of the required nicotine warning label, in social media posts is another marketing tactic we observed in micro-influencer e-cigarette promotional content on Instagram (eg, online supplemental figure 1). The US Food and Drug Administration (FDA) requires that tobacco product advertisements (including advertisements with visual components,29 such as social media posts) use a warning label30–32 (‘This product contains nicotine. Nicotine is an addictive chemical’) placed at the upper portion of an ad, occupying at least 20% of the ad.29 The guideline prevents tobacco product manufacturers from ‘advertis(ing) or causing (tobacco products) to be advertised within the USA’ without the required warning label.29 When brands partner with influencers, they become a cause of tobacco marketing, even if the posts do not come from the brands’ own social media accounts.33 Influencers’ posts often lack or incorrectly place the warning label (eg, only on e-cigarette products promoted in a post, but not at the top of the post).
Supplemental material
Some influencers’ posts use an altered version of this warning label (placed either on an e-cigarette product or at the top of a post), that is, ‘This product contains Tobacco-Free Nicotine. Nicotine is an addictive chemical.’ This ‘tobacco-free nicotine’ label represents a marketing claim used to promote synthetic nicotine e-cigarettes (ie, containing nicotine not derived from a tobacco leaf) as ‘cleaner’ and ‘higher quality’ compared with regular e-cigarettes34 or tobacco-derived nicotine. Adolescents35 and young adults36 exposed to e-cigarette imagery with ‘tobacco-free nicotine’ descriptors (compared with ‘nicotine’ descriptors) were more likely to report susceptibility to e-cigarette use36 and lowered harm36 or risk perceptions35 of e-cigarettes. However, currently, there is no evidence that products containing synthetic nicotine have different health effects or are less addictive than products containing tobacco-derived nicotine.37 E-cigarette brands advertise synthetic nicotine products online36 and marketing research38 projects a growth direction for the synthetic nicotine market from 2024 to 2030. Yet, little is known about the effects of the ‘tobacco-free nicotine’ warning labels in e-cigarette-related social media marketing content posted by microinfluencers on adolescent e-cigarette harm perceptions and susceptibility to e-cigarette use.
This study used an experimental design to examine the effects of types and placements of the FDA-required and altered (ie, ‘tobacco-free nicotine’) warning labels on e-cigarette harm perceptions, susceptibility to e-cigarette use and perceptions of influencer credibility among adolescents. We hypothesised that adolescents would have lower harm perceptions of e-cigarettes (H1) and higher odds of susceptibility to e-cigarette use (H2) if they viewed posts with a ‘tobacco-free nicotine’ warning label placed on an e-cigarette in the post or at the top of the post (vs the FDA nicotine warning label placed at the top of the post as required) in promotional e-cigarette-related images and videos posted by microinfluencers on Instagram or TikTok. We also explored how these different warning labels may affect perceptions of the influencers, and how perceptions of the influencers may affect e-cigarette harm perceptions and susceptibility to e-cigarette use, based on two theoretical frameworks: the elaboration likelihood model (ELM)39 and the prototype willingness model (PWM).40 Based on the ELM, perceptions of a spokesperson can affect the persuasiveness of an advertisement.23 39 For example, if an influencer is perceived as trustworthy, their message will be more persuasive. Based on the PWM, adolescents could emulate risky health behaviour (eg, e-cigarette use) of a prototype (eg, an influencer) if this prototype is perceived positively.
Materials and methods
Participants and procedures
We used the Trends in Tobacco Use Survey41 run by the University of Southern California Tobacco Center of Regulatory Science to conduct this study. The experiment was conducted in 2022–2023 among 12th-grade participants from 10 high schools in the socioeconomically and racially diverse Los Angeles, California metropolitan area. Of the 2298 eligible participants (ie, students with both parental consent and youth assent), 1910 (83%) completed the 20 min online survey, programmed in REDCap, on their classroom Chromebooks during class time.
Sample for the experimental stimuli
The experimental stimuli for the study were created from the publicly available Instagram and TikTok posts of existing Instagram microinfluencers with public accounts (n=55) identified in prior research.15 These microinfluencers regularly (at least once a month) post promotional e-cigarette content. All of these microinfluencers had previously disclosed that they were sponsored by e-cigarette companies.15 Eight out of 55 profiles—4 males and 4 females based in the USA (as indicated in their Instagram profile descriptions)—were initially selected for the stimuli, then altered for each experimental condition, described below.
Experimental stimuli manipulation
To ensure that the experimental stimuli across conditions match closely and differ only by the experimental condition, we used Adobe Premiere and Adobe Photoshop editing software to alter some of the selected posts (eg, replacing or removing a warning label) while making such alteration imperceptible to viewers. Before conducting the experiments, 10 undergraduate students reviewed the stimuli and assessed them (0–10 scale) by answering stimuli validation questions about the visibility (readability) of the warning labels, perceived gender and perceived age of influencers (table 1). To ensure that the stimuli were homogeneous, six out of eight reviewed influencer profiles with the highest rating agreement and highest rating scores (≥8) were selected for the experiments. Two profiles received lower scores and were excluded because their faces on the imagery were slightly blurred.
Stimuli validation and experiment outcome measures
Experimental design
Each participant viewed six posts (three Instagram images and three 10 second long Instagram or TikTok videos) assigned using simple randomisation. The posts featured six influencers (three males and three females) promoting flavoured disposable e-cigarette products. (Flavoured disposable products are prevalent in e-cigarette-related influencer marketing on TikTok9 and are the most widely used e-cigarette products by youth).1 E-cigarette brand names were not shown. The posts differ across five experimental conditions: a ‘tobacco-free nicotine’ warning label (1) or the FDA-required nicotine warning label (2) placed on an e-cigarette product featured in the post; no warning label (3); a ‘tobacco-free nicotine’ warning label (4) or the FDA-required nicotine warning label (5, control) placed at the top of a post (figure 1). The control condition reflects the FDA’s requirements.
Types of nicotine warning labels in influencer e-cigarette-related social media posts used in the experimental stimuli among adolescents. Posts featured five experimental conditions (as annotated): ‘tobacco-free nicotine’ warning label placed on the e-cigarette product promoted in the post (1); the FDA-required nicotine warning label placed on the e-cigarette product promoted in the post (2); no warning label (3); ‘tobacco-free nicotine’ warning label placed at the top of the post (4); the FDA-required nicotine warning label placed at the top of the post (5, control). Publicly available photographs were sourced from the public Instagram account of an influencer Drewdirps in July 2022 (https://www.instagram.com/drewdirps/). FDA, Food and Drug Administration.
Statistical analysis
Analytical samples
Harm perceptions of e-cigarettes and perceptions of influencer credibility were assessed among all adolescents who completed the experiment (N=1864). Susceptibility to e-cigarette use was assessed among never-users of e-cigarettes (n=1379). Since prior research showed9 42 that social media users are more likely than social media non-users to be exposed to e-cigarette content, we also assessed harm perceptions (n=1350) and susceptibility to e-cigarette use (n=1001) among adolescents who reported using Instagram and/or TikTok. These subgroups of interest were determined a priori. (Sample sizes for all the experimental conditions are reported in online supplemental figure 2). Based on the post hoc power analysis calculated in G*Power V.3.1, we had over 95% power to detect an OR of 1.6 with the sample size of 1001 to assess susceptibility to e-cigarette use and to detect an OR of 1.04 (or 0.96) with the sample size of 1350 to assess harm perceptions of e-cigarettes.
Supplemental material
Outcome measures
Harm perceptions of e-cigarettes (H1)
We assessed harm perceptions of e-cigarettes after participants viewed all posts with the two-item scale (table 1) adapted from the Population Assessment of Tobacco and Health (PATH).43 The two items were combined into one variable (α=0.86).44
Susceptibility to e-cigarette use (H2)
We assessed the susceptibility to e-cigarette use after participants viewed all posts with the four-item scale (table 1) adapted from PATH. The four items were combined into one variable (α=0.93). Consistent with prior research,45 the susceptibility to e-cigarette use variable was collapsed into dichotomised responses: responding ‘definitely not’ to all items vs responding ‘definitely yes’, ‘probably yes’ or ‘probably not’ to one or more items.
Perceptions of influencer credibility (exploratory hypothesis)
Perceptions of influencer credibility: honesty, trustworthiness, subject knowledge, intelligence, attractiveness and popularity (using a scale validated in prior research)23 46 were assessed on a 0–100 scale after participants viewed each influencer’s post (table 1).
Statistical analysis
We used quasi-Poisson regressions to assess the effects of experimental conditions on harm perceptions of e-cigarettes. We used quasi-binomial logistic regressions to assess the effects of experimental conditions on susceptibility to e-cigarette use.
All regression models used fixed effects and clustered SEs to account for the clustering of participants within 10 schools. To increase power, multivariable regression models to assess harm perceptions of e-cigarettes were adjusted for sociodemographic characteristics (table 2) and use of e-cigarettes, other tobacco products and marijuana. Multivariable regression models to assess susceptibility to e-cigarette use were adjusted for the same covariates except for e-cigarette use (since susceptibility was measured among never-users of e-cigarettes). The choice of covariates was guided by prior research since these covariates were expected to be associated with the outcome variables.23 The FDA-required nicotine warning label placed at the top of a post was chosen as a control condition as being the official and fully complaint with the FDA requirements. Adjusted ORs (AORs) with 95% CIs were reported (table 3) with statistical significance set at p<0.05 (two tailed). Benjamini-Hochberg multiple testing corrections were applied to control for the false discovery rate at 0.05. (Additional analyses included examination of warning label condition X perceived influencer credibility interactions and examination of the effects of warning label condition on harm perceptions only among ever-users of e-cigarettes, N=349).
Characteristics of adolescents who completed the experiment (N=1864)
Effects of different types of nicotine warning labels on harm perceptions and susceptibility to e-cigarette use among adolescents
We also applied one-way analysis of variance (ANOVA) to compare mean influencer credibility perception scores across conditions and Tukey’s honest significant difference post hoc test to assess differences between pairs of group means. Each perceived credibility trait (eg, honesty) was evaluated separately for each influencer. Scores for the six influencers the participants viewed were averaged per each trait, yielding one score per trait (eg, perceived honesty) for each participant.
Finally, using Welch two sample t-tests, we compared mean influencer credibility perceptions scores (regardless of the warning label conditions) between participants with lower harm perceptions of e-cigarettes (at or below the median harm perceptions value) and participants with higher harm perceptions of e-cigarettes (above the median harm perceptions value), as well as between participants susceptible and not susceptible to e-cigarette use. All statistical analyses were conducted using R software (V.4.2.2).
Results
Adolescents (N=1864) were Mage=17 (SD=0.6); 55% female, 55% Hispanic. Among the participants, 23% reported ever-using e-cigarettes in their lifetime. Among adolescents who used Instagram and/or TikTok monthly or weekly, 24% reported frequent exposure (weekly, daily or several times per day) to tobacco-related content on these platforms. Among adolescents who used Instagram and/or TikTok several times per day, 35% reported frequent exposure to tobacco-related content on these platforms (table 2).
Harm perceptions of e-cigarettes (H1)
In the full sample (N=1864), adolescents who viewed posts with a ‘tobacco-free nicotine’ warning label placed at the top of a post were less likely to perceive e-cigarettes as harmful (AOR 0.96; 95% CI 0.93 to 0.98), compared with adolescents who viewed the FDA-required label and placement. Results were replicated in the subgroup of TikTok and/or Instagram users (N=1350; AOR 0.96; 95% CI 0.94 to 0.98; table 3).
Susceptibility to e-cigarette use (H2)
Among all e-cigarette never-users (N=1379), there were no statistically significant differences in susceptibility to e-cigarette use across the experimental conditions. Among never-users of e-cigarettes who used TikTok and/or Instagram (N=1001), adolescents who viewed posts with a ‘tobacco-free nicotine’ warning label placed on an e-cigarette were more likely to be susceptible to e-cigarette use (AOR 1.79; 95% CI 1.17 to 2.73) than those who viewed posts with the FDA-required label and placement (table 3). No significant warning label X perceived influencer credibility interactions emerged for either outcome. Harm perceptions among e-cigarette ever-users did not significantly differ by warning label condition (p>0.05).
Perceptions of influencer credibility (exploratory hypothesis)
In the full sample (N=1864), perceived influencer credibility was highest among adolescents who saw the FDA-required warning label and placement, examining three traits separately: honesty (M=38.8, SD=24.2), trustworthiness (M=30.3, SD=22.3) and knowledge (being perceived as informed) (M=35.8, SD=23.5). Mean pairwise differences between the warning label conditions are shown in figure 2. Differences across conditions for the other influencer personality traits (intelligence, attractiveness and popularity) were not statistically significant and were not reported.
Mean differences in influencer perception scores for honesty, trustworthiness and knowledge (informed) personality traits measured in study 1 using one-way ANOVA and Tukey’s honest significant difference post hoc test to assess differences between pairs of group means. *p<0.05, **p<0.01, ***p<0.001. FDA (post top) and Tobacco Free (post top) represent respective nicotine warning labels placed at the top of a post. FDA and Tobacco Free represent respective nicotine warning labels placed on an e-cigarette product promoted in the post. ANOVA, analysis of variance; FDA, Food and Drug Administration.
Regardless of their assigned warning label condition, participants (n=591) with lower harm perceptions of e-cigarettes (ie, below the median value of the harm perception scales) perceived the influencers as more credible (averaged across honesty, trustworthiness and knowledge: M=36.6, SD=18.7), compared with participants (n=733) with higher harm perceptions of e-cigarettes (ie, at or above the median value of the harm perception scales), (M=26, SD=19.6; t=−9.9, p<0.001). Similarly, participants susceptible to e-cigarette use (n=332) perceived the influencers as more credible (M=37, SD=17.5) compared with the participants (n=962) non-susceptible to e-cigarette use (M=26.6, SD=20.2; t=−9, p<0.001). The mean influencer credibility perception scores when the FDA warning label was placed at the top of a post were still the highest among adolescents with higher and lower harm perceptions of e-cigarettes and among adolescents susceptible and non-susceptible to e-cigarette use.
Discussion
Using an experimental design, this study examined the effects of types and placements of the FDA-required and altered nicotine warning labels in microinfluencers’ posts promoting e-cigarettes on adolescent e-cigarette harm perceptions, susceptibility to e-cigarette use and perceptions of influencer credibility. Adolescents who viewed images and videos of influencers promoting e-cigarette products with a ‘tobacco-free nicotine’ warning label were less likely to perceive e-cigarettes as harmful, compared with adolescents who viewed posts of influencers promoting e-cigarette products with the FDA-required nicotine warning label. Among social media users who had never used e-cigarettes, those who viewed posts with a ‘tobacco-free nicotine’ warning label (vs the FDA-required label) were more likely to be susceptible to e-cigarette use. The findings are consistent with prior studies demonstrating that adolescents35 and young adults36 exposed to ‘tobacco-free nicotine’ (vs ‘nicotine’) descriptors or warning labels on e-cigarette imagery were more likely to be susceptible to e-cigarette use and perceived e-cigarettes as less harmful and risky. Adolescents might have interpreted a product labelled ‘tobacco-free nicotine’ as being free from considerable health risks.35
The findings suggest that adolescent perceptions of e-cigarettes were affected by their perceptions of warning labels and influencers. Regardless of the warning label condition, adolescents who had lower harm perceptions of e-cigarettes or were susceptible to e-cigarette use perceived influencers as more credible (more honest, trustworthy and knowledgeable) than adolescents with higher harm perceptions of e-cigarettes or non-susceptibility to e-cigarette use. This finding seems consistent with the PWM,40 which posits that adolescents are likely to emulate a health-risky behaviour (eg, e-cigarette use) of a prototype (eg, an influencer) if they perceive this prototype positively. Adolescents in the ‘tobacco-free nicotine’ warning label condition had lower harm perceptions and greater susceptibility to e-cigarette use than those who saw the FDA-required label, despite perceiving the influencers as less credible. This finding suggests that harm perceptions and susceptibility may be affected by nicotine warning labels independent of influencer perceptions. The tobacco-free warning label, which increased the odds of susceptibility to e-cigarette use, was only measured among never-users. Consistent with the ELM,39 never-users may have viewed e-cigarette promotions as not personally relevant, and therefore, processed the message through a low-effort peripheral route (as opposed to examining information thoroughly via a central route). With peripheral processing, the first part of the message (‘tobacco-free’) may have outweighed the remainder of the message. The brief duration of the exposure to the stimuli (three images and three 10 s videos) could have also contributed to peripheral processing for both ever-users and never-users of e-cigarettes (ie, all participants of the experiment).
The effect of the ‘tobacco-free nicotine’ warning label on susceptibility to e-cigarette use was only significant among adolescent never-users of e-cigarettes who reported using Instagram and/or TikTok use (90% of the participants). Familiarity with Instagram and TikTok interface and content (including tobacco related) may increase the persuasiveness of promotional messages. In this study, more adolescents reported seeing e-cigarette posts on Instagram or TikTok if they used these platforms frequently (eg, daily) than adolescents who used Instagram or TikTok less frequently (monthly or weekly). Prior research also shows that adolescent9 and young adult42 e-cigarette never-users may be more strongly influenced by e-cigarette marketing than e-cigarette users. Finally, longitudinal research shows that e-cigarette initiation42 may be driven more strongly by social cues (eg, social media posts) than is e-cigarette continuation, which can be affected by dependence symptoms and expectancies borne from personal experience.
Effects of the ‘tobacco-free’ warning label placement on susceptibility differed from effects on harm perceptions. The ‘tobacco-free’ warning label significantly increased odds of susceptibility only when the label was placed on the e-cigarette itself, while the ‘tobacco-free’ warning label significantly decreased perceived harm only when it was placed at the top of the post. Seeing the label applied directly to the product may have encouraged adolescents to link features of the message (eg, ‘tobacco-free nicotine’) to the product itself, thereby increasing susceptibility. Effect sizes of the two label placements on harm perceptions were similar, suggesting there may not be a meaningful difference between label placements on harm perceptions.
Findings have regulatory implications for the FDA. Adolescents exposed to e-cigarette-related posts with the fully compliant FDA nicotine warning label (placed at the top of a post and occupying about 20% of the post) were more likely to perceive e-cigarettes as harmful, less likely to be susceptible to e-cigarette use and perceived influencers as more credible. These findings are consistent with prior research.23 26 Since the required nicotine warning label has been used sporadically in e-cigarette-related posts on social media,30–32 tobacco control authorities may consider increasing enforcement of nicotine warning label requirements on social media. Automated, computer-vision surveillance techniques21 to monitor the prevalence of the required warning labels on social media could also be adopted. To increase compliance, the FDA could consider revising the warning label guideline by including the term ‘social media’ in the document. Similarly, the guideline could explicitly include sponsored posts by influencers in its definition of tobacco content requiring a warning label. Despite the FDA’s assertion of its authority over synthetic nicotine, marketing of synthetic nicotine products may still persist on social media in violation of the FDA regulation.47 Future research should assess social media influencer marketing of zero-nicotine e-juices or disposable e-cigarette products that may contain synthetic nicotine or nicotine analogues. Other countries that require similar nicotine warning labels (eg, UK,48 Canada49) may also consider increasing enforcement. Results also support public health efforts to harness influencers perceived as credible for antitobacco messaging and in health literacy campaigns about the harmful effects of e-cigarette use.40 50 51
Although most major social media platforms prohibit paid advertisements for tobacco products, only a few (ie, Facebook, Instagram and TikTok) explicitly prohibit influencers from promoting nicotine/tobacco products.12 23 According to the FDA and the Federal Trade Commission guidelines,52 53 if influencers have any material connection with a tobacco brand—meaning that they have been paid or given something of value to tout the product—such relationships need to be disclosed in their social media posts. These rules apply to posts made from the USA, and to posts made from abroad if it is reasonably foreseeable that the post will affect US consumers. Enforcement is inconsistent, and many influencers’ posts have ambiguous or absent disclosures of their partnerships with tobacco brands.15 Tobacco-related influencer marketing requires stronger regulations by social media and public health authorities. Such regulations do not violate freedom of speech. While some e-cigarette advertising is protected by the First Amendment of the US Constitution,54 the FDA considers the effects of advertising on youth when making decisions regarding marketing orders. For example, the FDA has stated support for companies’ intentions to use older models (over the age of 25–45) in marketing materials because young models might increase youth appeal of e-cigarettes.55 Federal agencies could go further by prohibiting e-cigarette brands from hiring influencers under a certain age,55–57 ban influencer advertising of e-cigarettes altogether or impose penalties for non-compliance with federal marketing regulations (eg, the use of required warning labels and sponsorship disclosures). Globally, international public health agencies should harness their efforts in pushing legislation to increase regulations of Tobacco Advertising, Promotion and Sponsorship, following guidelines of the WHO Framework Convention on Tobacco Control.58 Improved detection algorithms of tobacco content on social media is also needed.59 60
Limitations
Results may not generalise from California students to all US adolescents or adolescents in other countries. However, the ethnic diversity of the sample represents the projected future ethnic diversity of the USA.61 Despite the randomised experimental design, self-reported survey outcomes might be prone to social desirability bias. The measures were also assessed only at one point in time (vs multiple time points). While the experimental stimuli were created from actual Instagram and TikTok posts featuring microinfluencers promoting e-cigarette products, the survey did not use the actual Instagram or TikTok interface to simulate a real-life social media use experience. Finally, the study did not adjust for participants’ previous exposure to nicotine warning labels, which may influence its effectiveness.62
Conclusions
The study demonstrated that influencer marketing tactics, such as the use of the ‘tobacco-free nicotine’ warning label (vs the FDA-required warning label), in e-cigarette-related promotional posts on social media may contribute to decreased e-cigarette harm perceptions and to susceptibility to e-cigarette use among adolescents, especially among e-cigarette never-users who use social media. Future research may assess the effects of nicotine warning label placements in social media videos featuring influencers with different followings. Future research should also continue surveilling e-cigarette influencer marketing and investigating whether tobacco companies use influencers to introduce new or promote existing e-cigarette products in violation of premarket authorisation requirements. Our findings indicate the need for further regulation of influencer marketing globally, increasing enforcement of the FDA-required nicotine warning labels in the USA and increasing enforcement of the nicotine warning labels compliant with legislation in other countries. Results also support public health efforts to harness influencers for antitobacco messaging.
Data availability statement
Data supporting the conclusions of this manuscript will be made available by the authors, without undue reservation and in compliance with the IRB protocol, to any qualified researcher.
Ethics statements
Patient consent for publication
Ethics approval
This study involves human participants and the University of Southern California Institutional Review Board (UP-21-00352) approved all study procedures. Participants gave informed consent to participate in the study before taking part.
References
Supplementary materials
Supplementary Data
This web only file has been produced by the BMJ Publishing Group from an electronic file supplied by the author(s) and has not been edited for content.
Footnotes
X @JVassey
Contributors Concept and design: JV. Acquisition, analysis or interpretation of data: all authors. Draft of the manuscript: JV. Critical revision of the manuscript for important intellectual content: all authors. Statistical analysis: JV. Obtaining funding: JBU. Administrative, technical or material support: JV and JBU. Supervision: JBU and EAV. Guarantor: JV. All coauthors approved the final version.
Funding Research reported in this publication was supported by the NCI and FDA Center for Tobacco Products (CTP) Award (NCI/FDA grant #U54CA180905) with additional support from the National Institute on Drug Abuse (Grant #K01DA055073).
Disclaimer The funders had no role in study design; collection, analysis and interpretation of data; writing the report; and the decision to submit the report for publication. The content is solely the responsibility of the authors and does not necessarily represent the official views of the funders.
Competing interests None declared.
Provenance and peer review Not commissioned; externally peer reviewed.
Supplemental material This content has been supplied by the author(s). It has not been vetted by BMJ Publishing Group Limited (BMJ) and may not have been peer-reviewed. Any opinions or recommendations discussed are solely those of the author(s) and are not endorsed by BMJ. BMJ disclaims all liability and responsibility arising from any reliance placed on the content. Where the content includes any translated material, BMJ does not warrant the accuracy and reliability of the translations (including but not limited to local regulations, clinical guidelines, terminology, drug names and drug dosages), and is not responsible for any error and/or omissions arising from translation and adaptation or otherwise.