On 2016 Jul 13, Clive Bates commented:

The authors base their advice four main pillars, each of which is unreliable.

First, that we lack evidence of safety. We lack evidence of the complete safety of anything, including medicines, and notably those used in smoking cessation. What matters is the relative risk. We do have good evidence that e-cigarette vapour is much less hazardous than cigarette smoke [1]. Most of the hazardous agents in cigarette smoke are either not present at detectable levels in e-cigarette aerosol or at levels far below those found cigarette smoke. The authors mention diacetyl but fail the basic requirement of risk presentation, which is quantification - magnitude and materiality matter. The levels of diacetyl found in e-cigarettes (if it is used at all) are several hundred times lower than in cigarette smoke, and there are no known cases of 'popcorn lung' in smokers [2]. Overall, the Royal College of Physicians reviewed the safety of e-cigarettes and concluded [3]:

Although it is not possible to precisely quantify the long-term health risks associated with e-cigarettes, the available data suggest that they are unlikely to exceed 5% of those associated with smoked tobacco products, and may well be substantially lower than this figure". (Section 5.5 page 87)

Second, the authors argue that e-cigarettes may be ineffective as a smoking cessation aid. There are few RCTs evaluating these products because they are not medicines, but low-risk consumer alternatives to cigarettes. RCTs are not well suited to evaluating complex behaviour change in a rapidly evolving marketplace. However, there is considerable evidence of smokers using these products as alternatives to smoking and the studies cited by the authors are limited by confounding, selection bias and inappropriate aggregation of heterogeneous studies. May I suggest that interested clinicians cut through the thicket of claims and counterclaims, and read some of the accounts of smokers who's lives have been revolutionised by these products [4]? For the more cautious, e-cigarettes may be an option to suggest once the other options have been exhausted, but the approach certainly should not be discarded in its entirety.

Third, the authors argue that these products are not approved by the FDA and that there are fire and poisoning risks. Regulation by the FDA is no guarantee of safety - many medicines have severe side-effects and cigarettes are regulated by the FDA under the Tobacco Control Act. There have been a few cases of highly publicised e-cigarette battery fires - a small risk with all lithium-ion batteries. But this should be set against fire risks from smoking, which the National Fire Protection Service estimates causes the following damage [5]</p>

In 2011, U.S. fire departments responded to an estimated 90,000 smoking-material fires in the U.S., largely unchanged from 90,800 in 2010. These fires resulted in an estimated 540 civilian deaths, 1,640 civilian injuries and $621 million in direct property damage".

It is true that calls to poison centers rose 'exponentially' along with the growth of the product category from a low base. But the word 'exponential' does not mean 'large'. Calls to US Poison Centers amounted to 4,014 for e-cigarettes in 2014, but that compares with 291,062 for analgesics and 199,291 for cosmetics, and 2.2 million in total [6]. It is a small risk amongst many others common in the home.

Fourth and finally, the authors make a 'first-do-no harm" argument. But paradoxically they create potential serious harm with their chosen analogy:

Jumping from the 10th floor of a burning building rather than the 15th floor offers no real benefit.

This is an implied relative risk claim, which can be interpreted in two ways. First, that cigarettes and e-cigarettes are equally lethal (the likely result of jumping from the 10th and 15th floor is near certain death) or that e-cigarettes offer about two-thirds of the risk of smoking, based on the relative energy of impact (proportional to the distance fallen). Neither is remotely supportable by any evidence, but it this kind of casually misleading risk communication that is likely to cause fewer smokers to switch and more e-cigarette users to relapse. The debate about the relative risk of e-cigarette risk and smoking is better represented by a comparison of stumbling on the building's entrance steps with jumping from the 4th floor, the estimated height causing death in 50% of falls [7]. The weakness and inappropriateness of such analogies have been heavily criticised [8].

These metaphors, like other false and misleading anti-harm-reduction statements are inherently unethical attempts to prevent people from learning accurate health information. Moreover, they implicitly provide bad advice about health behavior priorities and are intended to persuade people to stick with a behavior that is more dangerous than an available alternative. Finally, the metaphors exhibit a flippant tone that seems inappropriate for a serious discussion of health science.

The responsible clinician should be providing accurate, realistic information and advice conveyed in a way that promotes understanding rather than unwarranted fear or confusion and helps the patient make an informed choice. It is important to recognise that smokers are at great risk, and if these products offer and attractive and appealing way out of smoking that works for them the clinician should not be a barrier to them taking that path.

[1] Farsalinos KE, Polosa R. Safety evaluation and risk assessment of electronic cigarettes as tobacco cigarette substitutes: a systematic review. Ther Adv Drug Saf 2014;5:67-86. [Link]

[2] Siegel M. New Study Finds that Average Diacetyl Exposure from Vaping is 750 Times Lower than from Smoking, The Rest of the Story, 10 December 2015. [Link]

[3] Royal College of Physicians, London. Nicotine without smoke:tobacco harm reduction, 28 April 2016 [Link]

[4] Consumer Advocates for Smoke-free Alternatives Associations (CASAA) User testimonials, accessed 12 July 2016 [Link]

[5] Hall J. The Smoking-Material Fire Problem, National Fire Protection Service, July 2013 [Link

[6] Mowry JB, Spyker DA, Brooks DE, et al. 2014 Annual Report of the American Association of Poison Control Centers' National Poison Data System (NPDS): 32nd Annual Report. Clin Toxicol 2015;53:962-1147. [Link].

[7] Marx J, Hockberger R, Walls R. Rosen's Emergency Medicine - Concepts and Clinical Practice, 8th EditionTable 36-1 page 290, August 2013. [Link]

[8] Phillips CV, Guenzel B, Bergen P. Deconstructing anti-harm-reduction metaphors; mortality risk from falls and other traumatic injuries compared to smokeless tobacco use. Harm Reduct J 2006;3:15.[Link]

Competing interests: I am a longstanding advocate for 'harm reduction' approaches to public health. I was director of Action on Smoking and Health UK from 1997-2003. I have no competing interests with respect to any of the relevant industries.

On 2016 Jul 13, Clive Bates commented:

The authors base their advice four main pillars, each of which is unreliable.

First, that we lack evidence of safety. We lack evidence of the complete safety of anything, including medicines, and notably those used in smoking cessation. What matters is the relative risk. We do have good evidence that e-cigarette vapour is much less hazardous than cigarette smoke [1]. Most of the hazardous agents in cigarette smoke are either not present at detectable levels in e-cigarette aerosol or at levels far below those found cigarette smoke. The authors mention diacetyl but fail the basic requirement of risk presentation, which is quantification - magnitude and materiality matter. The levels of diacetyl found in e-cigarettes (if it is used at all) are several hundred times lower than in cigarette smoke, and there are no known cases of 'popcorn lung' in smokers [2]. Overall, the Royal College of Physicians reviewed the safety of e-cigarettes and concluded [3]:

Although it is not possible to precisely quantify the long-term health risks associated with e-cigarettes, the available data suggest that they are unlikely to exceed 5% of those associated with smoked tobacco products, and may well be substantially lower than this figure". (Section 5.5 page 87)

Second, the authors argue that e-cigarettes may be ineffective as a smoking cessation aid. There are few RCTs evaluating these products because they are not medicines, but low-risk consumer alternatives to cigarettes. RCTs are not well suited to evaluating complex behaviour change in a rapidly evolving marketplace. However, there is considerable evidence of smokers using these products as alternatives to smoking and the studies cited by the authors are limited by confounding, selection bias and inappropriate aggregation of heterogeneous studies. May I suggest that interested clinicians cut through the thicket of claims and counterclaims, and read some of the accounts of smokers who's lives have been revolutionised by these products [4]? For the more cautious, e-cigarettes may be an option to suggest once the other options have been exhausted, but the approach certainly should not be discarded in its entirety.

Third, the authors argue that these products are not approved by the FDA and that there are fire and poisoning risks. Regulation by the FDA is no guarantee of safety - many medicines have severe side-effects and cigarettes are regulated by the FDA under the Tobacco Control Act. There have been a few cases of highly publicised e-cigarette battery fires - a small risk with all lithium-ion batteries. But this should be set against fire risks from smoking, which the National Fire Protection Service estimates causes the following damage [5]</p>

In 2011, U.S. fire departments responded to an estimated 90,000 smoking-material fires in the U.S., largely unchanged from 90,800 in 2010. These fires resulted in an estimated 540 civilian deaths, 1,640 civilian injuries and $621 million in direct property damage".

It is true that calls to poison centers rose 'exponentially' along with the growth of the product category from a low base. But the word 'exponential' does not mean 'large'. Calls to US Poison Centers amounted to 4,014 for e-cigarettes in 2014, but that compares with 291,062 for analgesics and 199,291 for cosmetics, and 2.2 million in total [6]. It is a small risk amongst many others common in the home.

Fourth and finally, the authors make a 'first-do-no harm" argument. But paradoxically they create potential serious harm with their chosen analogy:

Jumping from the 10th floor of a burning building rather than the 15th floor offers no real benefit.

This is an implied relative risk claim, which can be interpreted in two ways. First, that cigarettes and e-cigarettes are equally lethal (the likely result of jumping from the 10th and 15th floor is near certain death) or that e-cigarettes offer about two-thirds of the risk of smoking, based on the relative energy of impact (proportional to the distance fallen). Neither is remotely supportable by any evidence, but it this kind of casually misleading risk communication that is likely to cause fewer smokers to switch and more e-cigarette users to relapse. The debate about the relative risk of e-cigarette risk and smoking is better represented by a comparison of stumbling on the building's entrance steps with jumping from the 4th floor, the estimated height causing death in 50% of falls [7]. The weakness and inappropriateness of such analogies have been heavily criticised [8].

These metaphors, like other false and misleading anti-harm-reduction statements are inherently unethical attempts to prevent people from learning accurate health information. Moreover, they implicitly provide bad advice about health behavior priorities and are intended to persuade people to stick with a behavior that is more dangerous than an available alternative. Finally, the metaphors exhibit a flippant tone that seems inappropriate for a serious discussion of health science.

The responsible clinician should be providing accurate, realistic information and advice conveyed in a way that promotes understanding rather than unwarranted fear or confusion and helps the patient make an informed choice. It is important to recognise that smokers are at great risk, and if these products offer and attractive and appealing way out of smoking that works for them the clinician should not be a barrier to them taking that path.

[1] Farsalinos KE, Polosa R. Safety evaluation and risk assessment of electronic cigarettes as tobacco cigarette substitutes: a systematic review. Ther Adv Drug Saf 2014;5:67-86. [Link]

[2] Siegel M. New Study Finds that Average Diacetyl Exposure from Vaping is 750 Times Lower than from Smoking, The Rest of the Story, 10 December 2015. [Link]

[3] Royal College of Physicians, London. Nicotine without smoke:tobacco harm reduction, 28 April 2016 [Link]

[4] Consumer Advocates for Smoke-free Alternatives Associations (CASAA) User testimonials, accessed 12 July 2016 [Link]

[5] Hall J. The Smoking-Material Fire Problem, National Fire Protection Service, July 2013 [Link

[6] Mowry JB, Spyker DA, Brooks DE, et al. 2014 Annual Report of the American Association of Poison Control Centers' National Poison Data System (NPDS): 32nd Annual Report. Clin Toxicol 2015;53:962-1147. [Link].

[7] Marx J, Hockberger R, Walls R. Rosen's Emergency Medicine - Concepts and Clinical Practice, 8th EditionTable 36-1 page 290, August 2013. [Link]

[8] Phillips CV, Guenzel B, Bergen P. Deconstructing anti-harm-reduction metaphors; mortality risk from falls and other traumatic injuries compared to smokeless tobacco use. Harm Reduct J 2006;3:15.[Link]

Competing interests: I am a longstanding advocate for 'harm reduction' approaches to public health. I was director of Action on Smoking and Health UK from 1997-2003. I have no competing interests with respect to any of the relevant industries.