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Saturday, October 29, 2011

The History Of The Pseudo-Science Of Hormesis

That LNT denier in the last post wasn't particularly charismatic.  He isn't going to scam too many people.

In the last century we had Bernard Cohen who was the consummate hormesis proselytizer.

Here's an old video, lengthy and technical (but scientifically invalid), on the hormesis scam, given to an anti-government regulation group.

You may remember the manufactured “debate” about second hand smoke and cancer back in the 1980’s.  The Surgeon General  & EPA were studying whether or not there was an LNT relationship.  If so, this might mean more government regulation for tobacco companies.  Well, guess who created the “debate” about LNT back then? 

That was the George C. Marshall Institute.
And guess who Cohen is associated with?:
Notice that the video is posted by LibertyInOurTime.   Click on that name, and you can see the anti-government connection.  Notice that commenting is disabled….we can’t have that liberty can we?  The scientific flaws might be posted for the gullible audience.
Also notice that Cohen’s audience is Doctors for Disaster Preparedness.   Behind the name’s genteel facade, they are an anti-government regulation group.  Their last meeting agenda was a mix of anti-global warming & anti-LNT propaganda.    
(They don’t want regulation of fats!  Get ready for the manufactured “debate” on that issue). 
Notice that S. Fred Singer was the first speaker.  He was an early member of the Marshall Institute.
Jump to the Cohen video at about 57:10. Cohen was discussing nuclear physics and says:
 “When I had my first course in this, Professor Seitz who comes to these meetings (meaning DDP meetings)… I was hoping he’d be here….”
That would be Frederick Seitz, Cohen’s old physics professor.  Seitz was responsible for obfuscating the science of cigarette safety in the 1970’s when he worked for R.J. Reynolds. He manufactured  the smoking “debate” back then, and was also an early Marshall Institute member (he died a few years ago).   
This is why Singer was a speaker at the last DDP meeting and why Cohen expected Seitz at the 1997 DDP meeting.

As an aside, this video provides a rich history of global warming science (at the beginning), the Marshall Institute (at about 26:00) and Seitz/Singer (at about 43:00).  I encourage you to watch it as soon as you have time.
For the moment, let’s leave the Cohen video and just pretend you don’t know about Cohen. For some broader historical context. ..that talk was from 6/97.   At that time, radon cancer risk was estimated using BEIR IV (1988) methodology which relied heavily on extrapolation from uranium miner studies.   Miners are exposed to much greater levels of radon than members of the general public.   In the 1990’s, as new homes were built with greater energy efficiency, the potential risk of radon accumulation within them was recognized.  Researchers initiated household prospective case control studies, but these would take years to complete.  Meanwhile, BEIR VI (1999) was published incorporating any new miner or animal studies done since BEIR IV, to improve upon BEIR IV’s risk estimates.

A prospective case control study looks at SPECIFIC INDIVIDUALS (pay attention to that!!) and follows them forward in time, accumulating direct information on the radon concentrations the SPECIFIC individual is exposed to and accounts for other specific risk factors (like smoking) the specific individual experiences.   Significant confounders can be directly observed (and/ or controlled) by the researcher.  One such study was the Iowa Radon Study (2000).

As more and more of these high quality studies were completed, meta-studies were performed which integrated a number of these high quality studies.  One such study was published in the Bulletin of the WHO and another in the British Medical Journal.
In the midst of the 1990’s fervor, Cohen performed a retrospective ecological study (Why would a physicist undertake an epidemiological study?  That's what epidemiologists do! $$$).  This type of study looks back in time.  Confounders cannot be directly observed/controlled by the researcher. 
A well designed (w.d.) prospective case control study has much greater statistical power than a w.d. retrospective ecological study. 
A w.d. retrospective ecological study might identify a county with a high average radon concentration and then identify people who died of lung cancer within it.  But a good researcher doesn't stop there (well, Cohen does)…one estimates the dead people’s ACTUAL radon doses so that radon concentration and absorbed dose are well correlated for each dead person.  Radon concentrations are highly variable.  Two neighbors can have very different average annual radon concentrations in their homes.   That’s why the EPA recommends you test your home, first doing a short term test, then a long term test if warranted by the short term test results.  And, returning to the study, one examines each deceased person’s other specific risk factors (i.e., did that SPECIFIC person smoke?  If so, how many cigarettes did that SPECIFIC person smoke per day?).
Cohen simply uses average county radon concentrations and average county smoking rates. He ignores the need to examine the individuals’ histories.  His study is amateurish.
Does analyzing average county rainfall and average county raincoat ownership tell you much about how wet people get in a particular county?  No.
Now, let’s get into some Cohen video details:  
START-until about 4:30  Cohen engages in a bit of psychological priming by describing the problems that would disappear if LNT is false.  It helps to convince people to convince themselves to support him.  If LNT is false, there would be less government regulations, things would be cheaper.
About 4:30-until about 15:30   Cohen is wrong about:  (a) there is no experimental evidence in support of LNT, (b) “we” don’t consider biological repair mechanisms, (c) spontaneous DNA lesions are indistinguishable from radiation lesions and therefore radiation lesions are trivial, (d) radiation only affects biological repair mechanisms.   I will return to these in a bit.
He goes on to describe the phenomenon of adaptive response, where a large radiation dose (challenge dose) is less deleterious when preceded by a small radiation dose (priming dose).  He omits that as both doses are reduced into the low dose range (the range the “debate” is about!), the adaptive response isn't seen.  He discussed adaptive response in regards to chromosome aberrations, genetic mutations, and the immune system.  Though these responses might play some indirect role in cancer, Cohen omits what would have been the recently released UNSCEAR 1994, which looked specifically at cancer adaptive response and found no clear evidence of it.  Since then, we've found that the latency period (time for a tumor to show up after the doses) can be accelerated or de-accelerated depending on tumor type.  But the overall incidence of cancer has not displayed an adaptive response.
Cohen mentions bone cancer incidence in radium dial painters. He points out that in the low dose range, there is no “experimental” evidence of cancer.  Whoa! A retrospective cohort study is not an experiment.  And of course it doesn't have the statistical power in the low dose range. 
Back to (a) Cohen omits info on the bystander effect, where an irradiated cell has deleterious effects on surrounding cells. Or genetic instability in which the damage doesn't manifest until many cell cycles later.  Or certain cell lines which exhibit hyper-radiation sensitivity.   
I've already responded to (b) in discussing adoptive response.  For brevity I’m done.  
Regarding (c), we now know that not only are the lesions distinguishable and different, but that the repair mechanisms are also distinguishable and different.
Regarding (d), wrong conclusion based on the totality of the evidence.
Cohen’s info in this section is really just more biased psychological priming in support of his “unexpected” study.
About 15:30-until END  The study is described, which I've broadly critiqued.  Cohen claims his study does not incorporate the ecological fallacy because in LNT the average dose represents the average risk.  That latter part is true.  But as discussed earlier, his study still incorporates the ecological fallacy, because he has incorrectly determined average doses and has not resolved confounding factors on an individual basis.
After “correcting” for smoking, Cohen jumps to social-economic variables as possible confounders (based on county averages, not deceased individuals).  He “impresses” us with 54 of these variables and may expand to a couple of hundred.  It won’t matter, because garbage in will yield garbage out, regardless of his quixotic manipulations of the SEV’s.  This is theatre intended to appear as if he’s really trying to resolve the problem.  He ”can’t even imagine” more troublesome confounders like…. oh, I don’t know….. second-hand smoke, asbestos, genetic predisposition, etc. 
P.S.   About 1:02:30 Cohen mentions his offer to eat or inhale plutonium (Pu).  Which is it
It’s eat Pu ….as much as someone else eats in caffeine. 
In that link, he says there is no scientific basis that a single Pu particle inhaled in the lung can cause cancer. 

Then why doesn't his challenge involve inhaling Pu? 

He knows why. 


The guy claiming that LNT is acting like LNT is true!!!

Pu is more toxic when inhaled, rather than ingested.  


I first learned of this video on another blog which seems to consist of LNT-denialists.

This is what the blog owner said, AFTER I posted pretty much all of the above:

"Your “tearing apart" of Cohen was not at all convincing".

That's some heavy denial.

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