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锁定非传染性疾病主要死因,挽救更多生命!

来源:worldhealthorg    发布时间:2019-05-13 20:48:45
关于非传染性疾病,你了解多少?
近期,牛津大学医学统计学和流行病学教授Richard Peto教授就非传染性疾病问题接受了《世界卫生组织简报》的采访,并表示:为努力减少非传染性疾病造成的过早死亡,应该集中处理主要死因

Richard Peto教授
Richard Peto自1992年以来担任牛津大学医学统计学和流行病学教授。他是很有影响力的卫生统计学家,曾与他人一道主持许多大型治疗实验、流行病学研究和荟萃分析。

他于1965年获得剑桥大学自然科学学士学位,1967年获得伦敦大学统计学硕士学位。

采访内容如下:

1
您在校时曾想做天文学家。您怎么会对医学统计产生兴趣的呢?


纯属偶然。我在大学里修了统计学课程,但实际上当时我对统计学迷迷糊糊的。后来,我于1967年去Richard Doll (1912–2005)那里面试。他是发现吸烟导致肺癌的学者之一。


面试快结束时,他问我为什么想到他那里从事统计工作,我说:“我可不知道我是否真想到你那里做统计工作, 事实上,我甚至都不知道我是否想要工作”。我记得他太太在当年圣诞晚会上对我说:“你就是那个不知道是否想要工作的年轻人吧。你现在拿定主意了吗?”我说我还没有。当时我不能确定每天上班就是天底下最棒的事情。

2
您后来为什么改变主意呢?

几个月后,我开始有了第一批科学成果。那些成果实际上是否重要并不要紧,但获得新成果确实很有意思和令人兴奋。从那时起,我越来越埋头工作。头几个月,我绝不把工作带回家做。而现在,我总是带着公文包回家。不过,我年轻时的生活可能更精彩些。

3
您当年从事什么样研究?

我做许多不同的研究项目,其中有两个项目与烟草特别相关。Charles Fletcher(1911-1995)是皇家医学院1962年吸烟危害专题报告的撰稿人。这份报告是该重要机构首次发表的吸烟专题报告,直接促成美国医务总监1964年发表了极具影响力的吸烟与健康专题报告。

我和Fletcher一道研究了慢性阻塞性肺病,研究结果显示一些抽烟者肺部并未受到多大损伤,但有些吸烟者肺功能长年来逐渐丧失,最终引致残疾和死亡。而如果这些遇到麻烦的人在健康严重受损之前戒烟,健康恶化速度就会大幅放缓。

4
另一项研究是什么?

我还协助Richard Doll开展为期20年跟踪英国医生吸烟和死亡专题研究。1951年,Doll调查英国所有医生是否吸烟并跟踪其情况,比较吸烟者、既往吸烟者和从不吸烟者的死亡率。英国医生看到Doll的调查结果后才意识到吸烟真的很严重:它不只是杀死病人,还会致医生于死地!就这样,英国大部分医务人员认可了吸烟危害证据。

在英国医生中,原来烟瘾很大的人成了第一批广大的永久戒烟人群。他们的亲身经历生动显示,停止吸烟可以挽救生命。后来,其他专业人士也开始戒烟,然后戒烟运动扩大到了全国。Doll和我在20世纪70年代发表了20年随访结果,于90年代发表了40年随访结果,并在本世纪初发表了50年随访结果。

5
你为什么专注于研究吸烟,而不是研究可能造成癌症的其它原因?

在上个世纪70年代,有些人认为非吸烟者人群大多数癌症是工作场所和环境污染物所致,他们希望通过动物实验查明哪些工业化学品是致癌物质,并通过禁止这些化学品,大大降低人类癌症死亡率。而Doll和我认为这是不现实的,我们认为癌症主要病因可能不是源自工业界的环境污染物。如果我们的思路正确,那么,过分依赖动物实验可能就会忽略一些真正重要的人类危害,例如吸烟。

有人认为我们将主要注意力放在人类证据上和少数几个致癌因素上是过时的做法。但实际上,在 20世纪70年代,英国男性吸烟者一多半癌症死亡以及越来越多的女性癌症死亡是烟草造成的。


6
如果我们不研究包括环境污染物在内的一切因素,怎么能查明主要原因呢?

过去几十年里发现了很多癌症病因,而有些病因尚待发现。例如,加剧某些类型癌症的风险因素有:某些慢性感染,存储不当食物长出的某些霉菌,含有马兜铃酸的传统药材,一些激素药物,肥胖,以及糖尿病等。

但令人略感欣慰的是,近几十年来,在许多国家中,中年人非吸烟者癌症(或其它疾病)死亡率下降了。所以,我认为不会有像吸烟这么大的非传染性疾病的任何新病因。吸烟导致发达国家癌症总数的四分之一。当然,研究人员最好不要有同样思路,因为那样的话,一旦出错,所有人都错。

我在上世纪70年代以及现在坚持认为,我应该研究许多不同人群过早死亡的主要原因。就挽救的生命数目而言,略微缓解一项主要病因远超一项微小病因的大幅缓解。吸烟致命,戒烟有效,但现在仍有十亿人吸烟。

7
您当年如何做研究?

我们起初只能做中型研究,而现在我们在许多不同国家中围绕慢性病主要原因,不仅针对吸烟,而且还针对主要影响血管疾病而不是主要致癌的因素,例如酗酒、超重和肥胖、糖尿病、高血压和高血脂等,开展大型研究。

一些人原以为,研究这些早就为人所知的风险因素不会发现任何新东西,但实际上我们总会学到新东西。例如,英国的吸烟、俄罗斯联邦的酗酒以及墨西哥的肥胖和糖尿病都是大问题。我们在本世纪发现,戒烟的好处甚至超过早期研究所发现的益处。

8
您在中国从事大规模流行病学研究。您怎么会关注中国烟草流行问题呢?

我是统计学家,知道当今世界99%的人并不是英国人,所以我想进一步了解人口大国中过早死亡的原因。我有幸于20世纪80年代开始与中国科学家共事,此后一直保持着合作关系。

我原以为传染病会是主要死因,但我们的联合调查结果证实,现已不再如此。调查结果还显示,男性吸烟率大幅上升。而此种大幅上升要几十年后才会显现对死亡率的重大影响。

在20世纪80年代,中国的烟草流行问题尚处于初期,很少有人当回事。我建议设立专门制度监测烟草戕害中国居民的程度,并建议监测今后几十年烟草危害变化情况。当时的卫生部长推动了这项工作。


9
您有没有看到你们的研究对中国卷烟销售产生什么影响?

这很难说。我们在上世纪80年代和90年代以及本世纪初在中国各地进行了一系列研究,总共调查了200万人,研究了烟草流行造成的死亡变化情况。1990年,中国成年男性死亡总数的大约10%是吸烟造成的,而到了2010年代,上升到大约20%,到2030年代将达到大约30%。

我们在2015年10月期《柳叶刀》杂志上发表了一篇文章,首次以可靠方式阐述了中国男性和女性吸烟导致的死亡率情况(男性呈上升趋势,女性呈下降趋势)。我不知道我们的工作产生了什么效果,也不知道今后会有什么效果,但至少我们记录了近几十年中国烟草流行状况,并已建立了相关制度,为未来几十年继续记录中国烟草流行状况提供了保障。

10
您的工作与非传染性疾病治疗有何关联?

疫苗接种、环境卫生和治疗服务彻底改变了全球传染性疾病死亡率,另外,治疗服务大幅降低了伤害和非传染性疾病的死亡率,至少在有良好医疗服务的国家中是这样。事实上,我一半的工作是,与牛津大学的同事一道针对血管疾病和乳腺癌开展大规模国际实验和对这两种疾病的各种治疗方法实验结果进行荟萃分析。

11
科学家如何向一般公众有效传达健康风险?

有些科学家努力强调主要风险,而有些科学家则并非如此。如果我们告诉一般公众100个致癌因素,可能会转移人们对导致大量过早死亡因素的注意力,例如对吸烟的注意力。

比如,欧盟每年共有130万名70岁以下的人死亡,其中100多万人死于非传染性疾病,而在这100多万人中,30万人死于烟草引致的疾病。非传染性疾病造成过早死亡的主要原因是吸烟、血压、血脂、糖尿病和慢性感染。不应忽略这几个主要因素。

12
什么因素可能会掩盖这些主要风险呢?

许多较小或不确定的风险。例如,国际癌症研究机构去年宣称,红肉 “可能致癌”。他们没有说红肉肯定致癌,只说有可能致癌,所以,关于它究竟导致多少癌症的合理不确定范围下限是零。

但这份报告获得媒体广泛报道,这也许会加剧人们对有关癌症危害包括烟草致癌危害的新闻报道的普遍疑虑。我不是说我们应该只将注意力放在烟草上,而是说我们不应过多转移对已被可靠证实为主要致癌因素的注意力。

13
流行病学研究人员应该根据其调查结果制定政策来改变人们的行为吗?

不一定。科学成果要想获得人们信任,取得这些科学成果的研究人员也许最好不要过于紧密参与关于如何使用这些结果的政治程序。获取可靠证据和根据这些证据采取行动都有必要,但往往应由不同的人来做。无论从吸烟后果来看,还是从原因来看,都是如此。

例如,如果一包卷烟的实际价格翻一倍,卷烟消费量将减少大约三分之一。世界卫生组织和联合国确定到2030年将吸烟人数减少三分之一,但问题是各国政府每年可从烟草税收和销售中获得大约3000亿美元的收入。如果卷烟实际价格保持不变而吸烟人数减少三分之一,那么,各国政府每年将丧失1000亿美元收入。

但如果增加消费税使卷烟实际价格翻一倍,消费量将减少三分之一,而政府每年将增收1000亿美元收入。这是科学证据,但应由政府和社会决定如何利用这些证据。



The big causes of death from noncommunicable disease

Richard Peto, Professor of Medical Statistics and Epidemiology at Oxford University, was interviewed by Bulletin of the World Health Organization recently, talking about why efforts to reduce premature death from noncommunicable diseases should focus mainly on the big causes.

Richard Peto is a widely influential health statistician, jointly responsible for many large treatment trials, epidemiological studies and meta-analyses. 

Q: You wanted to be an astronomer when you were at school. How did you become interested in medical statistics?
A: By accident. At university I stumbled into statistics without really knowing what it was, then in 1967 I had a job interview with Richard Doll (1912–2005), who had been one of the first to show that smoking caused lung cancer. Towards the end of the interview he asked me why I wanted to work with him as a statistician, and I said: “I don’t know if I do want to – in fact, I don’t even know whether I want a job at all.” I remember his wife saying to me at the first Christmas party: “So you’re the young man who isn’t sure whether he wants to work or not. Have you made up your mind yet?” and I said I hadn’t. At that time I still wasn’t sure that going to work every day was the best thing to do on this planet.

Q: Why did you change your mind?
A: A few months later I started to get my first scientific results. It doesn’t matter how important they actually were, but it is really exciting and interesting to get new results. From then on I worked more and more. In those first few months I would never take work home with me. Now, I never go home without a briefcase, but I was probably a better human being when I was young.

Q: What kind of research were you doing?
A: I was working on many different studies, but two were of particular relevance to tobacco. Charles Fletcher (1911–1995) had written the 1962 report of the Royal College of Physicians on the hazards of smoking, which was the first report on smoking by such a major body, and led directly to the highly influential 1964 report of the US Surgeon General on smoking and health. I worked with Fletcher on chronic obstructive pulmonary disease, showing that some people who smoked cigarettes didn’t get much lung damage, but some suffered progressive loss of lung function over many years, leading eventually to disability and death. If, however, those getting into trouble stopped smoking before their health was severely affected, deterioration slowed substantially.

Q: What was the other study?
A: I was also working with Richard Doll on the 20-year follow-up of his study of smoking and death in British doctors. In 1951 Doll had asked all the doctors in Britain whether they themselves smoked, and was following them up to compare the death rates in smokers, ex-smokers and never-smokers. When British doctors read Doll’s findings they realized smoking was really serious: it wasn’t just killing patients, it was killing doctors too! So, most of the British medical profession accepted the evidence of hazard, and British doctors became the first major group of serious smokers with widespread permanent smoking cessation, providing a nice natural demonstration that stopping smoking saves lives. Later, cessation spread to other professionals, then to the country as a whole. Doll and I published the 20-year results in the 1970s, the 40-year results in the 1990s and the 50-year results in the 2000s.

Q: Why the focus on smoking rather than other possible causes of cancer?
A: In the 1970s some people, believing that most cancers in non-smokers were due to occupational and environmental pollutants, hoped to use laboratory tests on animals to find out which industrial chemicals were carcinogenic, ban those chemicals, and thereby greatly reduce human cancer death rates. Doll and I thought this was unrealistic, and that the big causes of cancer were probably not industry-derived environmental pollutants. If so, a strategy of over-reliance on animal tests risked neglecting the few really important human hazards, like cigarette smoking. Our focus on human evidence and on the few causes of cancer that were known to be big was regarded by some as old-fashioned, even though in the United Kingdom in the 1970s cigarettes were a cause of well over half of all cancer deaths in men and an increasing proportion of all cancer deaths in women.


Q: How can we know what the big causes are unless we study everything, including environmental contaminants?
A: Many causes of cancer have been discovered in the past few decades, and others await discovery. For example, the risk of specific types of cancer is increased by certain chronic infections, by particular types of mould on poorly stored food, by traditional medicinal herbs containing aristolochic acid, by some hormonal medicines, and by obesity and diabetes. It’s somewhat reassuring, however, that in recent decades non-smoker cancer (and other) death rates in middle age have been decreasing in many countries, so I don’t expect any new causes of noncommunicable disease to be as big as smoking, which still causes about a quarter of all cancer deaths in developed countries. Of course, it’s better if researchers don’t all follow the same ideas, as we might then all be wrong. For me, however, what I wanted in the 1970s – and still want now – is for my work to be on the big causes of premature death in many different populations. A moderate reduction in a big cause can prevent far more deaths than a big reduction in a small cause. Smoking kills and stopping works, but a billion people still smoke.

Q: What was it like to do research in those days?
A: At first we could do only medium-sized studies, but now we’ve got big studies in many different countries of major causes of chronic disease, including not only smoking but alcohol, adiposity (overweight and obesity), diabetes, high blood pressure and high blood lipids, which mainly affect vascular disease rather than cancer. Some thought that studies of such old risk factors would not find anything new, but there were always new things to learn – smoking predominated in Britain, alcohol in the Russian Federation, adiposity and diabetes in Mexico, and in the present century the benefits of stopping smoking are even bigger than early studies had suggested.

Q: You conducted big epidemiological studies in China. How did you become interested in the Chinese tobacco epidemic?
A: As a statistician, I knew that 99% of the world is not British, so I wanted to know more about the causes of premature death in populous countries. I was lucky to get the opportunity to work with Chinese scientists in the 1980s, and I’ve done so ever since. I was expecting communicable disease to predominate as a cause of death, but our collaborative surveys confirmed that it no longer did so. The surveys also showed a vast increase in cigarette use by men, an increase that would take several decades to have its main effects on mortality. The Chinese tobacco epidemic was still at an early stage in the 1980s, and few were taking it seriously. I suggested setting up systems to monitor the extent to which cigarettes were killing the Chinese people and to monitor the changes in this over decades, and the health minister at the time facilitated this.

Q: Did you see any effect of your research in China on cigarette sales?
A: That’s difficult to say. We did a succession of nationwide studies in the 1980s, the 1990s and the 2000s involving a total of two million people, documenting how the epidemic of tobacco deaths was evolving. In 1990, smoking was causing about 10% of all adult male deaths in China, in the 2010s it’s causing about 20%, and by the 2030s it will be causing about 30%. Our October 2015 Lancet paper contains the first reliable description of what is happening to male and female mortality from smoking in China (increasing and decreasing, respectively). I don’t know what the effect of our work was or will be, but at least the Chinese epidemic in recent decades has now been documented, and systems are in place to ensure that it will continue to be documented in future decades.


Q: How does your work relate to treatment of noncommunicable diseases?
A: Vaccination, sanitation and treatment have transformed worldwide mortality rates from communicable disease, and treatment has substantially reduced mortality from injuries and noncommunicable disease, at least in countries with good medical services. Indeed, half my work has involved collaboration with colleagues in Oxford on large international trials and meta-analyses of trials of various treatments for vascular disease and breast cancer.

Q: How well do scientists communicate health risks to lay audiences?
A: Some try to emphasize how much the big risks predominate, but some don’t. If we give the general public a list of a hundred possible causes of cancer, it could divert attention from things like smoking that cause vast numbers of premature deaths. In the European Union, for example, there are 1.3 million deaths every year before age 70. More than a million of these are from noncommunicable diseases, including 0.3 million caused by tobacco. The big causes of premature death from noncommunicable disease are smoking, blood pressure, blood lipids, diabetes and chronic infections, and these few big causes should not be obscured.

Q: What might obscure these big risks?
A: Lots of small or uncertain risks. For example, last year the International Agency for Research on Cancer reported that red meat is “probably carcinogenic”. They didn’t say it’s definitely carcinogenic, only probably, so the lower limit of the range of reasonable uncertainty as to how many cancers it causes is zero. Nevertheless, this report generated widespread media coverage, and probably increased general scepticism about news reports about cancer hazards, including those from tobacco. I’m not saying we should concentrate only on tobacco, but we should not divert too much attention away from the big causes of cancer that are proven and well established.

Q: Should epidemiological researchers develop policies based on their findings to change people’s behaviour?
A: Not necessarily. For scientific results to be trusted, it may be best for those producing them not to be too closely connected with the political process of how those results are used. Generating reliable evidence and acting on it are both needed, but should often be done by different individuals. This is true for both the consequences and the causes of smoking. For example, doubling real prices of a packet of cigarettes reduces consumption by about a third. The World Health Organization and the United Nations have targeted a one-third reduction in smoking by 2030, but the world’s governments earn about US$ 300 billion a year in tobacco taxation and sales. If real cigarette prices stay constant and smoking decreases by a third, then the governments of the world would lose US$ 100 billion a year. But if real prices double because of increased excise taxes, this itself will reduce consumption by a third, and the governments would gain US$ 100 billion a year. This is the scientific evidence, but it’s up to governments and society to decide what to do with it.