In this study, we investigated self-rated health among exclusive e-cigarette users compared to exclusive cigarette smokers, providing insights into subjective health perceptions among users of different nicotine delivery systems. Our findings revealed that exclusive e-cigarette users were significantly more likely to report good health compared to exclusive cigarette smokers, even after adjusting for multiple demographic and health-related covariates in a binary logistic regression model. Sensitivity analyses using a generalized ordered logistic regression model with the original five-category self-rated health variable confirmed these results, demonstrating a stable and reliable association across modeling approaches. This aligns with previous findings where both dichotomous and ordinal models yielded comparable results in analyzing self-rated health [30]. Together, these results suggest that the relationship between e-cigarette use and better self-rated health is robust, minimizing concerns about model instability. This observation is particularly important as it reflects a broader trend noted in public health research, where e-cigarettes have been positioned as a potentially less harmful alternative to traditional cigarettes [32,33,34,35].

The narrative that e-cigarettes may contribute to harm reduction, as suggested by evidence including the Public Health England review, supports our findings that users of e-cigarettes perceive their health more positively [13]. Recent data from Action on Smoking and Health further reinforce this, showing that e-cigarettes have been the most popular aid for quitting smoking in the UK over the past 5 years, with 2.7 million people using them to quit [15]. Moreover, population-level studies have shown that e-cigarettes are also associated with lower smoking prevalence across populations [34, 35]. This overall decline in smoking rates may lead to improved health outcomes and perceptions, as fewer individuals are exposed to the harmful effects of traditional cigarettes. Consequently, the positive self-rated health among exclusive e-cigarette users observed in our study may reflect these broader public health trends.

While self-rated health offers useful insights into personal health perceptions, objective measures provide a more concrete assessment of the physiological impact of e-cigarette use. Several studies have reported potential cardiovascular and respiratory benefits for smokers who switch to e-cigarettes. For instance, research has shown that smokers who transition to e-cigarettes experience improvements in cardiovascular parameters such as reductions in systolic blood pressure, endothelial function improvements, and reduction in arterial stiffness [36,37,38,39,40]. These findings suggest that e-cigarettes may help mitigate some of the cardiovascular risks associated with traditional smoking, at least in the short term. Similarly, in terms of respiratory health, studies have noted improvements in lung function and pulmonary ventilation and decreases in airway resistance among smokers who switched to e-cigarettes [41, 42], pointing to a potential benefit in reducing the harm caused by tobacco smoke.

In addition to cardiovascular and respiratory improvements, a recent systematic review and meta-analysis found that exposure to tobacco-specific nitrosamines (TSNAs)—potent carcinogens found in tobacco smoke—was significantly lower among exclusive e-cigarette users compared to exclusive cigarette smokers [43]. The study reported substantial reductions in TSNA levels when individuals switched from smoking to e-cigarettes, indicating decreased exposure to harmful carcinogens. This reduction in carcinogen exposure may potentially lower the risk of cancer and other diseases linked to TSNAs, such as cardiovascular and respiratory illnesses, among e-cigarette users compared to traditional smokers. Such objective improvements in health risk profiles may enhance individuals’ self-rated health, as they recognize the benefits of reduced exposure to harmful substances. The psychological reassurance of making a healthier choice and reducing one’s risk of serious illnesses could contribute to the higher self-rated health reported by exclusive e-cigarette users in our study.

On the other hand, not all studies have reported such benefits. Some research has found no significant improvements in cardiovascular or respiratory markers, and in some cases, switching to e-cigarettes has been associated with negative impacts on these markers and other objective parameters [45,46,47,48]. These mixed results also suggest that the potential benefits of e-cigarettes on health may vary depending on individual factors such as the duration of smoking, baseline health status, or the specific type of e-cigarette used. While the evidence is indeed mixed, with some studies showing clear benefits and others demonstrating no benefits, the harm reduction effect of e-cigarettes compared to traditional smoking is widely acknowledged. By eliminating combustion, which is responsible for many of the toxic substances in cigarette smoke, e-cigarettes offer a less harmful alternative. Nonetheless, it is important to continue gathering objective data, particularly through long-term studies, to fully assess the benefits and potential risks of e-cigarette use in comparison to traditional smoking.

Despite the reliance on subjective measures in our study, it remains relevant in contributing to ongoing debates about nicotine use and harm reduction. Self-rated health is widely recognized in public health as a useful indicator of how individuals view their own well-being, which can inform broader understanding of health behaviors and interventions [18, 49]. Although it may not provide direct evidence of harm reduction, the fact that e-cigarette users report better perceived health than smokers is still meaningful, especially in contexts where public health messaging strongly promotes e-cigarettes as a safer alternative. Importantly, this study aligns with previous research suggesting that individuals may perceive e-cigarettes as less harmful [50, 51], contributing to harm reduction frameworks that aim to reduce the adverse impacts of smoking on populations. Thus, while self-reported health status does not equate to medical or long-term health outcomes, the perceptions captured in this study offer insight into the personal experiences of nicotine product users, which remains significant for public health policies and harm reduction strategies. Contextually, the shift toward e-cigarettes as an alternative to traditional cigarettes has grown, with over 82 million users worldwide, many of whom have switched from traditional smoking [10, 52]. Understanding how these individuals perceive their health post-switch is pertinent, as self-rated health is often used to gauge immediate health perceptions. Public health strategies should take these subjective perceptions into account, alongside objective evidence, to guide interventions aimed at promoting smoking cessation and harm reduction. Although public health authorities continue to explore the full health implications of e-cigarettes, studies like this one provide valuable insights into user experiences, which can influence behavior and inform public health policy.

This study’s strength lies in its comprehensive analysis of self-rated health outcomes among exclusive e-cigarette users and cigarette smokers, utilizing a large, representative sample from the Health Survey for England 2019. Our inclusion of key demographic and health-related covariates ensures that our findings are adjusted for factors such as age, sex, education, and health conditions, lending credibility to the comparisons drawn between these two groups. Moreover, this study fills a gap in the literature by focusing on exclusive users, providing insights into the health perceptions of individuals who engage in distinct nicotine consumption behaviors without the confounding effects of dual use.

However, several limitations must be acknowledged. The reliance on self-reported data introduces potential biases, as individuals may be influenced by external factors such as public health messaging that positions e-cigarettes as a healthier alternative. This perception bias, which is particularly strong in the UK, could have led e-cigarette users to report better health than cigarette smokers, regardless of their actual health status. Nonetheless, the consistency of the self-reported health data with the harm reduction narrative widely supported in the literature suggests that this bias may not have significantly affected the overall findings. In addition, residual confounding due to unmeasured variables cannot be ruled out, which may influence the observed associations. While this study adjusted for age started smoking—an important factor in understanding early nicotine exposure—it did not fully account for the duration of nicotine use. Duration is important, as long-term and short-term users of either nicotine product may experience different health trajectories [53]. Future research should aim to capture cumulative nicotine exposure over time, which may provide a more complete picture of health outcomes. Despite these limitations, the adjustments for demographic and health-related covariates help ensure that the findings provide insights into general health perceptions among nicotine users. Although small cell sizes in certain subgroups, such as underweight e-cigarette users, may reduce the precision of estimates for these categories, the overall sample size and model performance remain robust.

The cross-sectional design further limits our ability to infer causality or long-term health outcomes, as self-rated health at a single point in time does not capture changes in health over extended periods [54, 55]. However, the associations observed provide an important snapshot of health perceptions, which are highly relevant for public health messaging and interventions, particularly in understanding the immediate impacts of switching to e-cigarettes. Finally, the exclusion of participants under 16 years of age limits the generalizability of these findings to the entire population of nicotine users. Nonetheless, focusing on adult populations is particularly relevant, as they represent the majority of e-cigarette and traditional cigarette users, making the findings highly applicable to key target groups in harm reduction strategies.

Future research should focus on addressing the limitations identified in this study. First, longitudinal studies are needed to track health outcomes over time, allowing researchers to examine the long-term effects of exclusive e-cigarette use versus traditional smoking. This would provide stronger evidence for or against the harm reduction potential of e-cigarettes. In addition, the duration of nicotine product use should be factored into future analyses, as long-term exposure may present different health risks or benefits compared to short-term use. Exploring the role of social messaging in shaping health perceptions could also offer valuable insights into how public health campaigns influence behavior and self-reported health. Expanding the scope of research to include underage users, dual users, and individuals who use other nicotine products (e.g., heated tobacco or nicotine pouches) would provide a more comprehensive understanding of nicotine consumption patterns and their health impacts. Finally, combining subjective measures like self-rated health with objective health outcomes (e.g., respiratory function tests or cardiovascular assessments) would create a more holistic view of the health implications of e-cigarettes, ultimately guiding more effective harm reduction and smoking cessation strategies.