[ RadSafe ] Do Healthy Workers Negate Cameron's refutation of "Alara Does Work"?

howard long hflong at pacbell.net
Fri Jun 30 12:40:03 CDT 2006

Fellow Students of Radiation Hormesis,
  Is the low CV death rate (as well as cancer death rate) in NSW exposed to >0.5 rad   evidence that selection of healthy workers, not radiation hormesis, explains the 3 years better longevity? I believe not. I would appreciate Pollycove, Sponsler and others from Rad-sci commenting.
  Circulatory disease also seems prevented by radiation - better at high mountain state levels rather than low Gulf Coast levels. Mechanism for this may be inflammation, as measured by high C reactive protein, associated with heart disease at about the level 
of high cholesterol, and a proxy measure of heart disease and death I encourage for  study because of weeks rather than years to measure effect.
  Howard Long
Rainer.Facius at dlr.de wrote:
  Dear John:

If in fact this hiring policy was strictly adhered to - in the epoch where Matanoski's study population was hired (I realized that other contributions here deny this) - suspected cancer prone workers would indeed have been diverted from the nuclear to the non-nuclear workers and that would be consistent with the observation that their mortality from cancers (and only from cancers) was above the reference population level. 

If your assertion pertains, I agree therefore that the Matanoski data would be mute regarding a beneficial - as well as a detrimental - association of radiation with cancer mortality. 

Regarding non-cancer mortality and in particular mortality due to diseases of the circulatory system, Matanoski's original data (table 3.6) DO SHOW - as one reasonably could expect - the proper healthy worker effect with the added feature of a consistent and significant beneficial trend with increasing radiation dose (see my histogram). 

The beneficial association with non-cancer mortality is indisputable. It is strong enough to persist even in the total mortality data notwithstanding the obvious and recognized presence of workplace agents leading to enhanced mortality from cancers of the respiratory system - which affected all worker groups to the same degree. How you interpret this association is a different question. 

Kind regards, Rainer

BTW: My hands-on statistical expertise to analyse such data meets the requirements for any common epidemiologist. Regarding the technical expertise necessary to generate such data with the quality necessary for a meaningful analysis I rely on Boice's (and others) judgment that Matanoski at al. did an excellent job 

Dr. Rainer Facius
German Aerospace Center
Institute of Aerospace Medicine
Linder Hoehe
51147 Koeln
Voice: +49 2203 601 3147 or 3150
FAX: +49 2203 61970

-----Ursprüngliche Nachricht-----
Von: John Jacobus [mailto:crispy_bird at yahoo.com] 
Gesendet: Donnerstag, 29. Juni 2006 23:50
An: Facius, Rainer; hflong at pacbell.net; jjcohen at prodigy.net; mike.bohan at yale.edu; radsafe at radlab.nl
Betreff: Re: AW: Cameron's refutation of "Alara Does Work" 

In our government programs, it was directed that individuals with a history of or a family history of cancer would be evaluated for work involving radiation exposure. This is one reason the incidence of cancers for shipyard workers refueling and repairing nuclear ships were less than that for the general population.

You had to be associated with this work to know that. 

--- Rainer.Facius at dlr.de wrote:

> "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:
> I have no means to assess the bearing of this suggestion in the 
> nuclear shipyard context.
> In my (German) experience an employer offering a specific open 
> position sends applicants which first of all he sees fit for a 
> specific task to a physician together with an elementary workplace/job 
> description. The result of the physician's employment medical is 
> conveyed to the employer in terms of:
> "Yes or No" the applicant is fit for the specified job - period.
> In this setting it is beyond the discretion of the physician to direct 
> someone to another position and hence here this selection bias could 
> be ruled out.
> Best Regards, Rainer
> Dr. Rainer Facius
> German Aerospace Center
> Institute of Aerospace Medicine
> Linder Hoehe
> 51147 Koeln
> Voice: +49 2203 601 3147 or 3150
> FAX: +49 2203 61970
> ________________________________
> Von: howard long [mailto:hflong at pacbell.net]
> Gesendet: Mittwoch, 28. Juni 2006 20:05
> An: Facius, Rainer; crispy_bird at yahoo.com; jjcohen at prodigy.net; 
> mike.bohan at yale.edu; radsafe at radlab.nl
> Betreff: Cameron's refutation of "Alara Does Work" 
> 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.
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