Arouet
Member
I basically agree with you, except that you still seem to think that most of the problems in science are statistical.
I'm pretty sure I said that I didn't think that the only problems were statistical.
As I acknowledged above, they are in the case of statins, but if we take that example and explore it a bit further.
If researchers ignore evidence that high cholesterol levels are associated with longer life, it isn't about the statistics as such, it is just very blinkered reasoning.
I agree with that. However, you seem to be jumping to the conclusion that researchers are ignoring this aspect.
The focus, from what I can tell, in most studies has been on cardiovascular risk, and the research seems to consistently show a link between high LDL and higher risk of coronary disease. But what seems to be coming out of the research as well in recent years, is a finding that there is also an association between High LDL and lower risk of all-cause mortality.
This is an issue that should be investigated, and indeed it seems to be something that is being investigated. A study just came out this month looking at that question exactly: Lack of an association or an inverse association between lowdensitylipoprotein cholesterol and mortality in the elderly: a systematic review.
What is makes me wonder is if high LDL increases one risk factor, but also lowers some other risk factors. I imagine they are going to have to break down that all-cause mortality stat to find out which factors vary based on LDL levels.
The link is still, as far as I can tell, well established to the higher risk of heart disease. What this probably points to is that people with other heart disease risk factors are still well advised to seek to lower LDL levels, but that it may be less of a concern for others. Note that the Ibaraki Health Study that you've brought up several times was done on a population that already had low LDL to begin with.
But what you paint as a scandal "why didn't they know this before?????" I see as the steady growth in understanding about these really complicated issues! Your suggestion seems to be that if researchers are doing their jobs well they should be able to figure out all this stuff right off the bat! I don't think its that simple. It takes time to sort all of this out. As the paper I linked above says:
"It is well known that total cholesterol becomes less of a risk factor or not at all for allcause
and cardiovascular (CV) mortality with increasing age, but as little is known as to whether lowdensity
lipoprotein cholesterol (LDLC), one component of total cholesterol, is associated with mortality in the elderly, we decided to investigate this issue."
In terms of advising the public we're in the unenviable position of having to make decisions on this kind of thing with imperfect information. Inevitably this is going to result at times in pushing bad advice. But I'm not sure what the alternative is? Stop public policy health promotion?
Then there is the question of just how effective a drug has to be in order to be prescribed. An effect may be statistically valid, but too small to be of any real use - see my comments above. That isn't a question of statistics, so much as common sense.
Medical studies address this kind of question all the time, from what I've seen. The precise cut off between worth it and not will always be a bit arbitrary, but this is something that is discussed in the literature.
I think the Cochrane 2013 review found that statin use would prevent something like 18 out of 1000 people from dying of heart disease. Whether not that is worth it is a value judgment to be sure. Some people may not consider it worth it, side effects or not, while others will. I guess the question is who should decide? And it may turn out that the research that has been coming out on LDL and all-cause mortality may impact on the advice for statin use as well. That has been brought up in the studies I've looked at too.
I suspect what we're going to see as this research continues is less broad-based advice being given, with specific advice being given to those with certain risk factors.
Many of the problems are quite awful, such as cancer research done on contaminated cell lines. The point about such contamination is that the contaminant cells may grow faster than the intended cells, and overtake the culture completely - so a whole set of research papers are based on totally wrong research.
David
I'm not familiar with the specific case that you're talking about, but I'm sure that its not isolated. Did you think that I would disagree that effort should be made to reduce contamination? Isn't that a methodological issue? It is unfortunate that a single contaminated cell line can impact on a set of research papers coming out of that lab (or labs where they send the cell line), but this highlights the importance on replication. That first line should be the start of the investigation, not the end. Other labs should create their own versions, hopefully uncontaminated, and see if the results replicate. This is exactly the kind of thing I've been talking about!
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