健康革命 人類最大的福祉

The highest life expectancy recorded for women anywhere in the world has risen by a year every four years since 1840. This inexorable advance in longevity is, arguably, the most important of all the changes to human life in the past two centuries.

自從1840年以來，全球女性預期壽命的最高紀錄每四年就增加一歲。人類在延長自身壽命方面的這種持續不斷的進步，也許就是過去兩個世紀人類生活所有變化中最重大的變化。

These gains in health are also widely shared: “India today has a higher life expectancy than Scotland in 1945 — in spite of a per-capita income that Britain had achieved as early as 1860.” This remark comes from a wonderful book, The Great Escape: Health, Wealth, and the Origins of Inequality, by Princeton University’s Angus Deaton, published last year, which documents the revolution in both health and wealth since the early 19th century. Of the two, the former is the more important. Who would not give up many material comforts if, in return, they could avoid the agony of watching their children die or enjoy the company of their loved ones in old age?

人類健康方面的進步也具有廣泛性：“今日印度人的預期壽命高於1945年的蘇格蘭人，儘管在人均收入方面，英國早在1860年就達到了印度今日的水平。”這句話出自去年出版的一本精彩著作：《逃離不平等：健康、財富及不平等的起源》(The Great Escape: Health, Wealth, and the Origins of Inequality)，作者是美國普林斯頓大學(Princeton University)的安格斯•狄頓(Angus Deaton)，書裏講述了自19世紀初以來人類健康和財富方面發生的革命。在這二者之中，前者更加重要。如果能夠避免目睹孩子死去的悲痛，或者能夠享有長壽父母的陪伴，誰不願放棄更多物質享受來交換呢？

No blessing is unmixed. Prolonged survival “sans teeth, sans eyes, sans taste, sans everything” is to be neither envied nor desired. Yet the revolution in health is still a blessing. As Professor Deaton notes: “Of all the things that make life worth living, extra years of life are surely among the most precious.” Someone whose standard of living is twice as high and expects to live twice as long as someone else could even be deemed to be four times better off.

任何好事都不是純粹的。延長“沒有牙齒、沒有視力，沒有味覺，沒有一切”的殘生既不值得羨慕也不令人期望。然而健康革命仍是人類一大福祉。正如狄頓教授所說：“在所有讓生活有價值的事物中，多活幾年肯定屬於最珍貴的那一類。”有些人生活水平高出常人一倍，並且預計要比別人多活一倍時間，人們大概可以認爲，他們比常人幸福四倍。

So what has happened?

那麼，人類的健康都發生了哪些變化呢？

Start with mortality rates (deaths per thousands) over time of three of today’s high-income countries: Sweden in 1751; the US in 1933; and the Netherlands and the US in 2000 (see chart). Back in 1751 the mortality rate of Swedish newborns was more than 160 per thousand people. It was more than 40 per thousand in the US in 1933. By 2000 it was below 10 per thousand. At subsequent ages mortality rates have become consistently lower over time, with the lowest rates of all for children aged about 10. Today we see a rise of mortality rates in the late teens, largely because of the riskier behaviour of young men. After a plateau in the late 20s and early 30s, death rates rise, but they do not reach 10 per thousand before age 60. US mortality rates are higher than those in the Netherlands, except for the over 80s. That is where the US concentrates its resources.

首先來看看當今三個高收入國家人口死亡率（每千人死亡人數）不同年份的情況：1751年的瑞典，1933年的美國，以及2000年的荷蘭和美國（見右圖）。1751年瑞典新生兒死亡率超過160人/千人。1933年美國新生兒死亡率超過40人/千人，到了2000年低於10人/千人。各年齡段兒童死亡率均在不斷降低，其中10歲左右的兒童死亡率最低。我們看到較大年齡的少年死亡率現在有所上升，大部分是因爲男孩子們的危險行爲。在三十歲左右的年齡段經歷了一段平臺期後，死亡率又開始上升，但60歲以下死亡率不足10人/千人。美國的死亡率比荷蘭的高，但80歲以上年齡段例外，美國的醫療資源主要集中在這一年齡段中。

Back in 1850 life expectancy was about age 40 in England and Wales. Today it is close to 80. In the case of Italy it has risen from 30 in 1875 to above the English level. The chart also shows the devastating effects of the Spanish flu epidemic of 1918. This is explained by how life expectancy is computed: the assumption is that the risks of dying at a particular age are produced by the ages of death of the population in a specific year. In 1918 a large proportion of young people died in the epidemic. This reduced life expectancy drastically. But those born in 1918 had far longer lives than these figures suggest. Similarly, a small proportion of the English and Welsh population actually died at 40 in 1850. Instead, a great many died aged as babies and many lived to be more than 60. Forty was merely the average age of death. Finally, notes Prof Deaton: “Saving the lives of children has a bigger effect on life expectancy than saving the lives of the elderly.” Thus, as death “ages”, the rise in life expectancy slows.

1850年英格蘭和威爾士的人口預期壽命在40歲左右，如今已接近80歲。意大利的人口預期壽命從1875年的30歲一路上升，直到高於英國水平。圖表還顯示了1918年西班牙流感的災難性後果。這可以從預期壽命的計算方法得到解釋，它假設某個年齡的死亡風險是由某年人口死亡年齡來決定的。1918年有很大一部分比例的年輕人死於西班牙流感，導致預期壽命大大降低。但1918年出生的人壽命遠高於圖表所顯示的年齡。同樣地，1850年英格蘭和威爾士實際上只有一小部分人死於40歲，死亡人口中有許多是嬰兒。還有很多人活到了60歲以上，40歲只是平均死亡年齡。最後，狄頓教授指出：“在提高預期壽命方面，拯救兒童生命的作用遠大於拯救老年人生命。”因此，隨着死亡年齡提高，預期壽命上升減緩。

The health revolution has spread worldwide since the middle of the 20th century — dramatically so in east Asia; least so, alas, in sub-Saharan Africa partly because of HIV/Aids. A big element has been the collapse in child mortality. According to the Gapminder website, mortality among Indian children under five fell from 267 per thousand in 1950 to 56 in 2012. Over the same period it fell from 317 to 14 in China. These improvements occurred at much lower income levels than was the case in today’s high-income countries. This is partly because of improved knowledge (oral rehydration, for example), partly because of medical technology (vaccination, for example) and partly because of public services (clean water and sanitation, for example).

健康革命自20世紀中葉起席捲了全球，東亞地區變化尤爲劇烈，撒哈拉以南非洲地區變化最小，原因在於艾滋病毒/艾滋病(HIV/Aids)。兒童死亡率大幅下降佔了很大因素。根據Gapminder網站的數據，印度5歲以下兒童死亡率從1950年的267人/千人下降到2012年的56人/千人。同時期中國的這一指標從317人/千人下降到14人/千人。這些進步發生在那些收入水平較低的國家，而不是現在的高收入國家。一部分原因在於知識水平提高（如口服補液），一部分原因在於醫療技術（如接種疫苗），還有部分原因在於公共服務（如潔淨水和衛生設施）。

Unfortunately, the improvements are not as complete as they should be. In Angola the under-five mortality rate is 164 per thousand. In Nigeria it is 124. Yet these are relatively well-off countries. In general, a link exists between prosperity and health. Yet greater prosperity is neither a necessary nor a sufficient condition for improved health outcomes. It just makes it rather easier.

遺憾的是，這種改善還沒有達到應有的普及程度。在安哥拉，5歲以下嬰幼兒死亡率爲千分之164。在尼日利亞，這個數字爲千分之124。不過，這些還是相對富裕的國家。一般而言，富裕程度和健康狀況存在關聯。然而，富裕程度更高既非健康狀況改善的必要條件，也非其充分條件。前者只不過使得後者更容易實現。

The health revolution is not just a good in itself. It has beneficial consequences, the most important of which is the transformation of women’s lives. As child mortality tumbles, so does fertility: fewer births are needed to achieve a given family size. This is irrespective of religion: in Muslim Iran, for example, the number of children per woman fell from 6.5 in 1980 to 1.9 in 2012; similarly, in Catholic Brazil it fell from 6.2 in 1960 to 1.8 in 2012. As women live longer and have fewer children, they can invest more in each child and pursue their own careers. Thus the health revolution underpins another of the revolutions of our era: the change in the role of women.

健康革命的好處並不僅限於改善健康狀況本身。它帶來多種好處，其中最重要的一點是改變了女性的生活。隨着兒童死亡率大幅下跌，生育率也大幅下降：創建一定規模的家庭所需生育的孩子減少了。這種現象不受宗教影響：比如，在信仰伊斯蘭教的伊朗，每個女性生育的孩子的數量，從1980年的6.5個降至2012年的1.9個；類似的，在信仰天主教的巴西，這個數字從1960年的6.2個降至2012年的1.8個。隨着女性壽命延長、生育孩子的數量減少，她們可以在每個孩子身上投入的更多，也可以追求自己的事業。因此，健康革命支撐了我們這個時代的另一場革命：女性角色的改變。

What has driven the improvements in health, particularly among the middle aged? A decline in smoking is a factor. Improved treatment for heart disease is another. Even cancer is succumbing to treatment. Increasingly, in high-income countries, the remaining diseases are those of old age, including dementia. But in most developing countries the old afflictions linger, including poor sanitation, contaminated water and malaria.

健康狀況改善的主要驅動因素是什麼，尤其是在中年人中間？吸菸人數減少是一個因素。心臟病治療水平提高則是另外一個因素。就連癌症也不再是不治之症。在高收入國家，老年病（包括老年癡呆症）在剩下的疾病中佔比越來越高。但在大多數發展中國家，各種老問題依然存在，包括公共衛生狀況差、水污染、以及瘧疾。

Yet for all that remains to be done, and all the inequality of health services across the globe, it is important to appreciate the great and increasingly widely shared improvement in health. An increasing proportion of humanity has a good chance of living healthily into what has traditionally been viewed as old age. A rising proportion of children is reaching maturity. We cannot escape death. But we do keep out of its grasp for ever longer. That is to be celebrated.

儘管仍然存在種種需要解決的問題，世界各地的醫療服務仍然發展不均，但非常重要的一點是，要認識到人類健康狀況出現了巨大的改善，而且這種改善覆蓋到越來越多的人。越來越多的人有很大機會以健康的身體步入傳統觀點中的老年期。成年前夭折的兒童比率越來越低。死亡是無法逃避的。但我們在被死神抓住之前的生存時間比以往任何時候都更長了。這是值得慶祝的。