[ RadSafe ] Re: Cameron's refutation of "Alara Does Work"

[John Jacobus]

Jim,
I did not say a large number were disqualified, but
selection was certainly a criteria.  How many would it
take to bias the data?  

--- "Muckerheide, Jim  (CDA)"
<Jim.Muckerheide at state.ma.us> wrote:

> This isn't right.  
> 
> Our discussions with the Navy authorities for worker
> health said that family histories would in fact be a
> basis to preclude a worker from radiation work, but
> that this happened rarely, probably a few dozen
> times (out of 700,000 workers, 108,000 radiation
> workers).  
> 
> They conclude that the few cases would have
> essentially no effect on the statistics.
> 
> Regards Jim Muckerheide
> 
> 
> -----Original Message-----
> From:	radsafe-bounces at radlab.nl on behalf of John
> Jacobus
> Sent:	Thu 6/29/2006 5:41 PM
> To:	howard long; Rainer.Facius at dlr.de;
> jjcohen at prodigy.net; mike.bohan at yale.edu;
> radsafe at radlab.nl
> Cc:	
> Subject:	[ RadSafe ] Re: Cameron's refutation of 
> "Alara Does Work" 
> 
> Dr. Long,
> As one one worked with medical records at one of the
> Naval shipyards, all workers who were involved with
> radiation exposure would have a screen physical. 
> Frequently, those who had relatives with cancers
> would
> be excluded from work involving radiaion.  
> 
> Yes, I would think that this would bias the data,
> leading to a sicker cohort of not non-radaition
> workers.  That is why the study does not exhibit a
> healthy worker effect, despite the conclusion of
> Rainer, who is neither an epidemiologist nor has
> access to the original data.
> 
> Of course, I doubt that this selection bias was
> taken
> into account by Matanoski as she only had the
> records
> but not the directives on worker selection.  
> 
> --- howard long <hflong at pacbell.net> wrote:
> 
> > Ranier, your careful review of the Boice
> commentary
> > on Matanoski's presentation of the vast Nuclear
> > Shipyard Study, confirms my belief that healthy
> > worker effect cannot explain the 3 years of life
> > apparently added by exposure of Gulf Coast workers
> > to 0.5 rem extra.
> >    
> >   The only credible (although minor) healthy
> worker
> > selection I have seen proposed, was here on
> Radsafe.
> > It was that a doctor giving employment exams might
> > unconsciously have directed persons of less
> vigorous
> > health away from imagined hazards of radiation
> > exposure, to otherwise identical work. 
> >    
> >   Howard Long
> >   
> > Rainer.Facius at dlr.de wrote:
> >   Dear John:
> > 
> > Thank you for providing the Boice Jr. (2001) paper
> > commenting on Matanoski's Nuclear Shipyard Study.
> I
> > took some time to compare his remarks with the
> > original report and therefore my reply is somewhat
> > late.
> > 
> > First of all my comparison leads me to conclude,
> > that Boice delivered a very compressed but overall
> > fair summary of Matanoski's report.
> > 
> > Secondly, his assessment of the high general
> quality
> > of Matanoski's work and report is in line with
> > Sponsler and Camerons's (2005) evaluation.
> > 
> > Boice does nowhere claim that the observed
> > significantly lower total mortality of the >= 5
> mSv
> > nuclear as compared to the non-nuclear worker
> group
> > is the result of bias. 
> > 
> > He addresses some points of concern without
> calling
> > into question the principal quality of the
> results.
> > 
> > Boice's concentration on leukaemia data - though
> > understandable - is somewhat moot, given the small
> > number of cases and indeed he does not draw any
> > conclusions from discrepancies with his
> > expectations. 
> > 
> > Regarding race, Boice states "It appears that race
> > was not considered in the analysis which could be
> an
> > important confounder for certain cancers". It is
> > true that Matanoski could not stratify their data
> > with respect to race since the personnel files did
> > not contain this information. It is not true that
> > this confounder was not considered. Mantoniski et
> > al. discuss in quite some length this problem and
> > present their reasons to conclude that their
> > findings would not be seriously affected. 
> > 
> > An objection sometimes raised against the validity
> > of Matanoski's study is the (apparent) absence of
> > the healthy worker effect frequently seen in
> > occupational studies. Boice also does state this
> > absence without drawing the usual conclusion -
> most
> > appropriately so. 
> > 
> > Although the literature does differentiate a dozen
> > or so 'healthy worker effects' the bulk of this
> > selection bias can be attributed to two
> mechanisms,
> > (i) the "healthy worker hire effect" and the
> > "healthy worker survivor effect". The first bias
> > excludes potential workers whose illness prevents
> > them from seeking or finding employment. The
> > corresponding biased SMRs ususally scatter around
> > 0.90 (90%) and hardly ever fall below 0.80.
> > Furthermore this selection bias dilutes within the
> > first years of employment. The "healthy worker
> > survivor effect" results from "differential job
> > migration" either into another less demanding
> > occupation or out of the workforce altogether due
> to
> > illness occurring during employment. 
> > 
> > Although the healthy worker hire effect is
> regularly
> > invoked when radioepidemiological studies find
> > massively lower cancer mortalities (and they
> usually
> > do) to explain this discrepancy with expectations,
> > this argument rarely exceeds the standing of an ad
> > hoc explanation. So far I never have seen this
> > 'explanation to be offered and then accompanied by
> > an obviously mandatory discussion of which checks
> of
> > employment medicals do have prognostic power to
> > select against employers more likely to develop
> > cancer than others. 
> > 
> > Regarding the healthy worker survivor effect I
> have
> > so far not found quantitative data as to its
> typical
> > size regarding non cancer diseases, but here too
> > such arguments - where needed to explain too low
> > radiogenic cancer mortalities - do never accompany
> > its invocation with a proper discussion of what
> > amount of mortality reduction might reasonably be
> > ascribed to it. Apparently, "anything goes".
> > Furthermore, since cancer is predominantly a
> disease
> > of advanced age, the age dependence of the healthy
> > worker survivor effect should be addressed too.
> > Finally, the design of some radioepidemiological
> > studies - such as the studies on European aircrew
> -
> > excluded its influence altogether - which did not
> > prevent some of the investigators to invoke it
> > nevertheless. 
> > 
> > After all, the Matanoski study does exhibit the
> > healthy worker effect for diseases were you would
> > expect to see it, i.e., for mortality from
> diseases
> > of circulatory system - the dominant single cause
> of
> > mortality in the age of workforces. The diagram in
> > the attached PDF-file (again available upon
> request
> > if the moderator intercepts it) clearly
> demonstrates
> > that the healthy worker effect is there as it
> > properly should be. Regarding its absence from
> total
> > cancer mortality, the diagram reveals enhanced
> > mortality from cancers of the respiratory system
> as
> > the cause. Matanoski's report as well as Boice's
> > discussion appropriately invoke known workplace
> > related agents which cause this enhanced cancer
> > mortality which in turn masks the otherwise
> reduced
> 
=== message truncated ===


+++++++++++++++++++
"You get a lot more authority when the workforce doesn't think it's amateur hour on the top floor."
GEN. MICHAEL V. HAYDEN, President Bush's nominee for C.I.A. director.

-- John
John Jacobus, MS
Certified Health Physicist
e-mail:  crispy_bird at yahoo.com

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