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TED演讲:晒太阳对心脏有益吗

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2016年05月16日

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  So, before I became a dermatologist, I started in general medicine, as most dermatologists do in Britain. At the end of that time, I went off to Australia, about 20 years ago. What you learn when you go to Australia is the Australians are very competitive. And they are not magnanimous in victory. And that happened a lot: "You pommies, you can't play cricket, rugby." I could accept that.

  在成为皮肤科医生之前 我最初在一般内科(实习) 正如英国的大多数皮肤科医生所经历的那样 在实习结束前我去了澳大利亚 那是大约20年前了。 去了澳大利亚 你就知道那里的人非常争强好胜 他们对于获胜可谓是斤斤计较 这类事情经常发生: “你们英国佬不会打板球和橄榄球。” 这个我能接受

  But moving into work -- and we have each week what's called a journal club, when you'd sit down with the other doctors and you'd study a scientific paper in relation to medicine. And after week one, it was about cardiovascular mortality, a dry subject -- how many people die of heart disease, what the rates are. And they were competitive about this: "You pommies, your rates of heart disease are shocking."

  但换到工作中—— 我们每周有一次期刊俱乐部的活动, 我跟别的医生们一起坐下来 研究一篇科学论文 只要与医学相关 第一个星期后,课题是关于心血管疾病的死亡率, 这很枯燥—— 多少人死于心脏病, 死亡率是多少。 他们就抬杠说 “你们英国佬的心脏病率令人震惊。”

  And of course, they were right. Australians have about a third less heart disease than we do -- less deaths from heart attacks, heart failure, less strokes -- they're generally a healthier bunch. And of course they said this was because of their fine moral standing, their exercise, because they're Australians and we're weedy pommies, and so on.

  当然,他们没错 澳大利亚人的心脏病发病率比我们少三分之一 心脏病、心率衰竭、以及中风等病致死的概率也低 他们(跟英国人比)是个更健康的人群 当然他们说这是因为 澳大利人道德高尚,喜爱运动 因为他们是澳大利亚人,而我们是瘦弱的英国佬,等等。

  But it's not just Australia that has better health than Britain. Within Britain, there is a gradient of health -- and this is what's called standardized mortality, basically your chances of dying. This is looking at data from the paper about 20 years ago, but it's true today. Comparing your rates of dying 50 degrees north -- that's the South, that's London and places -- by latitude, and 55 degrees -- the bad news is that's here, Glasgow. I'm from Edinburgh. Worse news, that's even Edinburgh.

  但是不只是澳大利亚人比英国人健康。 在英国内部,健康也是有梯度的 这就是所谓的标准化死亡率 大致来说就是你死亡的概率 论文引用的是20年前的数据 在今天也适用 对比北纬50度以北地区的死亡率 这是南方的伦敦和周边地区 北纬55度 这里情况不太好,是格拉斯哥 我来自爱丁堡 。更糟的是,这里也有爱丁堡 。

  (Laughter)

  (笑声)

  So what accounts for this horrible space here between us up here in southern Scotland and the South? Now, we know about smoking, deep-fried Mars bars, chips -- the Glasgow diet. All of these things. But this graph is after taking into account all of these known risk factors. This is after accounting for smoking, social class, diet, all those other known risk factors. We are left with this missing space of increased deaths the further north you go.

  是什么导致了这些地方的数据如此恐怖 在苏格兰南部 和英格兰南部之间? 现在,我们知道愿意包括吸烟、 油炸的巧克力棒、薯片——这些都是格拉斯哥的饮食。 所有这些都是。 但这张图是综合考虑了 所有这些已知风险因素的 排除了吸烟,社会地位,饮食, 以及其他所有已知的危险因素的影响 这里有个空白区域 越往北,死亡率越高

  Now, sunlight, of course, comes into this. And vitamin D has had a great deal of press, and a lot of people get concerned about it. And we need vitamin D. It's now a requirement that children have a certain amount. My grandmother grew up in Glasgow, back in the 1920s and '30s when rickets was a real problem and cod liver oil was brought in. And that really prevented the rickets that used to be common in this city. And I as a child was fed cod liver oil by my grandmother. I distinctly -- nobody forgets cod liver oil.

  现在,日照这个因素参与了进来 媒体有过大量关于维生素D的报道 许多人也开始关注 我们需要维生素D。现在对儿童每天的摄入量有所规定。 我祖母在格拉斯哥长大 在20世纪二三十年代,佝偻病是个大问题 鱼肝油被采用, 真正起到了预防佝偻病这种常见病的作用 小时候,祖母就给我吃过。 无疑,没人会忘记鱼肝油。

  But an association: The higher people's blood levels of vitamin D are, the less heart disease they have, the less cancer. There seems to be a lot of data suggesting that vitamin D is very good for you. And it is, to prevent rickets and so on. But if you give people vitamin D supplements, you don't change that high rate of heart disease. And the evidence for it preventing cancers is not yet great. So what I'm going to suggest is that vitamin D is not the only story in town. It's not the only reason preventing heart disease. High vitamin D levels, I think, are a marker for sunlight exposure, and sunlight exposure, in methods I'm going to show, is good for heart disease.

  可是有一个关联:血液里维生素D越高的人 患心脏病和癌症的几率越低 有很多数据标明维生素D对人体有益。 它会预防佝偻病,等等。 但如果你给人们维生素D补充剂, 并不会改变心脏病的高发率。 它预防癌症的证据还不太具说服力 我的想法是,维生素D不是唯一的影响因素 它不是预防心脏病的唯一原因。 维生素D高,是常晒太阳的结果 我将要说明,多晒太阳 能减少患心脏病的风险

  Anyway, I came back from Australia, and despite the obvious risks to my health, I moved to Aberdeen. (Laughter) Now, in Aberdeen, I started my dermatology training. But I also became interested in research, and in particular I became interested in this substance, nitric oxide. Now these three guys up here, Furchgott, Ignarro and Murad, won the Nobel Prize for medicine back in 1998. And they were the first people to describe this new chemical transmitter, nitric oxide. What nitric oxide does is it dilates blood vessels, so it lowers your blood pressure. It also dilates the coronary arteries, so it stops angina.

  不管怎样,我从澳大利亚回来了, 我冒着生命危险搬到了阿伯丁 (笑声) 现在,在阿伯丁,我开始进行皮肤科的培训 可我也对研究感兴趣, 特别是对一氧化氮这种物质感兴趣。 这三个人 弗奇戈特、伊格纳罗和穆拉德 是1998年诺贝尔医学奖的得主 他们是最早来描述 这种新的化学传递物——一氧化氮——的人 一氧化氮会扩张血管, 降低血压。 它也能扩张冠状动脉,从而缓解心绞痛。

  And what was remarkable about it was in the past when we think of chemical messengers within the body, we thought of complicated things like estrogen and insulin, or nerve transmission. Very complex processes with very complex chemicals that fit into very complex receptors. And here's this incredibly simple molecule, a nitrogen and an oxygen that are stuck together, and yet these are hugely important for [unclear] our low blood pressure, for neurotransmission, for many, many things, but particularly cardiovascular health.

  它与众不同的是 过去当我们想到体内的化学信使时, 我们会想到一些复杂的诸东西,如雌激素、胰岛素、 或神经传导。 非常复杂的流程伴有非常复杂的化学物质 存在于非常复杂的受体中。 这是个非常简单的分子, 一个氮和一个氧粘在一起, 但这些对我们的维持较低的血压至关重要, 它作用于神经传递和许多许多东西, 尤其是心血管健康。

  And I started doing research, and we found, very excitingly, that the skin produces nitric oxide. So it's not just in the cardiovascular system it arises. It arises in the skin. Well, having found that and published that, I thought, well, what's it doing? How do you have low blood pressure in your skin? It's not the heart. What do you do?

  我们开始研究,并且非常激动地发现, 皮肤会生成一氧化氮。 所以它不只是在心血管系统中才出现 它在皮肤上也出现。 将这个发现发表之后 我就想,它在干啥呢? 你皮肤上怎么能有低血压呢? 不是心脏。你是干啥呢?

  So I went off to the States, as many people do if they're going to do research, and I spent a few years in Pittsburgh. This is Pittsburgh. And I was interested in these really complex systems. We thought that maybe nitric oxide affected cell death, and how cells survive, and their resistance to other things. And I first off started work in cell culture, growing cells, and then I was using knockout mouse models -- mice that couldn't make the gene. We worked out a mechanism, which -- NO was helping cells survive.

  于是我去了美国,很多人都去美国做研究 我在匹斯堡呆了几年,这就是匹斯堡。 我对这些超级复杂的系统感兴趣。 我们认为也许一氧化氮影响细胞死亡, 影响细胞存活,也影响细胞的免疫 我先开始研究细胞文化,细胞生长 接着用被击昏了的老鼠作为模特 那些老鼠不能生产基因。 我们研究出一个机理:一氧化氮帮助细胞存活

  And I then moved back to Edinburgh. And in Edinburgh, the experimental animal we use is the medical student. It's a species close to human, with several advantages over mice: They're free, you don't shave them, they feed themselves, and nobody pickets your office saying, "Save the lab medical student." So they're really an ideal model.

  后来我搬回爱丁堡。 在爱丁堡,我的实验动物是医学院学生。 是接近人类的一个物种, 跟老鼠相比有以下几个好处: 不用付费,不用给他们剃毛,不用喂养他们 没人查你的办公室,还要说: “管好你实验室的医科学生。” 所以说,他们真是理想的模特。

  But what we found was that we couldn't reproduce in man the data we had shown in mice. It seemed we couldn't turn off the production of nitric oxide in the skin of humans. We put on creams that blocked the enzyme that made it, we injected things. We couldn't turn off the nitric oxide.

  但我们发现 我们不能在人身上复制出在老鼠身上得到的数据。 看来我们不能停止 人体皮肤产生一氧化氮 我们涂上乳液就能阻挡制造它的酶, 我们能注射药品。但我们无法停住一氧化氮。

  And the reason for this, it turned out, after two or three years' work, was that in the skin we have huge stores not of nitric oxide, because nitric oxide is a gas, and it's released -- (Poof!) -- and in a few seconds it's away, but it can be turned into these forms of nitric oxide -- nitrate, NO3; nitrite, NO2; nitrosothiols. And these are more stable, and your skin has got really large stores of NO. And we then thought to ourselves, with those big stores, I wonder if sunlight might activate those stores and release them from the skin, where the stores are about 10 times as big as what's in the circulation. Could the sun activate those stores into the circulation, and there in the circulation do its good things for your cardiovascular system?

  经过两三年的工作,我们终于找出了原因, 我们皮肤里大量储存的并非一氧化氮 因为一氧化氮是气体 它要挥发的——(噗!) ——几秒钟就没影了, 但一氧化氮能转化成 硝酸盐、硝酸盐、亚硝酸盐、二氧化氮、亚硝基硫醇。 这些形式更稳定 你的皮肤就得到了大量的一氧化氮 我们就寻思 阳光是否会活化这大量的一氧化氮 将它们从皮肤中释放出来 这些一氧化氮的存量10倍于参与新陈代谢的一氧化氮量 太阳能不能激活这些存量让它们参与新陈代谢, 从而作用于心血管系统呢?

  Well, I'm an experimental dermatologist, so what we did was we thought we'd have to expose our experimental animals to sunlight. And so what we did was we took a bunch of volunteers and we exposed them to ultraviolet light. So these are kind of sunlamps. Now, what we were careful to do was, vitamin D is made by ultraviolet B rays and we wanted to separate our story from the vitamin D story. So we used ultraviolet A, which doesn't make vitamin D.

  我呢,是个实验皮肤科医生, 所以我们想到 应该让实验动物多晒太阳 于是,我们找来了一群志愿者 让他们接受紫外线照射 这些是太阳灯。 这里我们要小心 维生素D是通过中波紫外线(UVB)射线生成的 而我们想排除维生素D的干扰 所以,我们使用了不生成维生素D的长波紫外线(UVA)

  When we put people under a lamp for the equivalent of about 30 minutes of sunshine in summer in Edinburgh, what we produced was, we produced a rise in circulating nitric oxide. So we put patients with these subjects under the UV, and their NO levels do go up, and their blood pressure goes down. Not by much, as an individual level, but enough at a population level to shift the rates of heart disease in a whole population. And when we shone UV at them, or when we warmed them up to the same level as the lamps, but didn't actually let the rays hit the skin, this didn't happen. So this seems to be a feature of ultraviolet rays hitting the skin.

  我们对受试者进行照射 强度相当于暴露在爱丁堡夏日阳光中30分钟 结果是我们得到了 新陈代谢中一氧化氮的提升 我们让心血管病的患者接受紫外线照射 他们的一氧化氮水平上升了 而他们的血压下降了 就个人而言不算多 但对于整个人群而言有显著意义 足以改变整个人群的心脏病患病率 给他们照射紫外线 或者使他们的皮肤太阳灯的温度那样温暖 但不让光线接触皮肤,同样的结果就不会发生 这似乎说明了其中关键在于紫外线要接触到皮肤

  Now, we're still collecting data. A few good things here: This appeared to be more marked in older people. I'm not sure exactly how much. One of the subjects here was my mother-in-law, and clearly I do not know her age. But certainly in people older than my wife, this appears to be a more marked effect. And the other thing I should mention was there was no change in vitamin D. This is separate from vitamin D. So vitamin D is good for you -- it stops rickets, it prevents calcium metabolism, important stuff. But this is a separate mechanism from vitamin D.

  我们至今仍在收集数据 有几样好的发现: 这在年长者身上效果更明显 我不确定具体的数量 其中一个被试是我的岳母大人 很显然我不太清楚她的年龄 但肯定比我太太年纪要大 在她身上效果更明显 我要提到的另一点是 在整个过程中维生素D并没有发生变化 维生素D的影响是被分离的 维生素D对人有益——它预防佝偻病 还能预防钙流失,是很重要的微量元素 但(我们研究的)这是一个与维生素D相分离的机制

  Now, one of the problems with looking at blood pressure is your body does everything it can to keep your blood pressure at the same place. If your leg is chopped off and you lose blood, your body will clamp down, increase the heart rate, do everything it can to keep your blood pressure up. That is an absolutely fundamental physiological principle.

  现今在血压的问题上有一点要注意 就是你的身体会竭尽所能 去把血压维持在同一个水平 如果你的腿被剁断,你会失血, 你的身体会施加压力,增加心跳, 来尽可能地维持你的正常血压。 这是一个绝对的基本生理原则。

  So what we've next done is we've moved on to looking at blood vessel dilatation. So we've measured -- this is again, notice no tail and hairless, this is a medical student. In the arm, you can measure blood flow in the arm by how much it swells up as some blood flows into it. And what we've shown is that doing a sham irradiation -- this is the thick line here -- this is shining UV on the arm so it warms up but keeping it covered so the rays don't hit the skin. There is no change in blood flow, in dilatation of the blood vessels. But the active irradiation, during the UV and for an hour after it, there is dilation of the blood vessels. This is the mechanism by which you lower blood pressure, by which you dilate the coronary arteries also, to let the blood be supplied with the heart. So here, further data that ultraviolet -- that's sunlight -- has benefits on the blood flow and the cardiovascular system.

  所以我们接下来做的 就是转而研究血管扩张 我们测试了同一批(实验动物) 注意他们没有尾巴也没有皮毛,这是个医科学生。 你测量手臂上的血流 测量血流通过时血管扩张了多少 这里显示的是在做假射机 这里有条粗线 紫外线照射到手臂上,皮肤升温 但我们盖住皮肤,所以紫外线就接触不到了 血流量没有变化,血管也没有扩张 但如果让紫外线接触皮肤 在紫外线照射期间及照射后一小时 血管都有所扩张 这就是降低血压的机制 你的冠状动脉也扩张了 给心脏提供更多的血液 这里有更多有关紫外线——也就是太阳光的作用 数据显示紫外线有益于血流和心血管系统。

  So we thought we'd just kind of model -- Different amounts of UV hit different parts of the Earth at different times of year, so you can actually work out those stores of nitric oxide -- the nitrates, nitrites, nitrosothiols in the skin -- cleave to release NO. Different wavelengths of light have different activities of doing that. So you can look at the wavelengths of light that do that. And you can look -- So, if you live on the equator, the sun comes straight overhead, it comes through a very thin bit of atmosphere. In winter or summer, it's the same amount of light. If you live up here, in summer the sun is coming fairly directly down, but in winter it's coming through a huge amount of atmosphere, and much of the ultraviolet is weeded out, and the range of wavelengths that hit the Earth are different from summer to winter. So what you can do is you can multiply those data by the NO that's released and you can calculate how much nitric oxide would be released from the skin into the circulation.

  我们认为我们只是一种模型-- 不同时节照射到不同地域的紫外线是不等的 所以,你其实可以 将皮肤里的硝酸盐、亚硝酸盐、还有亚硝基硫醇 分解得到一氧化氮 不同波长的光产生不同的反应 所以你可以去检视光波 如果你住在赤道地区,太阳光垂直射入 薄薄的大气 无论冬夏,光照的量是相同的 如果你住在(高纬度地区) 太阳光在夏季几乎是直射的 而在冬季就会斜穿厚厚的大气 很多紫外线无法到达地面 而到达地面的波长范围 夏天和冬天是不同的 你可以把这些数据 乘上一氧化氮的释放量 你就可以算出有多少一氧化氮 从皮肤里释放,参与到新陈代谢中去

  Now, if you're on the equator here -- that's these two lines here, the red line and the purple line -- the amount of nitric oxide that's released is the area under the curve, it's the area in this space here. So if you're on the equator, December or June, you've got masses of NO being released from the skin. So Ventura is in southern California. In summer, you might as well be at the equator. It's great. Lots of NO is released. Ventura mid-winter, well, there's still a decent amount. Edinburgh in summer, the area beneath the curve is pretty good, but Edinburgh in winter, the amount of NO that can be released is next to nothing, tiny amounts.

  如果你在赤道地区 也就是这两条红色和紫色的线 线下方的区域代表一氧化氮的释放量 也就是这片区域 所以如果你在赤道地区,不管是12月份还是6月份 你的皮肤里都能释放大量的一氧化氮 南加州有个地方叫文图拉 你在夏天能得到相当于赤道地区的日照 这太棒了,释放了很多的一氧化氮 文图拉的隆冬,结果也不错 爱丁堡的夏季,曲线以下的区域也还行 可以一到冬季,一氧化氮 几乎就不释放了

  So what do we think? We're still working at this story, we're still developing it, we're still expanding it. We think it's very important. We think it probably accounts for a lot of the north-south health divide within Britain, It's of relevance to us. We think that the skin -- well, we know that the skin has got very large stores of nitric oxide as these various other forms. We suspect a lot of these come from diet, green leafy vegetables, beetroot, lettuce has a lot of these nitric oxides that we think go to the skin. We think they're then stored in the skin, and we think the sunlight releases this where it has generally beneficial effects.

  我们如何看待这个结果? 我们仍然在研究 我们仍然在发掘和扩展 我们认为这项研究非常重要 我们认为这项研究能解释英国南北部很多的健康问题的差异 这是与我们切实相关的 我们认为人的皮肤 我们知道人的皮肤上有很多 以不同形式存在的一氧化氮 我们猜想其中有很多来自于饮食 绿叶蔬菜,甜菜根、还有生菜 含有很多的一氧化氮,我们认为它最终来到皮肤 并且贮存在皮肤里 我们认为太阳光能释放这些一氧化氮 起到很多有益的作用

  And this is ongoing work, but dermatologists -- I mean, I'm a dermatologist. My day job is saying to people, "You've got skin cancer, it's caused by sunlight, don't go in the sun." I actually think a far more important message is that there are benefits as well as risks to sunlight. Yes, sunlight is the major alterable risk factor for skin cancer, but deaths from heart disease are a hundred times higher than deaths from skin cancer. And I think that we need to be more aware of, and we need to find the risk-benefit ratio. How much sunlight is safe, and how can we finesse this best for our general health?

  这个研究还在进行之中,可皮肤科医生们—— 我就是一名皮肤科医生 白天的工作中我要对病人说,“你得了皮肤癌, 是阳光引起的, 别去晒太阳。” 其实我认为还有更重要的一则讯息 就是晒太阳既有益处,也有风险 没错,阳光是引发皮肤癌的一个主要风险变量 但是死于心脏病的人数 是死于皮肤癌的一百倍 我们需要加深对此的了解 我们还需要找到其中的风险效益比 晒多少太阳是安全的? 如何掌握其中分寸来增进大家普遍的健康?

  So, thank you very much indeed.


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