Reply to: “Nicotine or tobacco abstinence?”

Reply to R.L. Murray and co-workers:

9 years ago, in July 2013, a group of 12 experts, many who had previously expressed support for e-cigarettes, rated the relative harm of 12 nicotine-containing products by using 14 criteria addressing harms to the users and others [1]. The group concluded e-cigarettes were substantially less harmful than combustible cigarettes. The popular media have taken up these results and promoted e-cigarettes as “95% less risky” or “95% less harmful” than combustible cigarettes. However, the authors acknowledged, “a limitation of this study is the lack of hard evidence for the harms of most products on most of the criteria” [1].

Despite this lack of “hard” evidence, Public Health England endorsed and publicised the “95% less harmful” assertion in 2015 [2]. Researchers clearly pointed out the “invalidity” of this estimate [3], and tried to explain the “English exceptionalism” on e-cigarettes [4]. Even so, R.L. Murray and colleagues used the “95% less harmful” assertion as the main argument in their response to our paper [5].

Since 2013, research on e-cigarettes has rapidly accumulated. Today, there is substantial evidence that using e-cigarettes is harmful to cardiovascular [6] and respiratory health [7]. Indeed, in 2019, an editorial in the Lancet stated that “no solid evidence base” underpins the marketing claims that e-cigarettes are healthier than cigarettes or that they can support quitting [8].

Unproven claims that e-cigarettes are useful harm-reduction tools are further undermined by their high uptake among young people, and the elevated risk of switching from e-cigarettes to combustible cigarettes. Results of the latest meta-analysis of 25 cohort studies confirm this concern, by showing that ever users of e-cigarettes at a young age had over three times the risk of ever cigarette use later on [9].

Discussions regarding the potential harms of e-cigarettes remind us of scientific debates about the health effects of cigarette use in the 1940s and 1950s. Smoking tobacco was apparently not even suspected as a cause of lung tumours, which were very infrequent at that time, until the final decade of the 19th century. It took us half a century to establish cigarette smoking as the leading cause of lung cancer. The true impact of vaping on health will manifest over the coming decades, but the evidence to date on the deleterious effects of e-cigarettes on health justifies the recommendation to abstain from the consumption of inhaled nicotine and other products. This recommendation is endorsed by a substantial number of international societies, including the Forum of International Respiratory Societies [10, 11], the European Academy of Paediatrics [12], and the American Cancer Society [13].