TED演講:曬太陽對心臟有益嗎

　　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.

　　在成為皮膚科醫(yī)生之前 我最初在一般內(nèi)科(實習) 正如英國的大多數(shù)皮膚科醫(yī)生所經(jīng)歷的那樣 在實習結(jié)束前我去了澳大利亞 那是大約20年前了。 去了澳大利亞 你就知道那里的人非常爭強好勝 他們對于獲勝可謂是斤斤計較 這類事情經(jīng)常發(fā)生： “你們英國佬不會打板球和橄欖球。” 這個我能接受

　　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."

　　但換到工作中—— 我們每周有一次期刊俱樂部的活動， 我跟別的醫(yī)生們一起坐下來 研究一篇科學論文 只要與醫(yī)學相關(guān) 第一個星期后，課題是關(guān)于心血管疾病的死亡率， 這很枯燥—— 多少人死于心臟病， 死亡率是多少。 他們就抬杠說 “你們英國佬的心臟病率令人震驚。”

　　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.

　　當然，他們沒錯 澳大利亞人的心臟病發(fā)病率比我們少三分之一 心臟病、心率衰竭、以及中風等病致死的概率也低 他們(跟英國人比)是個更健康的人群 當然他們說這是因為 澳大利人道德高尚，喜愛運動 因為他們是澳大利亞人，而我們是瘦弱的英國佬，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.

　　但是不只是澳大利亞人比英國人健康。 在英國內(nèi)部，健康也是有梯度的 這就是所謂的標準化死亡率 大致來說就是你死亡的概率 論文引用的是20年前的數(shù)據(jù) 在今天也適用 對比北緯50度以北地區(qū)的死亡率 這是南方的倫敦和周邊地區(qū) 北緯55度 這里情況不太好，是格拉斯哥 我來自愛丁堡 。更糟的是，這里也有愛丁堡 。

　　(Laughter)

　　(笑聲)

　　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.

　　是什么導致了這些地方的數(shù)據(jù)如此恐怖 在蘇格蘭南部 和英格蘭南部之間? 現(xiàn)在，我們知道愿意包括吸煙、 油炸的巧克力棒、薯片——這些都是格拉斯哥的飲食。 所有這些都是。 但這張圖是綜合考慮了 所有這些已知風險因素的 排除了吸煙，社會地位，飲食， 以及其他所有已知的危險因素的影響 這里有個空白區(qū)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.

　　現(xiàn)在，日照這個因素參與了進來 媒體有過大量關(guān)于維生素D的報道 許多人也開始關(guān)注 我們需要維生素D?，F(xiàn)在對兒童每天的攝入量有所規(guī)定。 我祖母在格拉斯哥長大 在20世紀二三十年代，佝僂病是個大問題 魚肝油被采用， 真正起到了預(yù)防佝僂病這種常見病的作用 小時候，祖母就給我吃過。 無疑，沒人會忘記魚肝油。

　　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.

　　可是有一個關(guān)聯(lián)：血液里維生素D越高的人 患心臟病和癌癥的幾率越低 有很多數(shù)據(jù)標明維生素D對人體有益。 它會預(yù)防佝僂病，等等。 但如果你給人們維生素D補充劑， 并不會改變心臟病的高發(fā)率。 它預(yù)防癌癥的證據(jù)還不太具說服力 我的想法是，維生素D不是唯一的影響因素 它不是預(yù)防心臟病的唯一原因。 維生素D高，是常曬太陽的結(jié)果 我將要說明，多曬太陽 能減少患心臟病的風險

　　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.

　　不管怎樣，我從澳大利亞回來了， 我冒著生命危險搬到了阿伯丁 (笑聲) 現(xiàn)在，在阿伯丁，我開始進行皮膚科的培訓 可我也對研究感興趣， 特別是對一氧化氮這種物質(zhì)感興趣。 這三個人 弗奇戈特、伊格納羅和穆拉德 是1998年諾貝爾醫(yī)學獎的得主 他們是最早來描述 這種新的化學傳遞物——一氧化氮——的人 一氧化氮會擴張血管， 降低血壓。 它也能擴張冠狀動脈，從而緩解心絞痛。

　　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.

　　它與眾不同的是 過去當我們想到體內(nèi)的化學信使時， 我們會想到一些復(fù)雜的諸東西，如雌激素、胰島素、 或神經(jīng)傳導。 非常復(fù)雜的流程伴有非常復(fù)雜的化學物質(zhì) 存在于非常復(fù)雜的受體中。 這是個非常簡單的分子， 一個氮和一個氧粘在一起， 但這些對我們的維持較低的血壓至關(guān)重要， 它作用于神經(jīng)傳遞和許多許多東西， 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?

　　我們開始研究，并且非常激動地發(fā)現(xiàn)， 皮膚會生成一氧化氮。 所以它不只是在心血管系統(tǒng)中才出現(xiàn) 它在皮膚上也出現(xiàn)。 將這個發(fā)現(xiàn)發(fā)表之后 我就想，它在干啥呢? 你皮膚上怎么能有低血壓呢? 不是心臟。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.

　　于是我去了美國，很多人都去美國做研究 我在匹斯堡呆了幾年，這就是匹斯堡。 我對這些超級復(fù)雜的系統(tǒng)感興趣。 我們認為也許一氧化氮影響細胞死亡， 影響細胞存活，也影響細胞的免疫 我先開始研究細胞文化，細胞生長 接著用被擊昏了的老鼠作為模特 那些老鼠不能生產(chǎn)基因。 我們研究出一個機理：一氧化氮幫助細胞存活

　　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.

　　后來我搬回愛丁堡。 在愛丁堡，我的實驗動物是醫(yī)學院學生。 是接近人類的一個物種， 跟老鼠相比有以下幾個好處： 不用付費，不用給他們剃毛，不用喂養(yǎng)他們 沒人查你的辦公室，還要說： “管好你實驗室的醫(yī)科學生。” 所以說，他們真是理想的模特。

　　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.

　　但我們發(fā)現(xiàn) 我們不能在人身上復(fù)制出在老鼠身上得到的數(shù)據(jù)。 看來我們不能停止 人體皮膚產(chǎn)生一氧化氮 我們涂上乳液就能阻擋制造它的酶， 我們能注射藥品。但我們無法停住一氧化氮。

　　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?

　　經(jīng)過兩三年的工作，我們終于找出了原因， 我們皮膚里大量儲存的并非一氧化氮 因為一氧化氮是氣體 它要揮發(fā)的——(噗!) ——幾秒鐘就沒影了， 但一氧化氮能轉(zhuǎn)化成 硝酸鹽、硝酸鹽、亞硝酸鹽、二氧化氮、亞硝基硫醇。 這些形式更穩(wěn)定 你的皮膚就得到了大量的一氧化氮 我們就尋思 陽光是否會活化這大量的一氧化氮 將它們從皮膚中釋放出來 這些一氧化氮的存量10倍于參與新陳代謝的一氧化氮量 太陽能不能激活這些存量讓它們參與新陳代謝， 從而作用于心血管系統(tǒng)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，是個實驗皮膚科醫(yī)生， 所以我們想到 應(yīng)該讓實驗動物多曬太陽 于是，我們找來了一群志愿者 讓他們接受紫外線照射 這些是太陽燈。 這里我們要小心 維生素D是通過中波紫外線(UVB)射線生成的 而我們想排除維生素D的干擾 所以，我們使用了不生成維生素D的長波紫外線(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.

　　我們對受試者進行照射 強度相當于暴露在愛丁堡夏日陽光中30分鐘 結(jié)果是我們得到了 新陳代謝中一氧化氮的提升 我們讓心血管病的患者接受紫外線照射 他們的一氧化氮水平上升了 而他們的血壓下降了 就個人而言不算多 但對于整個人群而言有顯著意義 足以改變整個人群的心臟病患病率 給他們照射紫外線 或者使他們的皮膚太陽燈的溫度那樣溫暖 但不讓光線接觸皮膚，同樣的結(jié)果就不會發(fā)生 這似乎說明了其中關(guān)鍵在于紫外線要接觸到皮膚

　　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.

　　我們至今仍在收集數(shù)據(jù) 有幾樣好的發(fā)現(xiàn)： 這在年長者身上效果更明顯 我不確定具體的數(shù)量 其中一個被試是我的岳母大人 很顯然我不太清楚她的年齡 但肯定比我太太年紀要大 在她身上效果更明顯 我要提到的另一點是 在整個過程中維生素D并沒有發(fā)生變化 維生素D的影響是被分離的 維生素D對人有益——它預(yù)防佝僂病 還能預(yù)防鈣流失，是很重要的微量元素 但(我們研究的)這是一個與維生素D相分離的機制

　　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.

　　現(xiàn)今在血壓的問題上有一點要注意 就是你的身體會竭盡所能 去把血壓維持在同一個水平 如果你的腿被剁斷，你會失血， 你的身體會施加壓力，增加心跳， 來盡可能地維持你的正常血壓。 這是一個絕對的基本生理原則。

　　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.

　　所以我們接下來做的 就是轉(zhuǎn)而研究血管擴張 我們測試了同一批(實驗動物) 注意他們沒有尾巴也沒有皮毛，這是個醫(yī)科學生。 你測量手臂上的血流 測量血流通過時血管擴張了多少 這里顯示的是在做假射機 這里有條粗線 紫外線照射到手臂上，皮膚升溫 但我們蓋住皮膚，所以紫外線就接觸不到了 血流量沒有變化，血管也沒有擴張 但如果讓紫外線接觸皮膚 在紫外線照射期間及照射后一小時 血管都有所擴張 這就是降低血壓的機制 你的冠狀動脈也擴張了 給心臟提供更多的血液 這里有更多有關(guān)紫外線——也就是太陽光的作用 數(shù)據(jù)顯示紫外線有益于血流和心血管系統(tǒng)。

　　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.

　　我們認為我們只是一種模型-- 不同時節(jié)照射到不同地域的紫外線是不等的 所以，你其實可以 將皮膚里的硝酸鹽、亞硝酸鹽、還有亞硝基硫醇 分解得到一氧化氮 不同波長的光產(chǎn)生不同的反應(yīng) 所以你可以去檢視光波 如果你住在赤道地區(qū)，太陽光垂直射入 薄薄的大氣 無論冬夏，光照的量是相同的 如果你住在(高緯度地區(qū)) 太陽光在夏季幾乎是直射的 而在冬季就會斜穿厚厚的大氣 很多紫外線無法到達地面 而到達地面的波長范圍 夏天和冬天是不同的 你可以把這些數(shù)據(jù) 乘上一氧化氮的釋放量 你就可以算出有多少一氧化氮 從皮膚里釋放，參與到新陳代謝中去

　　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.

　　如果你在赤道地區(qū) 也就是這兩條紅色和紫色的線 線下方的區(qū)域代表一氧化氮的釋放量 也就是這片區(qū)域 所以如果你在赤道地區(qū)，不管是12月份還是6月份 你的皮膚里都能釋放大量的一氧化氮 南加州有個地方叫文圖拉 你在夏天能得到相當于赤道地區(qū)的日照 這太棒了，釋放了很多的一氧化氮 文圖拉的隆冬，結(jié)果也不錯 愛丁堡的夏季，曲線以下的區(qū)域也還行 可以一到冬季，一氧化氮 幾乎就不釋放了

　　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.

　　我們?nèi)绾慰创@個結(jié)果? 我們?nèi)匀辉谘芯?我們?nèi)匀辉诎l(fā)掘和擴展 我們認為這項研究非常重要 我們認為這項研究能解釋英國南北部很多的健康問題的差異 這是與我們切實相關(guān)的 我們認為人的皮膚 我們知道人的皮膚上有很多 以不同形式存在的一氧化氮 我們猜想其中有很多來自于飲食 綠葉蔬菜，甜菜根、還有生菜 含有很多的一氧化氮，我們認為它最終來到皮膚 并且貯存在皮膚里 我們認為太陽光能釋放這些一氧化氮 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?

　　這個研究還在進行之中，可皮膚科醫(yī)生們—— 我就是一名皮膚科醫(yī)生 白天的工作中我要對病人說，“你得了皮膚癌， 是陽光引起的， 別去曬太陽。” 其實我認為還有更重要的一則訊息 就是曬太陽既有益處，也有風險 沒錯，陽光是引發(fā)皮膚癌的一個主要風險變量 但是死于心臟病的人數(shù) 是死于皮膚癌的一百倍 我們需要加深對此的了解 我們還需要找到其中的風險效益比 曬多少太陽是安全的? 如何掌握其中分寸來增進大家普遍的健康?

　　So, thank you very much indeed.