Daunt, British Journal of Radiology, 75 (2002),639-640

[Muckerheide <muckerheide@attbi.com>]

Friends,



Courtesy of John Cameron, here is the "other letter" in the BJR (in addition

to John Cameron's letter which he had distributed here when accepted - let

me know, or John, if you also want a copy of his letter).



Notice here the ref to the 2-part papers of Myron and Ludwig in J Nucl Med

2001 (July and Sep).



Also Sont (w/ Ashmore, and Dan Krewski, who, with his analysis of Philippe

Duport's 748 animal study cases, and on BEIR VII, which has just started up

again, may be seeing the light! :-)



Clearly, the message is continuing to build. The drumbeat of history is

crashing on the heads of the Inquisition!



Regards, Jim

Radiation, Science, and Health

http://cnts.wpi.edu/rsh/

==============================



(If you have subscription access to the BJR:

http://bjr.birjournals.org/cgi/content/full/75/895/639 )



Correspondence



Decreased cancer mortality of British radiologists



The Editor‹Sir, 



The article "100 years of observation on British radiologists: mortality

from cancer and other causes 1897­1997" [1] is, I am sure, welcomed by all

those in the field, particularly those who have harboured some lingering

doubt as to the safety of working a lifetime with low dose radiation. In the

abstract the authors state that there was no evidence of an increase in

cancer mortality among radiologists who first registered after 1954 in whom

radiation exposures are likely to have been lower. Indeed, inspection of

Table 2 confirms this. When we look at the entry for all cancers as a cause

of death amongst those who first registered with a professional body between

1955 and 1979 we see that our standardized mortality is a meagre 0.46, which

goes to say that aged-matched men are twice as likely to die of cancer as

radiologists. When this is corrected for socioeconomic class the figure

becomes 0.61, and when it is compared with all male medical practitioners it

is 0.71, a remarkable reduction in the likelihood of dying from cancer

amongst this group of workers in the radiation industry. The authors

attribute this low death rate, at least in part, to the healthy worker

effect. 



The healthy worker effect, although accepted by health physicists and

epidemiologists, is nevertheless a "catch-all" that is used irrespective of

the extent or degree of benefit obtained within the workplace, to avoid

invoking the other scientific conclusion, i.e. there is a benefit to be had,

in this case, from low level radiation.



Although all would agree to a "healthy hire" effect, the extent of "benefit"

seen in this review appears out of proportion. In any event, Baillargeon

[2], in his excellent review of the healthy worker effect published in 2001,

underlines that the healthy worker effect is usually substantially weaker

for mortality from all cancers than for all causes of death, and he

references no less than eight reviews to support that statement. As many of

the readers of this journal will realize (although perhaps relatively few of

the radiologists), there has been a healthy and acrimonious debate

increasing over the last 20 years with respect to the veracity of the linear

no-threshold hypothesis.



This paper is in line with many others in demonstrating a reduced

standardized mortality rate for cancer amongst radiation workers, and it may

be informative for the interested reader to refer to, for example, the

occupational radiation exposure analysis from Canada by Sont et al [3], also

published in 2001, to see another example of this reduction in standardized

mortality. Now that we have plausible radiobiological evidence of (1) the

beneficial effects of low level radiation on DNA function and repair and (2)

the extraordinary low rate of radiation-induced DNA changes in comparison

with those that occur in normal every day life ‹ facts reviewed recently by

Pollycove and Feinendegen [4, 5] ‹ it is perhaps time for scientific honesty

to be established in those that are strongly opposed to any alteration in

the status quo with respect to the linear no-threshold hypothesis.



There is one more point to be made. A standardized mortality ratio of 0.71

for all cancers and 0.68 for all deaths compared with other medical

practitioners (who presumably also registered with professional bodies)

effectively excludes a health worker effect in this group (I'm sure other

doctors don't think of radiologists as being more healthy!).



I personally believe that the abstract and the discussion on this paper

should go further than just saying that there was no evidence of an increase

in cancer mortality among radiologists who first registered after 1954. The

statement should carry on to say that there was a significant decrease in

cancer mortality compared with a normal population as well as compared with

medical practitioners and that, although this may to some extent be related

to the healthy worker effect, a beneficial effect from low level radiation

is not excluded. 



N Daunt 



Queensland X-Ray, PO Box 109, Sunnybank, Queensland 4109, Australia



Received for publication March 19, 2002. Accepted for publication May 9,

2002.



References





1.    Berrington A, Darby SC, Weiss HA, Doll R. 100 years of observation on

British radiologists: mortality from cancer and other causes 1897­1997. Br J

Radiol 2001;74:507­19.[Abstract/Full Text]

2.    Baillargeon J. Characteristics of the healthy worker effect. Occup Med

2001;16:359­66.[Medline]

3.    Sont WN, Zielinski JM, Ashmore JP, Jiang H, Krewski D, Fair ME, et al.

First analysis of cancer incidence and occupational radiation exposure based

on the national dose registry of Canada. Am J Epidemiol

2001;153:309­18.[Abstract/Full Text]

4.    Pollycove M, Feinendegen LE. Biological responses to low doses of

ionising radiation: detriment versus hormesis. Part 1: dose responses of

cells and tissues. J Nucl Med 2001;42(7):17N­27N.[Medline]

5.    Pollycove M, Feinendegen LE. Biological responses to low doses of

ionising radiation: detriment versus hormesis. Part 2: dose responses of

organisms. J Nucl Med 2001;42(9):26N­32N.



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