经济学人下载:孤独会对你的健康不利的原因

Science and Technology Healthy living Mind and body
科技 健康生活 身与心

The reason loneliness could be bad for your health
孤独会对你的健康不利的原因

SCIENCE has many uses, but it doesn't often produce handy pick-up lines. Recent work on the genetics of disease, however, suggest a way of opening a conversation with that solitary attractive stranger in a bar: loneliness can make you ill.
科学有很多用处，但是它通常不会给你顺口的搭讪理由。然而，近来对疾病遗传学的研究却给了我们一个在酒吧里跟某个孤单的吸引你的陌生人搭讪的理由：孤独会让你生病。

Lonely people, it seems, are at greater risk than the gregarious of developing illnesses associated with chronic inflammation, such as heart disease and certain cancers. According to a paper published last year in the Public Library of Science, Medicine, the effect on mortality of loneliness is comparable with that of smoking and drinking. It examined, and combined the results of, 148 previous studies that followed some 300,000 individuals for an average period of 7.5 years each, and controlled for factors such as age and pre-existing illness. It concluded that, over such a period, a gregarious person has a 50% better chance of surviving than a lonely one.
孤独的人跟爱交际的人相比，似乎患跟慢性炎症相关的疾病——如心脏病和某些癌症——的风险更大。据去年发表在《科学公共图书馆——医学》杂志上的一篇论文称，孤独对死亡率的影响跟抽烟和酗酒相当。文章仔细检查了148个先前的研究（这些研究跟踪观察了大约30万人，每人平均跟踪观察7年半），并综合其结果，还控制了诸如年龄和已患疾病此类因素，最后下结论：超过这样一段时间，一个爱交际的人比一个孤独的人的生存率高50%。

Steven Cole of the University of California, Los Angeles, thinks he may know why this is so. He told the AAAS meeting in Washington, DC, about his work studying the expression of genes in lonely people. Dr Cole harvested samples of white blood cells from both lonely and gregarious people. He then analysed the activity of their genes, as measured by the production of a substance called messenger RNA. This molecule carries instructions from the genes telling a cell which proteins to make. The level of messenger RNA from most genes was the same in both types of people. There were several dozen genes, however, that were less active in the lonely, and several dozen others that were more active. Moreover, both the less active and the more active gene types came from a small number of functional groups.
加州大学洛杉矶分校的Steven Cole认为他可能知道这是为什么。他在华盛顿特区举办的美国科学促进会大会上展示了他对孤独的人的基因表达所做的研究。Cole博士收集了孤独之人和爱交际之人的白细胞样品。然后他分析了他们基因的活性——靠测量信使RNA的多少。这种分子携带着基因上的指令，告诉细胞合成那类蛋白质。在这两种人中，大多数基因的信使RNA的水平是一样的。然而有些基因在孤独之人中活力较弱，同时另外一些基因却活力较高。而且，无论是活力较高的基因还是活力较低的基因都来自少数功能群。

Broadly speaking, the genes less active in the lonely were those involved in staving off viral infections. Those that were more active were involved in protecting against bacteria. Dr Cole suspects this could help explain not only why the lonely are iller, but how, in evolutionary terms, this odd state of affairs has come about. For inflammation is an antibacterial response.
一般来说，孤独的人体内活力较低的基因是那些帮助人们避开病毒感染的基因。而那些活力较高的基因帮助人们抵抗细菌。Cole博士怀疑这不但能够解释为什么孤独之人容易得病，而且能从进化的角度这种奇怪的状态时怎么进化来的。因为炎症反应时抵抗细菌的反应。

The crucial bit of the puzzle is that viruses have to be caught from another infected individual and they are usually species-specific. Bacteria, in contrast, often just lurk in the environment (like tetanus), and may thrive on many hosts (as does bubonic plague, for example). The gregarious are therefore at greater risk than the lonely of catching viruses, and Dr Cole thus suggests that past evolution has created a mechanism (the details of which remain unclear) which causes white cells to respond appropriately. Conversely, the lonely are better off ramping up their protection against bacterial infection, which is a bigger relative risk to them.
这个问题的关键点是，病毒必须从另外一个已经感染此病毒的身上感染另一个人，并且病毒通常有其一对一的特殊宿主。细菌却相反，它们潜伏在周围环境中（像是破伤风杆菌），并且宿主众多（比如说黑死病）。因而爱交际的人比孤独之人更易感染病毒。因此Cole博士认为进化过程创造出了一种机制（细节仍不清楚），可以让白细胞对这一状况进行反应。相反，孤独之人更善于加强他们对细菌感染的保护反应，这对他们来说是一个相对更大的风险。

What Dr Cole seems to have revealed, then, is a mechanism by which the environment (in this case the social environment) reaches inside a person's body and tweaks its genome so that it responds appropriately. It is not that the lonely and the gregarious are genetically different from each other. Rather, their genes are regulated differently, according to how sociable an individual is. Dr Cole thinks this regulation is part of a wider mechanism that tunes individuals to the circumstances they find themselves in. Where it goes wrong is when loneliness becomes chronic, and the inflammatory response becomes chronic at the same time.
Cole博士想要揭示的是这样一种机制：环境（在这里是社交环境）可以影响人们体内的生化活动，调整人体内的基因组以让其做出合适的反应。并不是说孤独之人和爱交际之人在基因上彼此不同。而是他们根据个人对交际喜爱的程度不同，各自以不同的方式调控各自的基因。Cole博士认为这种调节是一种更广泛的让个人适应他们所在环境的机制中的一部分。当孤独的生活状态变成一种常态，问题就出现了——炎症反应同时也变成常态了（成了慢性疾病）。

Before civilisation intervened, such chronic loneliness would have been so rare (because isolated individuals are so vulnerable to predation) that evolution would have ignored it. Now, paradoxically, the large population that civilisation makes possible means loneliness is commonplace—and with it consequences that natural selection, which is blind to the future, has not yet had time to deal with.
在文明到来之前，这种常态性的孤独非常罕见（因为单独的个体易被捕食），进化就把它忽略了。现在，自相矛盾地，文明使得人口众多成为可能，意味着孤独状态成为常事——在这种情况下看不清未来的自然选择的后果还来不及去应付。