Smoking without fire有烟无火

                                                                                  The Economist September 22nd 2018
Vaping 电子烟

Smoking without fire

有烟无火

陈继龙 译

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E-cigarettes are far healthier than smoking. That does not mean they are benign

电子烟比卷烟健康得多，但并不意味着电子烟无害

Studies in mice have confirmed that the vapour can induce an inflammatory response in the lungs.

    For decades, doctors and governments have been trying to wean smokers from their habit. It is a tricky task. Nicotine is as addictive as heroin and cocaine. There are plenty of officially endorsed methods for quitting. People can try inhalators, gum, lozenges, patches, nasal sprays and prescription drugs. All can help, but few replicate all the physical and social rituals that surround cigarettes.That limits how appealing they are to committed smokers.

        几十年来，医生和政府一直在努力让烟民戒除吸烟习惯。这是一件很难办的事情。尼古丁与海洛因、可卡因一样容易成瘾。经过官方认证的戒烟方法有很多，人们可以使用雾化吸入器、口香糖、含片、贴片、喷鼻剂和处方药等来尝试戒烟。这些方法可能都有所助益，但从生理和社会角度看，很少能让人产生与香烟完全相同的体验，因此对于烟瘾很大的人来说，它们的吸引力有限。

    It was into this mix that e-cigarettes arrived about a decade ago. Unlike ordinary cigarettes, which rely on burning tobacco to deliver their payload, e-cigarettes use an electric charge to vaporise a dose of nicotine (accompanied, often, by various flavouring chemicals). They have proved extremely popular, particularly in America, Britain and Japan. Public-health officials have been quick to conclude that they are much better than smoking. Consumers, says Robert West, a professor of health psychology at University College London, are “voting with their lungs”.

        大约十年前，电子烟跻身此类戒烟用品行列。普通香烟通过烟草的燃烧来释放物质，电子烟则不同，它是用电荷气化一定剂量的尼古丁（随之释放的还有各种香味的化学物质）。事实证明，电子烟非常受欢迎，特别是在美国、英国和日本。公共卫生官员迅速得出结论：抽电子烟比抽香烟要好得多。伦敦大学学院健康心理学教授罗伯特·韦斯特说，消费者“正在用他们的肺投票”。

    Still, not everyone is happy. E-cigarettes are new, so information about their effects is still scarce. Others worry about who is using them. The Food and Drug Administration, an American regulator, says it has data showing an “epidemic” of vaping among teenagers which it will release in the coming months. Earlier this month it put e-cigarette firms on notice that they must try to combat underage use of their products or face sanction.How worried should vapers—or their parents—be?

        然而，并不是每个人都开心。电子烟属于新生事物，因此与其效果相关的资讯仍然少之又少。还有人对谁在使用电子烟感到担忧。美国监管机构——食品及药物管理局（FDA）称其已有数据显示，青少年开始“流行”抽电子烟。FDA将在未来几个月里公布这一数据。本月早些时候，FDA对电子烟公司发出警告，要求他们必须防止未成年人使用其产品，否则将面临处罚。电子烟民或者他们的父母到底会有多担心呢？

    The chemistry is the best place to start. Cigarette smoke is genuinely nasty stuff. It contains about 70 carcinogens, as well as carbon monoxide (a poison), particulates, toxic heavy metals such as cadmium and arsenic, oxidising chemicals and assorted other organic compounds.

        我们最好先从化学说起。香烟烟雾真的非常肮脏，含有约70种致癌物，此外还有一氧化碳（有毒物质）、颗粒物、有毒重金属（如镉和砷）、氧化剂以及各种其他有机化合物。

    The composition of e-cigarette vapour varies between brands. A best guess suggests that, instead of the thousands of different compounds in cigarette smoke, it contains merely hundreds. Its main ingredients—propylene glycol and glycerol—are thought to be mostly harmless when inhaled. But that is not certain. People with chronic exposure to special-effect fogs used in theatres—which contain propylene glycol—have reported respiratory problems. Nitrosamines, a carcinogenic family of chemicals, have been found in e-cigarette vapour, albeit at levels low enough to be deemed insignificant. Metallic particles from the device’s heating element, such as nickel and cadmium, are also a concern.

        就电子烟而言，气化物化学成分因品牌而异。最乐观的估测是，香烟烟雾中不同的化合物是数以千计，而它仅是数以百计，其主要成分丙二醇和甘油，被认为吸入后通常不会对人体产生毒害。不过，这也不一定。据报告，长期接触含有丙二醇的剧场特效烟雾的人出现了呼吸道疾病。在电子烟雾中，人们还发现了一类致癌化学物质——亚硝胺，尽管其含量非常少，以至于无关紧要。该设备加热元件产生的金属颗粒，如镍和镉，同样值得关注。

    Some studies have found that e-cigarette vapour can contain high levels of unambiguously nasty chemicals such as formaldehyde, acetaldehyde and acrolein, all derived from other ingredients that have been exposed to high temperatures. The vapour also contains free radicals, highly oxidising substances which can damage tissue or DNA, and which are thought to come mostly from flavourings. According to work published this January flavourings such as cinnamon, vanilla and butter generate the most.

        一些研究发现，电子烟雾中可能含有浓度很高而且无疑十分有害的化学物质，比如甲醛、乙醛和丙烯醛，它们均是在高温条件下从其他成分中分解而来的。气雾中还包含氧化性极强的自由基，会对人体组织或DNA造成损伤。这些自由基据称大多来自调味成分。今年1月发布的研究成果显示，肉桂、香草、黄油等调味料产生的自由基最多。

    Several studies in mice have confirmed that the vapourcan induce an inflammatory response in the lungs. In June, for example, Laura Crotty Alexander at the University of California San Diego and her colleagues published results which showed that e-cigarette vapour has a variety of unpleasant effects, inducing kidney dysfunction and a thickening and scarring of connective tissue in their hearts called fibrosis. Her data suggest that the vapour may also be disrupting the epithelial barrier that lines the lungs,triggering inflammation. They speculate that this could make it easier for pathogens like bacteria to take hold.That would fit with recent work by Lisa Miyashita at Queen Mary University of London, which found that vaping makes cells lining the airways stickier and more susceptible to bacterial colonisation.

        几项在老鼠身上的研究证实，电子烟雾可诱发肺部炎症反应。例如，2018年6月，加州大学圣地亚哥分校的劳拉·克罗蒂·亚历山大及其同事发表的研究结果表明，电子烟雾能产生诸多不良影响，会引发肾功能障碍，并导致心脏结缔组织增厚和瘢痕形成即纤维化。她的数据显示，气雾还可能会破坏肺内的上皮细胞屏障，引起炎症。他们推测，这会让细菌之类的病原体更易在人体内扎根。无独有偶，伦敦大学玛丽女王学院的宫下丽莎最新研究也发现，气雾会让气道壁上的细胞粘度增加，更易遭细菌侵袭。

Puffed up

来一口电子烟

    It all sounds worrying. But a dose of scepticism is useful too. One alarming study in August said that e-cigarette users are more likely to have been diagnosed with cardiovascular disease. But many vapers have smoked in the past, or still do. The paper may have been picking up old harms from smoking, rather than new ones from vaping. Many think that the toxic nature of e-cigarette vapour may have been exaggerated by unrealistic laboratory conditions. Overheating the fluid creates an unpleasant taste that users actively avoid. Lab tests may heat the fluid more vigorously than real vapers do, for example.

        一切听上去都让人忧心忡忡，不过一定的质疑也是有益处的。8月一项惊人的研究称，电子烟民罹患心血管疾病的可能性更大。但是，许多电子烟民过去乃至现在仍在抽香烟。这份报告统计的或许只是抽香烟引发的陈旧性损伤，而不是因电子烟雾所致的新发损伤。许多人认为，电子烟雾的毒性可能因实验室条件脱离实际而被夸大了。比如说，液体过热会产生令人不适的气味，烟民会主动避免。实验中可能会对液体加热过度，而实际上电子烟民并不会如此。

    The last piece of the puzzle is the nicotine. Besides being addictive, it is known to have an adverse affect all around the body. But the current source of concern is its effects on children. For instance, work in animals suggests that exposure to nicotine could be bad for adolescent brains,making users more susceptible to other addictive substances later in life. This could be one reason why human smokers who start young have higher rates of addiction as adults. It might also mean that children who vape risk a life long addiction to nicotine, and may even start smoking. But, says Dr West, these concerns have not yet been borne out by epidemiological studies.

        最后一个谜题是“尼古丁”。 众所周知，除了易于成瘾，尼古丁还会对全身造成不良影响。不过就目前来看，人们主要担心的是其对儿童的影响。例如，动物研究表明，长期接触尼古丁对青春期的大脑有害，使青少年在以后的生活中，更容易对其他成瘾物质产生依赖。这可能也是从小就开始吸烟的人成年后成瘾率更高的原因之一。此外，它还意味着，抽电子烟的儿童存在终生依赖尼古丁的风险，甚至会开始吸烟。但是，韦斯特说，这些令人担忧的情况至今尚未得到流行病学研究证实。

    Smoking during adolescence has also been associated with lasting cognitive and behavioural impairments, including on working memory and attention. Animal tests suggest that exposure to nicotine specifically could explain at least some of that effect. All this forms the scientific backdrop to the FDA’s worries about the effects of vaping among the young.

        青春期吸烟也与包括机械记忆、注意力在内的认知和行为持续性障碍存在关联。动物实验表明，特异性接触尼古丁后至少会出现其中部分问题。从所有这些科学研究来看，担心电子烟给年轻人带来的影响，FDA并非杞人忧天。

    Getting definitive answers will take time. Epidemiology is a tricky business. All sorts of confounding factors and overlooked connections can skew conclusions.Smoking stands out in medical history as a pastime which is so unambiguously bad for you that the signal cuts through almost any amount of noise. The truth about e-cigarettes will take longer to tease out.

        获知明确的答案尚需时日。流行病学研究非常复杂，各种混杂的因素及被忽视的关联都会让结论有失偏颇。医学早已证实，吸烟显而易见只是一种消遣方式，其对人体的有害性几乎无可争辩。至于电子烟，揭开真面目还需要更长的时间。

    That may sound frustratingly vague. But it points toat least one clear conclusion—whether it is harmless or only moderately bad for you, vaping is almost certainly safer than smoking. That is a message which needs spreading. In Britain about a third of smokers say they have not tried vaping because they are worried about its safety and addictiveness. This attachment to a known evil is self-defeating. At least for now, the e-cigarette looks likea useful innovation in public health.

        如此含混不清的说法听起来不免让人沮丧，不过它至少得出一个清晰的结论：抽电子烟不论是无害还是稍有害处，几乎可以肯定比抽香烟更安全。这一信息需要广而播之。英国三分之一的烟民表示，他们之所以没有尝试电子烟，是因为对其安全性和成瘾性有所顾虑。明知吸烟之祸害却依然故我，到最后只能自食其果。最起码就现在来看，电子烟在公共卫生领域算是一种有益的创新了。