AW: [ RadSafe ] query

Wed Aug 17 18:57:05 CDT 2005

Mike:

Despite my serious disagreement with BEIR VII-2's endorsement of the LNT postulate as a scientific fact, I concur that conspiracy theories like biased committee selection are unreasonable or worse. 

The rows stirred by several anti-nuclear activist organisations and which accompanied the assembly of the committee testify that many members to be were villainised as minions of the nuclear establishment since they were accused of NOT subscribing to LNT. In fact, several of the epidemiologists which are (rightly) renowned for their empirical work on human carcinogenesis from occupational radiation exposure could be quoted as stating that their data on radiation workers are compatible with anything from hormesis to LNT. 

They also often emphasised the relevancy if not the pre-eminence - as far as radiation protection standards are concerned - of findings from studies on truly chronically exposed worker populations above findings from high dose rate studies such as therapeutic or ATB exposures. Yet, from the beginning of their professional career these epidemiologists appear to have been conditioned to somehow regard the ATB survivor findings as the 'gold-standard' of radiation epidemiology. The fact that in the 1970s and 1980s only data from the ATB survivor studies could boast error bars which at least above 200 mSv excluded the y-axis may have biased them to rest content if their own data admitted a LNT line which within the confidence limits did not contradict the ATB LNT line. 

Then, and even more so in the 90s, their data (at least from that handful of really large studies which I happen to know) would have been equally well - and from the parsimony principle even better - represented by a 'no-effect' model, up to say 500 mSv. Still, and without an attempt to justify this self-restraint, the only answer sought from their data was again whether they would be compatible with the then current ATB LNT line. The rationale occasionally given that the ATB data yielded more definite (alias accurate) risk estimates was at least as weak as the DDREF uncertainty was large, not to speak of the other imponderabilities of extrapolating from the ATB survivors to non Japanese worker populations. 

Why despite of their own professional expertise they subscribed to the LNT postulate can only be guessed. One reason may be - in line with still much of contemporary biology - the - with hindsight peculiar - preoccupation with initial DNA damage as the sole determinant of an organism's response to genotoxic substances, among which radiation is just one. In conjunction with their report also the protocols of BEIR VII-2's proceedings back the assumption that this outdated notion might have been influential.

Another, and as I speculate, probably decisive reason might have been the import of the disastrous Brenner et. al. paper published in PNAS 100#24(2003)13761-66. Authored by an excerpt from "Who is Who in radiation biology" it still appears mysterious how that manuscript could make it into the pages of PNAS. Classified by another luminary in radiation research (actually a doyen) as "a horrible paper" and "shoddy work" at least in one detail it is outright fraudulent, i.e., in asserting that in Cardis et al. 1995 a significant increase in leukaemia mortality had been demonstrated. Other aspects such as the design of their figure 2 have again by some most knowledgeable experts been classified as "misleading" where I once more would prefer fraudulent. 

(As an aside: another really strange aspect with this paper - as with all PNAS publications - is that once it has been printed it effectively is immunized against public professional criticism. In contrast to all other scientific journals I know, the NAS offers no manuscript category "Letters to the Editor" or "Correspondence" or "Matters Arising" where controversial aspects of a paper could be publicized. At least at that time I was unable to find a section where I could submit the commentary which I had prepared already.)

So, at least as far the compliance of the 'epidemiology members' of the committee is concerned, my guess is that a mixture of (self-) conditioning, of DNA-'obsession', and the imposing author list of the PNAS paper was instrumental in winning their consent to a conclusion which continues the tradition of leaning on a perceived overriding predominance of the ATB survivor data.

Fortunately, another at least as distinguished scientific body, the French Academy of Sciences nearly simultaneously voiced its opposite appraisal of the biomedical effects of chronic low dose radiation exposures and anybody interested in taking part in the cutting-edge of the respective scientific development is urged to study their report and the references they drew upon (quite a few PNAS papers among them!).

Regards, Rainer

________________________________

Von: radsafe-bounces at radlab.nl im Auftrag von Stabin, Michael
Gesendet: Mi 17.08.2005 17:59
An: Bernard Cohen; RadiatSafety
Betreff: RE: [ RadSafe ] query

For starters, both the Radsafe list and the poll are, as we all know,
not representative samplings of the radiation protection, scientific, or
other communities. I, for one, did not vote because my mind is truly
open on the subject and I don't "favor" any particular model. I think
any honest scientist must say that there is enough evidence for several
competing theories and a lack of understanding of the biological
mechanisms and proposed models that we will not know for some time what
may be happening at low doses and dose rates. I listened to the BEIR
group's defense of their work at the HPS meeting, and it was pretty
reasonable, given what they were working with in the way of data and
what their charge and audience were. I don't agree with every part of
their conclusions, but I found their position to be defensible. I
certainly reject the ideas of conspiracy theories advocated by some on
this list, for the BEIR, ICRP, NCRP, and other groups. I thought that
Feinendegen modeled better than anyone I have seen a way to approach the
data and models in a way that may advance our understanding and lead to
some consensus. People with their heels dug in either for or against one
model or theory do not advance the discussion, particularly when
aspersions are cast at members of other "camps".

Mike

Michael G. Stabin, PhD, CHP
Assistant Professor of Radiology and Radiological Sciences
Department of Radiology and Radiological Sciences
Vanderbilt University
1161 21st Avenue South
Nashville, TN 37232-2675
Phone (615) 343-0068
Fax   (615) 322-3764
Pager (615) 835-5153
e-mail     michael.g.stabin at vanderbilt.edu
internet   www.doseinfo-radar.com

-----Original Message-----
From: radsafe-bounces at radlab.nl [mailto:radsafe-bounces at radlab.nl] On
Behalf Of Bernard Cohen
Sent: Wednesday, August 17, 2005 10:06 AM
To: RadiatSafety
Subject: [ RadSafe ] query

    Considering the opinions expressed on Radsafe and in the recent poll
on validity of LNT, I cannot help but wonder how all the members of the
BEIR VII Committee could unanimously sign off on endorsing LNT. Can
anyone offer an explanation for this? Does anyone know how members of
the Committee were chosen? I cannot help but suspect that their favoring
LNT was an element in their selection.

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