吸电子烟真的比吸烟好嘛？

吸电子烟真的比吸烟好嘛？

近年来，电子香烟成为那些渴望健康生活却又不能戒除烟瘾的人们的新选择。电子香烟的推广使其成为了一个新兴的研究领域。然而电子香烟真的如同宣传的那样对人体危害更小吗？最新的研究结果将为我们揭晓这个答案。

测试中可能遇到的词汇和知识：

Vape吞云吐雾（特指电子水烟）

Exhalation蒸发，呼气；散发物[eksə'leɪʃ(ə)n]

Combustible可燃的，易燃的[kəm'bʌstɪb(ə)l]

Peril危险；冒险；危及['perɪl]

Carcinogen致癌物质[kɑː'sɪnədʒ(ə)n]

Obfuscate使模糊使混乱['ɒbfʌskeɪt]

Is it better to vape than to smoke?（842 words）

By Anjana Ahuja

They seem most visible when the wind blows in from the Arctic — small clusters punctuating the empty streets,white sticks clasped between blue fingers and their exhalations drifting across No Smoking signs.

Smokers are,in all respects,a dying breed. In England in 2015,16.9 per cent of people described themselves as smokers,compared with 19.3 per cent in 2012. About a third tried to give up in the past 12 months.

Those who carry on puffing suffer higher rates of cancer,heart disease,respiratory disease and stroke than non-smokers. The National Health Service estimated that 78,000 deaths in 2014 were attributable to the habit.

Many smokers have considered turning to electronic cigarettes,which are“vaped”rather than smoked,in order to quit. Ecigarettes are a recent development in tobacco harm-reduction and are marketed as a less harmful alternative to smoking. But a stream of conflicting stories about their benefits,or otherwise,has left consumers confused.

Last month,for example,several newspapers including the Daily Mail,The Times and The Sun,reported research that suggested certain flavours of ecigarettes may harm sperm. The findings were presented at a British Fertility Society conference but are yet to be published in a journal.

There is,however,a strong scientific consensus that vaping is far better for health than smoking（although it is best to neither vape nor smoke). This consensus was reinforced by a study published this week in the Annals of Internal Medicine.

Ecigarettes have been barely regulated until recently,meaning that their ingredients are not always known. In the past,e-liquid and vapour have been found to contain toxins such as carbonyls,tobacco-specific N-nitrosamines（TSNAs) and heavy metals,which can also be found in tobacco smoke.

This similarity constitutes one reason why their risk level has been a concern. The new study suggests vapers have a lower exposure to these toxins than smokers and hence are subject to a lower risk to health.

Researchers led by Dr Lion Shahab at University College London looked at five groups of long-term nicotine users. They were: regular smokers; former smokers who now only used ecigarettes; former smokers who only used nicotine replacement therapy such as patches or gum; smokers who also used ecigarettes,and smokers using nicotine replacements.

There were 181 participants,and their saliva and urine were tested for biomarkers of nicotine,carcinogens and other toxins.

Dr Shahab found that those who used only ecigarettes received a similar nicotine hit to smokers,while benefiting from substantially lower exposure to toxins and carcinogens. By extrapolation,lower exposure suggests lower levels of eventual harm.

The dual users who smoked and vaped were subject to exposures as high as smokers,for reasons that are as yet unclear. Thus smokers who want to improve their health are advised to completely give up combustible cigarettes rather than mix them with ecigarettes or nicotine patches.

The work,funded by Cancer Research UK,confirms that“full cessation of all nicotine products remains the best option to avoid harm”.

The finding echoes other analyses,such as a 2014 systematic review in the journal Therapeutic Advances in Drug Safety,which concluded“electronic cigarettes are by far a less harmful alternative to smoking . . .”and that considerable health benefits accrue from switching. Public Health England states that vaping is 95 per cent safer than smoking.

Put simply,there is a spectrum of peril: smoking regular cigarettes exposes you to considerable known harms; ecigarettes and nicotine patches offer lower exposure and by implication less harm. And of course,steer clear of all nicotine products if you know what is best for you.

At a briefing at the Science Media Centre in London last week,Professor Robert West,editor-in chief of the journal Addiction,offered an insightful précis of how the clear,simple message that vaping is safer than smoking had become lost in the haze:“We see a constant drip-drip of them [studies into ecigarettes]: small studies,studies in mice; studies without cigarettes as a comparator,studies looking at risk where the level of risk isn’t quantified.”

The novelty of the products means that long-term surveys of vaping are decades away,leaving the knowledge gap ripe for filling by the kind of studies alluded to by Professor West.

In addition,the“to vape or not to vape”dilemma is coloured by an association with the absurdly powerful tobacco industry,which has long obfuscated and dissembled over the sheer deadliness and addictiveness of its products.

This has led to another criticism of vaping: it lures people into smoking. Research is trying to elucidate whether children who vape and then smoke would have ended up smoking anyway. The hotly contested“gateway”argument is separate and important but should not be conflated with the issue of relative toxicity.

And what if you have not tried any form of tobacco? Just say no,full stop,to both vaping and smoking — to the unpleasant smell,to the unnecessary expense,to the raised risks of disease（whatever they turn out to be) and,of course,to being forced out into the cold.