The Knowledge, Attitude, Practice (KAP) model provides a framework for understanding the development of health-related behaviors through the processes of knowledge acquisition, attitude formation, and behavioral practices (10). This model has been extensively utilized in the context of vaping research, with various studies indicating that an increase in knowledge is associated with negative attitudes toward vaping and a greater likelihood of cessation (21–24). Furthermore, demographic variables such as gender (25, 26), older age (27, 28), lower educational attainment (29), and socioeconomic status (30) have been identified as predictors of vaping behaviors. Nevertheless, current literature has not sufficiently examined the underlying mechanisms that influence attitudes toward vaping.

A significant gap exists in understanding the inadequate awareness among vapers regarding the risks associated with e-cigarettes, which contributes to continued usage (31–34). For example, a lack of awareness about the potential harms and skepticism toward regulatory measures have impeded efforts to reduce vaping among Chinese middle school students (35). While previous research has focused on perceived risks and benefits of vaping, it has largely overlooked the perceptions surrounding policy enforcement.

This study aims to apply the KAP model to investigate youth vaping behavior, with an emphasis on the influence of social media on exposure to information about e-cigarettes (K), the perceptions of risks and benefits as well as policy enforcement (A), and the resultant behavioral practices (P). The research seeks to elucidate how social media shapes the psychological perceptions that affect vaping behaviors.

Perceived Policy Enforcement (PPE) refers to individuals' assessments of the effectiveness of policies (36) and plays a significant role in shaping tobacco-related behaviors through two main aspects: the strictness of policies and perceptions of enforcement. Research has shown that PPE is essential in decreasing youth smoking rates, particularly through school policies (37, 38) and state-level initiatives (39, 40). Studies indicate that adolescents' views on the enforcement of local regulations are inversely related to smoking prevalence, with anti-smoking norms acting as a mediating factor (41). Furthermore, the media plays a crucial role in enhancing PPE through the dissemination of information, as social media transforms public discussions and perceptions of enforcement (42–45). This phenomenon aligns with the KAP model, where media influences PPE, which in turn affects youth behaviors.

While existing research primarily focuses on traditional cigarettes, there are significant gaps in understanding the implications for e-cigarettes. Three key research priorities emerge: (1) Examining indirect mechanisms: Understanding how PPE mediates vaping behaviors could enhance the KAP model and inform policy modifications. (2) Investigating risk-benefit perceptions: Misunderstandings regarding the safety of e-cigarettes (46–50) may interact with PPE, necessitating further investigation. (3) Exploring the role of social media: Given its significance as a primary source of information for youth (51–53), the impact of social media on PPE and vaping requires empirical scrutiny.

Additionally, PPE influences broader health behaviors, with stronger perceptions of enforcement linked to healthier choices, including lower smoking rates (54, 55). In the context of vaping, PPE may discourage e-cigarette use by shaping public attitudes. Within the KAP framework, PPE acts as an attitudinal factor that connects knowledge to practices. While media significantly shapes PPE (56–60), the mediating variables between PPE and behaviors remain largely underexplored. Investigating these pathways could enhance the predictive capabilities of the KAP model and guide targeted interventions. This study aims to thoroughly explore the antecedent factors (such as social media) and subsequent mediators to clarify the role of PPE in youth vaping behaviors.

In modern information environments, social media plays a crucial role in engaging young people with content related to policies, influencing their views on enforcement through both active participation and algorithm-driven exposure (61). For example, platforms such as Weibo contribute to increasing public awareness of environmental policies (62). This research specifically investigates the context of e-cigarette regulation in China, aiming to fill existing gaps in understanding how different types of social media platforms affect perceptions of tobacco control enforcement. Previous studies have indicated that social media enhances the understanding of norms and perceptions regarding smoking (63, 64), yet they often overlook the unique dynamics and content attributes of specific platforms that contribute to these effects. This study will explore the variations among platforms and the characteristics of content that influence perceptions of enforcement within Chinese social media.

Additionally, social media messaging has a direct effect on health behaviors (18, 65–67, 69, 70). In the context of vaping, exposure to e-cigarette advertisements has been shown to significantly increase the likelihood of usage (71–74). However, prior research has not effectively identified which types of messages across different platforms exert the strongest influence on behaviors. This study seeks to examine the connections between different Chinese social media platforms and adolescent vaping in order to identify the most impactful characteristics of both the platforms and the messages, thereby enhancing the understanding of how digital media influences policy perceptions and behavioral outcomes.

Risk perception pertains to an individual's evaluation of health risks associated with specific behaviors, whereas benefit perception relates to an individual's recognition of the positive outcomes of those behaviors (75). Existing research indicates contrasting effects of these perceptions: risk perception tends to decrease engagement in unhealthy behaviors (76–78), while benefit perception tends to encourage such behaviors (79–81). The role of social media is critical, as it exacerbates these perceptions by presenting both positive and negative information regarding behaviors such as vaping (82–85). This research proposes that risk and benefit perceptions play distinct roles in youth vaping behaviors and highlights the significant impact of social media on shaping these perceptions.

Additionally, perceived policy enforcement influences evaluations of risk and benefit. Previous studies in public policy (86), climate initiatives (87), and health regulations (54) have established a link between the effectiveness of policies and risk perception. Likewise, a stronger perception of policy enforcement is associated with an increased perception of benefits from compliant behaviors, such as farmland protection (8).

In the context of vaping, more stringent enforcement of tobacco policies may diminish perceived benefits by indicating a higher level of harm, while simultaneously elevating risk perceptions. Within the framework of KAP model in China, this study introduces a mediation model (see Figure 1) that illustrates how social media exposure can directly and indirectly influence the likelihood of vaping among youth, with perceived policy enforcement, risk, and benefit perceptions serving as mediators. These mediators provide insight into how external factors translate into behavioral outcomes.

Drawing upon theoretical frameworks and existing research, as well as considering the context of perceptions regarding policy implementation and the social media usage in this study, we develop our research hypotheses and questions. Initially, concerning the direct association between PPE and youth vaping, we propose:

Secondly, we consider social media to be an essential source of information and propose a hypothesis regarding its influence on PPE and vaping behavior. In this context, we also develop two research questions that specifically examine the effects of social media on these two variables. They are:

The two variables previously mentioned not only exert independent effects on vaping behavior but also contribute to the formation of individuals' beliefs concerning electronic cigarettes. In this context, we investigate two critical beliefs—perceived benefits and perceived risks—and their impact on vaping behavior, thereby establishing pertinent research hypotheses. Furthermore, this research aims to establish hypotheses that investigate the direct relationship between these two beliefs and the perception of policy enforcement. In addition, we seek to explore potential mediating effects through specific research questions. Accordingly, we present the following research hypotheses and questions:

Based on a study investigating the prevalence of e-cigarette usage in China (68), we utilized G^*Power software to determine the necessary sample size. This computation was performed with thorough consideration to essential parameters, such as the proportion of e-cigarette users, the acceptable margin of error, and the probability of committing a Type I error, etc. Consequently, we concluded that the sample size should not be <478 participants. The sample must consist of individuals who are at least 18 years of age, as this is the legal age at which Chinese citizens are permitted to purchase e-cigarettes. The current study involved a sample of 724 participants, recruited through random sampling from a population of young individuals aged 18–30 in Guangdong Province, China. Recruitment took place via an online survey administered by Jishuyun Big Data, a data service provider, during the period from July to September 2024. The recruitment process utilized various methods, including telephone calls, emails, WeChat QR codes, and website invitations, while initially gathering basic demographic information to ensure the sample's representativeness and validity. Once the representative sample was established, participants were invited to anonymously access the survey website using their mobile devices and complete the questionnaire. Before completing the questionnaire, it was necessary for all participants to carefully read and sign an informed consent form. Following the submission of their responses, participants were provided with information regarding the purpose of the research. It is important to note that, due to privacy considerations, the study did not collect data concerning individuals' mental health or other substance use. Detailed demographic information about the sample is presented in the results section.

SPSS29.0 was used for data analysis. First, to investigate the direct impacts of four independent variables—namely, the frequency of exposure to social media concerning electronic cigarettes, the perceived enforcement of tobacco control policies, the perceived risks of vaping, and the perceived benefits of vaping—on the dependent variable, vaping behavior, a binary logistic regression analysis was carried out. Second, to assess the mediation models, we utilized Model 81 from the SPSS PROCESS macro (92) to produce bootstrapped confidence intervals (CIs). Third, to identify the specific social media platforms or combinations thereof that affected perceptions of tobacco control policy enforcement and vaping behavior, we conducted linear regression analyses for perceived enforcement of tobacco control policies and logistic regression analyses for vaping behavior, utilizing varying frequencies of social media exposure as independent variables.

This research examines the factors influencing vaping behavior among Chinese adolescents, focusing on the perceived enforcement of policies. Previous studies indicate that China is the world's largest consumer of tobacco products, and there is a concerning trend of decreasing age at which individuals initiate smoking, especially among the youth demographic, as highlighted by multiple sources (94–98). Also, the recent proliferation of social media has stimulated public discourse by disseminating and sharing various content, thereby altering public understanding and attitudes. This transformation, in turn, influences individuals' perceptions of policy enforcement (42–45). Therefore, a deeper understanding of how vaping behavior is influenced by social media and tobacco control policies, particularly the psychological mechanisms involved in this process, is crucial for effectively utilizing social media platforms and related policies to control smoking, especially in reducing youth vaping. The findings of this study reveal that daily exposure to vaping-related content on social media can have both direct and indirect effects on individuals' vaping behaviors. Specifically, the frequency of exposure to such content positively affects perceptions of the enforcement of Tobacco Control Policies. This perception, in turn, primes individuals' awareness of the risks and benefits associated with vaping, ultimately increasing or decreasing the likelihood of engaging in vaping behavior. Identifying this mediating pathway offers valuable insights into the psychological factors influencing youth vaping and introduces new approaches for health communication strategies aimed at intervening vaping behaviors. Additionally, framed within the KAP theory, the mediating model provides strong empirical support and theoretical contributions. The following sections will discuss the research results and their theoretical and practical implications in detail.

This study reveals that the perceived enforcement of Tobacco Control Policy does not have a significant direct effect on the likelihood of youth engaging in vaping behavior. Instead, it influences vaping through the mediation of perceived risks and perceived benefits. Specifically, the perception of effective enforcement of Tobacco Control Policy positively affects perceived risk, which in turn decreases the likelihood of vaping. Conversely, it also positively affects perceived benefits, thereby increasing the likelihood of vaping. This pathway is consistent with prior research indicating that perceptions of policy, including its effectiveness and enforcement strength, shape individuals' cognitions and attitudes, ultimately influencing their behaviors (99, 100). The interplay between perceived risk and perceived benefits, which should theoretically be opposite in terms of both causing and being caused by other variables, manifests in the pathways through which these perceptions influence vaping behavior. However, when influenced by the perceived enforcement of Tobacco Control Policy, both perceptions exhibit a positive impact. China's tobacco control policies may reflect a dual conceptualization distinguishing traditional and e-cigarettes, potentially shaping public perceptions and regulatory outcomes. When policies are perceived as strictly enforced, individuals associating regulations primarily with traditional cigarettes might view e-cigarettes as possible substitutes, which may amplify perceived benefits and possibly encourage vaping adoption. Conversely, activating policy concepts related to e-cigarettes could heighten risk perceptions, potentially discouraging their use (101, 102). This pattern may align with China's historical focus on regulating traditional cigarettes. Recent efforts to address e-cigarettes risks appear to integrate vaping governance into existing tobacco frameworks rather than establishing separate policies.

From the perspective of psychological mechanisms, tobacco control policies may generate dual perceptions of e-cigarettes: awareness of health risks and belief in their substitution benefits for conventional cigarettes. This duality could create cognitive dissonance as users navigate conflicting cognitions—risk vs. benefit. When an individual's actions are at odds with both the risk perception emphasized by policies (e.g., health hazards) and the perception of e-cigarettes as beneficial (e.g., as a tool for quitting traditional cigarettes), psychological tension may arise from the inability to reconcile these conflicting beliefs. This dissonance may motivate individuals to resolve the tension through various strategies, such as altering their behavior (e.g., quitting e-cigarettes or exclusively using e-cigarettes without reverting to traditional cigarettes), selectively reinforcing one side of the cognition (e.g., emphasizing harm reduction or amplifying risks), or seeking external justification from policy authority (e.g., interpreting the policy as only requiring the cessation of traditional cigarettes, thereby rendering individual e-cigarette use permissible and rational). These strategies aim to reconcile contradictions and regain cognitive consonance. While this framework proposes explanatory psychological mechanisms, their operation along these pathways remains subject to empirical validation.

Based on the findings of this study, two practical implications emerge. First, it is crucial to strengthen the enforcement of tobacco control policies to enhance the perceived authority of these regulations concerning e-cigarettes, thereby reducing unhealthy behaviors. Second, policies should explicitly delineate the risks associated with electronic cigarettes and the relevant regulatory provisions, with the objective of maximizing public awareness regarding the potential dangers posed by e-cigarettes. It is essential to recognize that tobacco control is a comprehensive concept rather than one specifically targeting traditional cigarettes or e-cigarettes only; thus, when mention tobacco control invoke two distinct concepts—e-cigarettes and traditional cigarettes—which differentially influence risk and benefit perceptions.

This study also examined the impact of social media exposure on vaping behavior. The results suggest that exposure to e-cigarette-related content on social media significantly enhances vaping behavior. Additionally, this exposure indirectly influences vaping through perceived enforcement of Tobacco Control Policies and the perception of risks and benefits associated with vaping. Within the framework of the KAP model, social media exposure is categorized as knowledge, which subsequently increases the likelihood of adopting specific practices. In the context of vaping, a higher frequency of exposure to e-cigarette information or advertisements on social media correlates with an increased likelihood of vaping. Typically, individuals who frequently encounter such social media content—whether through active searches, passive algorithmic feeds, or casual scanning—demonstrate heightened attention to e-cigarettes, thereby increasing their propensity to engage in vaping behavior. This direct relationship is consistent with findings from prior research (71, 103–105).

The selective exposure theory suggests that individuals shape their information environment based on their existing behaviors, which may create a reverse causal relationship that contradicts this paper's argument. For instance, young people who are inclined to use e-cigarettes might actively seek out related content on social media. This self-selection means that media exposure may result from their behavioral tendencies rather than cause them. Furthermore, this active engagement may create a reinforcing loop: individuals may strengthen their perceived rationality of the behavior through information filtering (e.g., favoring pro-e-cigarette content), social validation (e.g., interacting with like-minded users), or emotional resonance (e.g., associating e-cigarettes with being 'cool' or 'fashionable'). Thus, a loop may form where behavioral inclination leads to media exposure, which in turn reinforces that behavior. Additionally, there may be a bidirectional dynamic relationship between media exposure and behavior: initial behavioral tendencies might drive selective exposure, while the encountered information (e.g., product glorification, peer modeling) might reduce perceived behavioral costs (e.g., others' use is harmless), potentially driving the implementation or continuation of the behavior. This complex interplay requires further validation through longitudinal data or instrumental variable analysis to potentially distinguish the antecedents and consequences of media exposure.

Moreover, young adults exposed to e-cigarette-related information on social media tend to perceive a stronger enforcement of Tobacco Control Policies. This is particularly evident in the context of China, where direct e-cigarette advertisements are prohibited on social media platforms. Users often modify keywords associated with e-cigarettes to present advertising content more subtly. Such exposure to relatively discreet information fosters the perception that regulatory policies are actively governing e-cigarette use, thus enhancing their sense of enforcement. Additionally, much of the content available on social media regarding e-cigarettes comprises health-related information and discussions of tobacco control policies. Engagement with this type of content increases users' awareness of the harmful effects of e-cigarettes and their understanding of current policy measures, thereby reinforcing their perception of enforcement. Through this process, as previously noted, social media exposure shapes young adults' perceptions of risks and benefits, subsequently influencing their vaping behavior. This mediating effect elucidates a mechanism by which policy enforcement relates to social media's role in shaping vaping behavior, offering new avenues for intervention strategies targeting vaping through social media platforms.

Our research has uncovered various direct and indirect pathways through which different types of social media information impact individuals' vaping behaviors. Specifically, exposure to e-cigarette-related content on two distinct Chinese social media platforms—WeChat Video Channels (negative impact) and Baidu Tieba (positive impact)—has been found to significantly influence the vaping behaviors of young individuals, albeit in contrasting ways. Analysis of the content on these platforms indicates that: (1) WeChat Video Channels primarily disseminate health education and policy-related information regarding the dangers of e-cigarettes, devoid of any advertising. Consequently, increased exposure to such content tends to diminish the likelihood of vaping; (2) In contrast, Baidu Tieba is characterized by a higher prevalence of advertising-oriented information about e-cigarettes, often presented in a manner that lacks health education. Users frequently employ ambiguous terminology to promote e-cigarettes in order to circumvent online censorship, which, in turn, heightens the likelihood of vaping among those frequently exposed to such content. Furthermore, the study reveals that greater exposure to e-cigarette-related information across four accessible social media platforms—WeChat Moments, REDNote, Baidu Tieba, and various international social media outside China—reinforces young people's perception of the enforcement of Tobacco Control Policies in China. Notably, platforms such as Baidu Tieba and REDNote contain a substantial number of e-cigarette advertisements, often rephrased with ambiguous keywords to evade censorship. On the one hand, exposure to these rephrased messages primes users' understanding of regulatory frameworks, heightening their perception of policy enforcement. On the other hand, the presence of e-cigarette advertisements, particularly those from international social media outside China that utilize more explicit content, may further amplify users' perception of strong policy enforcement when they encounter such information across different platforms. We contend that numerous Chinese social media platforms continue to inadequately regulate this obfuscated and homophonic content, thereby increasing the likelihood of exposure to these advertisements among young people, which subsequently influences their vaping behaviors through both direct and indirect psychological mechanisms. Therefore, the timely identification and warning of harmful health information on social media, along with the enhancement of information regulation, represent effective administrative strategies for mitigating vaping behaviors.

This study investigates various critical factors that influence vaping behavior, uncovering the fundamental mechanisms involved, which carry significant theoretical implications. Initially, we enhance the KAP model related to youth vaping, specifically exploring how perceptions regarding the enforcement of tobacco control policies impact individuals' views on associated risks and benefits. This enhancement broadens the pathways linked to attitudes, thereby offering new frameworks for understanding vaping behavior. Second, the study underscores the confusion that arises when applying conjoint behavioral concepts, such as tobacco control, to distinct behaviors such as e-cigarette use vs. traditional cigarette smoking. This confusion may result in different outcomes in individual decision-making processes due to the activation of various behavioral constructs. In terms of agenda-setting in health policy communication, the precise definition of concepts and the priming mechanisms are vital for influencing individuals' cognition, attitudes, and behaviors at a micro level.

This study presents practical implications in two significant dimensions. First, tobacco control policies must not only raise public awareness through a well-rounded conceptual framework but also involve targeted advocacy efforts tailored to specific behaviors and contextual factors. In the case of China, the existing tobacco control policies demonstrate extensive reach and comprehensive regulation; however, there is a pressing need to enhance enforcement mechanisms. This enhancement is essential for effectively shaping public perceptions regarding the risks associated with e-cigarette use and for mitigating vaping behaviors. Second, given that social media platforms serve as vital sources of information for young individuals, it is crucial to manage health-related information with precision. This includes minimizing ambiguity and coded messaging and improving the scope and depth of health science information dissemination. Such strategies are intended to enhance public risk perception and rectify the widespread misconception that e-cigarettes pose no harm to human health.