(9)乳酪和认知症的假设性研究-Hypothetical Study of Cheese and Dementia-公开课-关爱惟士
(9)乳酪和认知症的假设性研究-Hypothetical Study of Cheese and Dementia

http://player.youku.com/embed/XMjY3ODMzMTYwOA



Dr Maree Farrow

Maree Farrow博士

Often we see headlines in the media that might tell us a certain behaviour will increase our risk of dementia while another behaviour might reduce our risk of dementia. Those headlines, unfortunately, can be misleading. They can leave us believing that we could eliminate our risk of dementia completely simply by eating more chocolate or drinking more coffee. But what do those headlines really mean?

我们经常在媒体上看到告知我们某种行为或许将增加我们患的认知症的风险,而另一种行为可能会降低我们的认知症风险的新闻标题。不幸的是,这些标题或许是误导性的。他们让我们相信可以仅仅通过吃更多的巧克力或喝更多的咖啡来完全消除患认知症的风险。但这些头条真正含义是什么呢?


Let’s talk about how researchers actually find out how a particular behaviour affects our risk of developing dementia. Let’s say we wanted to find out how eating cheese is related to the risk of dementia. Now it’s not, as far as we know. There’s been no studies looking at this, so please don’t worry about eating cheese. This is a hypothetical example that we’re going to use here.

让我们介绍一下研究人员是如何发现某一特定行为是如何影响我们发展认知症的风险的。例如我们想知道吃奶酪是否与得认知症的风险相关。据我们目前所知,不是这样的。 迄今没有任何研究发现这个,所以请不要担心吃奶酪。这是一个我们要在这儿使用的假设性例子。


One of the best ways to look at this question would be to conduct what we call a prospective cohort study. In this type of study, we’d recruit a random sample of people and we’d ask them how much cheese they eat. Then we’d follow them up over a number of years to determine who gets dementia, and whether how much cheese they eat was related to their risk of developing dementia. Then we would use statistics to determine whether eating cheese had a significant effect on your risk of developing dementia and also how big that effect might be.

解决这个问题的最好方法之一是进行我们所谓的前瞻性队列研究。在此类研究中,我们会招募一个随机抽样的人群,我们会问他们吃多少奶酪。然后我们会随访他们多年来确定谁会患认知症,以及他们吃多少奶酪是否与他们的罹患认知症的风险有关。然后我们将使用统计学方法来确定吃奶酪是否对罹患认知症的风险有显著的影响,以及这种影响可能有有多大。


In our hypothetical research study, we’re going to start by recruiting two thousand people who are aged over 65. We’re going to ask them how much cheese they eat and we’re going to split them into two groups. We’re going to take the people who eat more than 100 grams of cheese per week and then the people who eat less than that amount per week. So in this hypothetical study, let’s say we were able to split the group in half. So we have one thousand people who eat more than 100 grams of cheese per week. We’re going to call them the high cheese group. Then we have another one thousand people who eat less than 100 grams of cheese per week, and we’re going to call them the low cheese group.

在我们假设的研究中,我们要询问他们吃多少奶酪,从而分成两组。我们将从招募2000名65岁以上的人开始。我们将每周摄入超过100克奶酪的人放在一组,将每周摄入不到100克奶酪的人放在另一组。所以在这个假设的研究中,我们有每周摄入超过100克的奶酪的一千个人,我们称之为高奶酪组,另外还有由每周吃不到100克奶酪另外一千个人组成的低奶酪组。


To do this study well, we’d need to match our two groups on things like age and gender, the other things that they eat in their diet, and any other factors that might affect dementia risk, so that how much cheese they ate was the only thing that was different about the two groups. We would also test their cognitive function at the beginning of the study, to make sure that they didn’t have dementia at the start. After this baseline testing, we’ll follow our two thousand participants for the next ten years, and we’ll meet with them every two years to test their cognitive function, and in that way we can determine if anyone develops dementia over that time.

为了做好这项研究,我们需要匹配可能会影响认知症风险的这两个组的年龄和性别,他们在饮食中所吃的其他东西,以及任何其他因素,以便使他们吃多少奶酪成为这两个组唯一不同的地方。我们还将在研究开始时测试他们的认知功能,以确保他们在刚开始时没有认知症。在这个基线测试之后,我们将在未来十年里随访这两千个参与者,我们将每两年与他们会面以检测他们的认知功能,从而可以确定在这段时间是否有人发展为认知症。


So in our hypothetical study, let’s say we found that over the ten years 120 people developed dementia. Now 80 of those were from the high cheese group, so that represents 8% of the people in that group who did develop dementia over those ten years.

因此,在我们假设的研究中发现,十多年来有120人发展成为认知症。其中80个人来自高奶酪群,这代表该组8%的人在十年中发展成认知症。


In the low cheese group, however, there were only 40 people who developed dementia, so that represents 4% of the low cheese group.

然而在低乳酪组中,仅有40个人发生痴呆,占该组总人数的4%。


And we might start to think about whether eating cheese is such a good idea. But what do these numbers really mean? There’s two different ways we can look at the findings - depending on whether we’re interested in the effects of eating a lot of cheese or the effects of eating not much cheese.

另外我们可以开始考虑吃奶酪是否是一个好主意。但这些数字真正的含义是什么呢?我们可以有两种不同的方式来看结果 - 取决于我们是否对吃大量的奶酪或吃不太多的奶酪的影响感兴趣。


Let’s first look at how eating high amounts of cheese affects dementia risk in our hypothetical study. From our finding that 8% of people in the high cheese group developed dementia compared to 4% in the low cheese group, we can conclude that eating high amounts of cheese might double the risk of developing dementia. We could also say that eating high amounts of cheese increases the risk of dementia by 100%. Then, as researchers, we would calculate what we call a risk ratio, and in this case the risk ratio is simply eight divided by four, which is two.

让我们先来看看在我们的假设研究中吃大量的奶酪是如何影响痴呆风险的。我们发现,高乳酪组中8%的人发展成认知症,而低乳酪组的发生率为4%,我们可以得出结论,摄入大量乳酪可能会让得认知症的风险增加一倍。我们还可以说,吃大量奶酪会使患认知症的风险增长100%。然后,作为研究人员,我们将计算所谓的风险比,即8除以4,等于2。


A risk ratio of two means exactly the same thing as increasing the risk of dementia by 100% or doubling the risk through eating high amounts of cheese.

风险比率是2,意味着吃大量的奶酪使患认知症的风险增长100%或风险加倍是同一件事。


We would then use statistics to determine if our risk ratio is significant. A statistically significant risk ratio means that we can be reasonably certain there’s a real relationship between eating cheese and the risk of developing dementia, rather than it just being due to chance.

然后我们将使用统计学方法来确定我们的风险比是否显著。统计学上显著的风险比意味着我们可以合理地确认吃乳酪与得认知症的风险之间的确存在着联系,而不仅仅是由于偶然性。


To investigate the effects of eating small amounts of cheese, we would look at our results the other way around. From our results that 4% of people in the low cheese group developed dementia, compared to 8% in the high cheese group, we could conclude that eating small amounts of cheese halves the risk of developing dementia, or that the risk is reduced by 50%. And the risk ratio in this case would be four divided by eight or 0.5. So again having a risk ratio of 0.5 is exactly the same as halving the risk or reducing the risk by 50%. And once again we would need to use statistics to determine if that relationship was statistically significant.

为了调查吃少量奶酪的效果,我们将以另一种方式来观察我们的结果。我们的结果表明,和高乳酪组的8%相对比,低乳酪中的4%的人发展为认知症,我们从而可以得出结论,吃少量乳酪将减半发展成认知症的风险,或将风险降低50 %。在这种情况下的风险比率将是4除以8或即0.5。因此,再次拥有0.5的风险比率与将风险减半或将风险降低50%,含义完全相同。并且我们需要再次使用统计学方法来确定这种关系是否具有统计学意义。


Doubling your risk of dementia sounds pretty scary, while halving your risk of dementia sounds like a good idea. So would you give up eating cheese based on these findings? There are some very important points to remember when looking at research findings like this.

你患认知症的风险加倍听起来很可怕,而减少痴呆的风险似乎是一个好主意。那么你会因为这些发现放弃吃奶酪吗?看到这样的研究结果时,有一些要点需要牢记。


Firstly, although the relative risk of developing dementia was doubled by eating high amounts of cheese in our hypothetical study, the absolute risk changed by only a small amount from 4% to 8%. The other 92% of people in the high cheese group did not develop dementia, despite the fact that they consumed those higher amounts of cheese.

首先,虽然在我们假设的研究中通过摄入大量奶酪使发展为痴呆症的相对风险加倍,但是绝对风险仅从4%变为8%。高乳酪组中其他92%的人没有发展成痴呆,尽管事实上他们消耗了更多的奶酪。


Secondly, a finding like this does not mean that eating cheese causes dementia. What we found was an association between the two things, but this does not represent a causal link.

其次,这样的发现并不意味着吃奶酪会导致痴呆。我们发现的是两个事物之间的联系,但这并不代表一个因果关系。


And finally, a study like this can’t tell us everything about the relationship between eating cheese and developing dementia. What about younger people? If they ate lots of cheese would that affect their risk of developing dementia later in life? What about the type of cheese you eat? Is parmesan cheese better or worse than gorgonzola? And what about the amount of cheese you eat? If 100 grams of cheese per week increases the risk, would 200 grams of cheese per week increase the risk even further?

最后,像这样的一个研究是无法告知我们吃奶酪和发展为认知症之间的关系的一切的。年轻人会怎么样?如果他们吃了很多奶酪会影响他们生命后期发展为认知症的风险吗?你吃的奶酪是哪种类型?是帕尔马干酪比戈尔贡佐拉奶酪更好还是更差呢?你吃奶酪的数量如何?如果每周吃100克奶酪会增加风险,那么每周吃200克奶酪还会进一步增加风险吗?


What this finding means is that older people who eat more of any kind of cheese might have a slightly higher chance of developing dementia. Don’t forget though, this is a hypothetical question. So if I did eat lots of cheese, based on these findings, I might think about cutting back to reduce my risk of dementia, but I would do so knowing that it wouldn’t stop me getting dementia, and I’d also know that it was only one of many choices I could make to potentially reduce my risk of dementia.

这个发现意味着,吃更多的任何种类的奶酪的老年人可能有更大一点的发展为认知症的可能性。但是不要忘记,这是一个假设性的问题。所以基于这些发现,如果我吃了很多奶酪,我可能会考虑削减我患认知症的风险,但我知道这样做不会阻止我得认知症,我也知道它只是我可以做出的潜在降低患认知症的风险的众多选择之一。


Now what would the media make of these findings? We might see headlines such as “Don’t eat cheese if you don’t want dementia”. But we need to look at the research and the real findings behind these headlines to understand how relevant they are to us.

现在媒体会将这些发现做成什么呢?我们可能会看到例如“如果你不想要痴呆,不要吃奶酪”这样的标题。但我们需要看看这些标题后面的研究和真正的发现,从而了解它们与我们的关系。


Here’s an example of some real newspaper headlines from a few years ago. Firstly, “Coffee – just the shot to fend off Alzheimer’s.” And “Caffeine addicts rejoice – a cup a day may keep Alzheimer’s at bay.” You might expect the research was conducted in a similar way to our hypothetical cheese study. A human prospective cohort study investigating the link between coffee consumption and the risk of developing Alzheimer’s Disease.

“咖啡 - 只是防止阿尔茨海默病的镜头”和“咖啡因成瘾者喜出望外 - 一天一杯可能会远离阿尔茨海默病”,这是几年前某些真正报纸头条的一个例子。首先,你可能希望以类似前面我们假设的奶酪研究的方式进行一项人类前瞻性队列研究来调查喝咖啡和发展阿尔茨海默病的风险之间的联系。


However, here’s the title of the article published by the researchers in the Journal of Neuroinflammation in 2008. “Caffeine blocks disruption of the blood brain barrier in a rabbit model of Alzheimer’s Disease”. The participants in this particular study were rabbits fed a high cholesterol diet.

然而,“咖啡因阻断阿尔茨海默病模型兔中血脑屏障的破坏”是研究人员在2008年神经炎症杂志发表的文章的题目。在该研究中的参与者是喂食高胆固醇饮食的兔子。


The researchers tested whether chronic ingestion of caffeine in their rabbits could protect them against changes in the blood brain barrier brought about by their high cholesterol diet. High cholesterol diets and high cholesterol levels, as well as disruptions in the blood brain barrier, have been associated with Alzheimer’s Disease, and also there have been studies suggesting that coffee consumption might be protective against Alzheimer’s Disease. So this is a reasonable research question.

研究人员检测了他们的兔子长期摄入咖啡因是否可以保护兔子们免受他们高胆固醇饮食带来的血脑屏障的改变。高胆固醇饮食和高胆固醇水平以及血脑屏障中的破坏已经被发现与阿尔茨海默病有关,并且还有研究表明咖啡消耗可能会防治阿尔茨海默氏病。所以这是一个合理的研究问题。


The researchers found that in their rabbits, caffeine consumption blocked the usual changes in the blood brain barrier brought about by their cholesterol-rich diet. And the researchers concluded that caffeine, and drugs similar to caffeine, might be effective in the treatment of Alzheimer’s Disease.

研究人员发现,咖啡因的消耗阻止了富含胆固醇的饮食通常带来的兔子的血脑屏障的改变。研究人员从而得出咖啡因和类似于咖啡因的药物可能会有效治疗阿尔茨海默病的结论。


Now it’s rather a long stretch to go from that research to suggesting that humans could fend off Alzheimer’s Disease by drinking more coffee.

目前从这项研究到建议人们可以通过喝更多的咖啡来抵御阿尔茨海默病还有相当长的距离。


The participants in the study were rabbits, not humans. They didn’t have Alzheimer’s Disease. They were fed a cholesterol-rich diet as a potential model for Alzheimer’s Disease. They didn’t drink coffee, they were given pure caffeine in their drinking water. Also, the researchers suggested that caffeine could potentially be used as a treatment for Alzheimer’s Disease, not as something that would prevent Alzheimer’s Disease.

研究中的参与者是兔子,而不是人。它们没有阿尔茨海默病。他们喂养了富含胆固醇的饮食作为阿尔茨海默病的潜在模型。它们没有喝咖啡,在它们的饮用水被添加了纯咖啡因。此外研究人员建议,咖啡因有可能用于治疗阿尔茨海默病,而不是预防阿尔茨海默病。


So be wary about making decisions based on media headlines. They may not accurately reflect the research that they’re based on. And also remember the difference between relative risk and absolute risk. A doubling in the relative risk of developing dementia might be something we should take notice of. But it may mean just a small increase in the absolute risk of developing dementia.

因此,基于媒体头条要谨慎地做出决策。他们可能无法准确反映他们所依据的研究。还要牢记相对风险和绝对风险之间的差异。发展为认知症的相对风险增加一倍或许是我们应该注意的事情。但它可能意味着发展为认知症的绝对风险的一个小小的增长。

翻译:关爱惟士-未经允许不得转载,违者必追究法律责任


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