The prevalence of smoking has decreased in some countries during the past 30 years; however, the overall number of smokers worldwide has increased from 0.99 billion in 1990 to 1.14 billion in 2019 due to population growth (1). As a result, tobacco smoking continues to pose a significant health challenge, leading to substantial morbidity and mortality, as well as contributing to negative societal consequences, such as increased healthcare costs (1, 2). In 2019, tobacco smoking was responsible for an estimated 8 million deaths globally and was the leading cause of death and disability among men (1). In Italy, the prevalence of tobacco smoking remains high, at approximately 20.5% in 2023, despite declining from the recent peaks of 24.2% in 2022 and 22.0% in 2019 (3, 4).

The current tobacco control measures fall short and are unlikely to lead to the achievement of the World Health Organization (WHO) objective of a 30% reduction in the prevalence of smoking by 2030 (5). A fundamental change is needed to promote substantial progress in this area.

Tobacco harm reduction is commonly defined as a public health strategy that seeks to prevent or reduce the damage caused by the toxins generated by tobacco combustion for people who wish to continue smoking or who are unable to quit, rather than aiming at complete abstinence from nicotine use (6–8). The use of tobacco results in nicotine addiction and, therefore, harm reduction strategies have the potential to improve outcomes in those who do not give up tobacco smoking (6, 9, 10).

Over the past decade, smoke-free alternatives to tobacco, including electronic cigarettes, heated tobacco devices and orally administered tobacco- or nicotine-based products have become popular, yet controversial substitutes for tobacco cigarettes among smokers worldwide (11–17). Compared with conventional cigarettes, smoke-free alternatives offer a substantial reduction in exposure to toxic chemicals; for this reason, these alternatives can be used to reduce the harm caused by cigarette smoke and as aids for smoking cessation (6, 7, 18–22). One review found that the prevalence of tobacco smoking is lower, particularly among young people, in countries that have higher rates of adoption of smoke-free tobacco alternatives, such as the United Kingdom, Sweden, Norway, New Zealand and Japan, compared with other countries (23).

Despite their growing use, the role of smoke-free alternatives for tobacco harm reduction remains a subject of debate. The scientific and medical communities have addressed the overall potential benefit and harm of these alternatives, with divergent opinions on their efficacy, safety and societal implications (24–28). This controversy underscores the need for consensus on the role of smoke-free alternatives in reducing the burden caused by tobacco smoking. Given this context, the objective of this study was to formulate a consensus on the role of smoke-free products in reducing the harm caused by tobacco.

In total, 38 statements were developed across the three areas of interest: 11 statements in Area 1 (harm from tobacco smoking and strategies for harm reduction), 19 in Area 2 (smoke-free alternatives to cigarettes) and eight in Area 3 (anti-smoking legislation).

During the first round of voting, consensus was reached regarding 17 statements, while members of the Expert Panel did not reach consensus regarding 19 statements ( Supplementary Figure 1 ). In addition, opinions diverged on two statements to such an extent that consensus was considered unlikely. These statements were withdrawn from the second round of voting. Following the first round of voting, members of the Scientific Committee discussed and revised the 19 statements on which respondents did not reach consensus.

During the second round of voting, consensus was reached regarding seven additional statements ( Supplementary Figure 1 ). Members of the Expert Panel did not reach consensus regarding 12 statements.

The final version of the statements is presented in Table 1 . In Area 1, consensus was reached for eight statements (Statements 1 and 3–9). In Area 2, consensus was reached on 10 statements (Statements 19–21, 23–26 and 28–30). In Area 3, the panel reached a consensus on six statements (Statements 31–34, 37 and 38).

The present Delphi study facilitated rigorous discussion and consensus-building among a panel of experts in various therapeutic areas on the issue of using smoke-free alternatives to cigarettes for tobacco harm reduction in Italy. Profound differences of opinion are known to exist within the medical profession on the question of tobacco harm reduction, as confirmed during this study. This highlights the need for increased efforts to promote dialogue and consensus-building. The Delphi method is a valuable tool for navigating controversies and uncertainties in various scientific fields by providing a structured approach for collecting and synthesizing expert opinions. Importantly, to our knowledge, this is the first Delphi consensus statement to examine the role of smoke-free products in reducing the harm caused by tobacco. The use of the Delphi method in the present study facilitated the delineation of common ground and spotlighted areas of divergence, predominantly those related to tobacco harm reduction. Given the controversial nature of this field, it was not surprising that a clear consensus could not be reached on several statements.

While certain key statements did not achieve consensus in the Delphi process, this disagreement should be viewed as an interpretive opportunity rather than a limitation. Considering the lack of consensus in the broader context of the entire study, it becomes clear that some discrepancies may be due to misinterpretations or incorrect wording of specific questions. This highlights the importance of clear question framing in future studies. At the same time, the existence of disagreements reflects the complexity of the issue and underscores the value of the Delphi method in fostering nuanced discussions and navigating controversies.

The lack of consensus on statement 12 is balanced by the consensus reached in statement 19. This highlights the importance of long-term studies to confirm the reduction of harm with smoke-free alternatives, despite the significant reduction in exposure to toxicants.

The lack of consensus on statement 13 can be attributed to the wording of the question. It appears that some panelists (23%) may have interpreted “exclusive use” as the only option, without any cessation attempts (e.g., NRT use), rather than a complete transition to smoke-free alternatives without dual use with combustible tobacco products. This indicates that clearer formulation of questions is crucial to avoid potential misinterpretations.

The lack of consensus on statement 14 likely stems from an incorrect formulation of the question regarding the FDA statement. The FDA used “modified levels” instead of “decreased levels” of Harmful and Potentially Harmful Constituents (HPHC). This suggests that some panelists highlighted this oversight rather than disagreeing with the FDA’s opinion.

The lack of consensus on statements 35 and 36 is in contrast with the consensus reached for statements 33 and 34. This inconsistency, where the consensus and lack of consensus reached for those statements are in stark contrast to each other, has no explanation other than some panelists could have misinterpreted the relevant questions. It should be noted that the lack of consensus is the result of the peculiar wording used in statements 35 and 36 (where, at any rate, there was an average consensus of 80%) as they referred to “all smokers” and not to “adult smokers who would otherwise continue smoking.” When comparing such a result to the one of statement 21 (100% consensus), the Expert Panel did agree about making smoke-free alternatives accessible to adult smokers who would otherwise continue smoking (with information to enable informed decision-making). However, the take-home message from the cumulative interpretation of such statements is that not all tobacco products have the same risk profile (continuum of the risk concept) and that more restrictive regulations should be applied to products which are potentially more damaging.

The lack of consensus on statements 10 and 11 is apparently in contrast with the consensus reached for statement 20.

On one hand, evidence from recent studies by Qureshi and colleagues (37), Rose and colleagues (38), La Rosa and colleagues (39), and Ansari and colleagues (40) highlights the benefits of smoke-free alternatives in reducing exposure to toxicants and improving health outcomes. On the other hand, findings by several authors underscore unresolved risks, such as the impact of smoke-free products on small airway function (41), tumor metastasis (42), hypertension (43) and cardiorespiratory fitness (44). This duality underscores the contentious nature of tobacco harm reduction and the need for ongoing research and debate to guide evidence-based policies.

However, when interpreted cumulatively, the Panel consensus was clear: both the Harm Reduction approach and assisting adult smokers who would otherwise continue smoking to transition from cigarettes to less damaging options are strategies to be recommended and adopted just in the latter population, whilst cessation remains the gold standard to pursue in all cigarette smokers.

In total, 24 statements (Statements 1, 3–9, 19–21, 23–26, 28–34, 37 and 38) reached consensus after two rounds of voting, indicating substantial agreement on a range of issues within three broad areas (1): harm from tobacco smoking and strategies for harm reduction, (2) smoke-free alternatives to cigarettes and (3) anti-smoking legislation.

Despite reaching a consensus on several statements, the Expert Panel remained divided on several issues. For example, divergent opinions were expressed on statements regarding the role of smoke-free alternatives for harm reduction. These disagreements are reflected in the debate that continues to unfold in the scientific literature (6, 23, 24, 27, 45–47). Proponents for the use of smoke-free alternatives for tobacco harm reduction tend to emphasize that most of the harm associated with tobacco use comes from combustion, which is absent in smoke-free alternatives (48). Others have raised concerns about the safety of the chemicals contained in electronic cigarettes and about the possibility that smoke-free tobacco alternatives may serve as a gateway to traditional cigarettes or cause tobacco smokers who have previously quit to relapse (24, 27, 49). However, the most recent data from the Global Youth Tobacco Survey, which was carried out in Italy over the 2021–2022 school year and questioned 2,069 adolescents aged 13–15 years, has indicated that the use of cigarettes and nicotine products overall has decreased over the past 8 years (50). Further, as other interventions and policies have thus far failed to eliminate smoking, despite substantial public policy efforts, it may be that commitment to the goal of complete abstinence on the part of those who are concerned about smoke-free tobacco alternatives prevents them from seeing the value of intermediate solutions (6).

Ultimately, this Delphi study represents a critical approach to understanding expert perspectives that is consistent with the principles of scientific research. Rather than seeking unanimous agreement, the process illuminated diverse viewpoints and fostered nuanced discussion, which is required to addressing the diverse challenges of tobacco harm reduction.

The concept of abstinence as the only possible strategy in tobacco control needs to be critically reviewed. Undoubtedly, complete cessation of smoking is the best possible outcome. However, this focus necessarily overlooks the needs of those who are unwilling or unable to quit entirely. For these individuals, the use of smoke-free products may provide a suitable, if not the only, strategy to substantially reduce their health risks, and harm reduction measures should be recognized as an essential component of public health strategy.

Hesitancy in adopting harm reduction strategies has also been observed in other areas of public health, such as the opioid crisis, where harm reduction strategies have shown substantial benefits in reducing opioid use, lowering the risk of overdose, and preventing the transmission of infectious diseases. However, despite clear evidence of the benefits of harm reduction measures, many experts and policymakers continue to favor abstinence-only approaches, often sidelining the benefits of non-abstinence strategies (51, 52).

This example provides a clear parallel for tobacco control: failing to recognize the value of harm reduction may limit our ability to effectively reduce the burden of smoking-related diseases.

This study was funded by Philip Morris Italia, a subsidiary of Philip Morris International. The funding reflects a continued commitment by the tobacco industry to develop less harmful alternatives for consumers, indicating a clear paradigm shift toward a harm reduction approach, similar to efforts seen in the automotive industry to improve product safety.

While our study was funded by a tobacco company, several steps were taken to ensure the research’s objectivity and integrity. The independence of the research team, the anonymous voting process, and the involvement of an independent methodologist in data analysis were crucial measures taken to mitigate potential conflicts of interest. Transparency in our methodology and full disclosure of the funding source have been paramount, and we believe these steps maintain high standards of scientific rigor. Additionally, we acknowledge the concern that some potential collaborators might have opted out due to the source of funding, which could have influenced the overall composition of the Scientific Committee. However, the rigorous nature of the DELPHI consensus methodology inherently minimizes the potential impact of any selection bias on our work. Even if significant selection bias were to occur at the Scientific Committee level, the iterative procedural steps of the DELPHI consensus allow for agreements/disagreements from many key opinion leaders. Importantly, the key opinion leaders were selected from a pool of 20 scientific societies, comprising health professionals with a diverse range of views on tobacco harm reduction. This diversity enhances the balance and integrity of our analysis.

These ongoing disagreements reflect the complexities and challenges inherent in forming a consensus on a rapidly evolving and contentious field like tobacco harm reduction. Therefore, the findings of this consensus study underscore the need for further research, dialogue and expert discussions to guide policy and practice in this important public health area. In particular, future work should focus on the statements where consensus was not reached, to examine these areas in more depth, and to provide further evidence to guide policy and practice in tobacco harm reduction in Italy. Indeed, the authors suggest that another consensus study be conducted within the next 2 years, given the large amount of scientific evidence likely to be published in the near future in the field of preventable diseases.

While this research centers around the Italian context, the findings can be applied to any nation facing a significant prevalence of smoking. The concepts of reducing tobacco-related harm and the collaborative consensus-building process discussed are universally applicable, offering a framework that can be tailored to address tobacco use as a public health issue in different countries.

The present consensus study had several limitations. Firstly, consensus was based on the opinions of a select group of 20 specialists, which may not encompass the broader perspectives of the larger scientific community. Secondly, as the study was limited to the opinions of Italian experts, the present consensus may not be readily generalizable to specialists in other countries. However, one of the strengths of the present study was the use of a much higher threshold for consensus (>85%) than is commonly used in Delphi studies.

To ensure the integrity and objectivity of our research, the Expert Panel maintained strict independence from the sponsor working independently throughout all stages of the research process. All the conclusions presented in this study reflect the opinions of the authors and have not been influenced by the sponsor. We have fully disclosed our funding source and are committed to transparency, making our methodology and data available for peer review.

In conclusion, this Delphi consensus study represents an important step in establishing expert consensus on the role of smoke-free products in reducing the harm caused by tobacco smoking in Italy. It provides a framework for ongoing dialogue and action, with the ultimate aim of reducing the significant health burden posed by tobacco smoking.