Electronic cigarettes have the potential to contribute to reducing death and disability caused by Britain's biggest killer, say experts in The BMJ today.

Reviewing a new report by the Royal College of Physicians (RCP) on the role of e-cigarettes in tobacco harm reduction, Professor John Britton and colleagues argue that e-cigarettes and other non-tobacco nicotine products "offer the potential to radically reduce harm from smoking in our society. This is an opportunity that should be managed, and taken."

They explain that, despite declining prevalence over recent decades, there are still nearly nine million smokers in the UK - a high proportion of whom are from among the most disadvantaged in our society - and smoking is still the largest avoidable cause of premature death, disability and social inequalities in health in the UK.

However, they point out that, even at the doses absorbed from cigarettes, nicotine causes little if any harm. It is the carcinogens, carbon monoxide and thousands of other toxins in tobacco smoke that kill.

This means that health harms from smoking can be avoided by substituting cigarettes with a less toxic source of nicotine.

The emergence of e-cigarettes has revolutionised the choice of nicotine products available to smokers, write the authors. An estimated 2.6 million people currently use e-cigarettes in the UK, almost all of whom are or have been smokers, and one third of whom no longer smoke.

There have been many concerns raised about the use of e-cigarettes, including attracting young people to become smokers, re-establishing the act of inhaling nicotine as something that is acceptable in public, and diverting smokers who want to quit away from evidence-based smoking cessation treatment services.

But the new RCP report argues that, whilst not absolutely safe, the hazard to health arising from long term vapour inhalation from the e-cigarettes available today is unlikely to exceed 5% of the harm from smoking tobacco.

The report finds that among adults in the UK, e-cigarette use is almost entirely limited to those who are or have been smokers, in most cases as a means to cut down or quit smoking.

It also finds no grounds to suspect that use of e-cigarettes renormalises smoking, or that use where smoking is prohibited represents a significant hazard to health. And it concludes that the availability of e-cigarettes is unlikely to account for the recent decline in number of smokers accessing stop smoking services.

The report recognises that tobacco industry acquisition of many formerly independent e-cigarette producers and importers is a cause for concern, but says that advertising restrictions due to be implemented in May 2016 "go some way towards alleviating these concerns."

The evidence summarised in the RCP report shows that e-cigarettes have so far been beneficial to UK public health, both at individual and population level, by providing smokers with a viable alternative to tobacco smoking, write the authors.

"E-cigarettes represent an important means to reduce the harm to individuals and society from tobacco use, they conclude. "They should continue to be supported by government and promoted as a tobacco harm reduction strategy."

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