NUCLEAR SHIPYARD WORKER STUDY (1980-1988 & Radiation increased the longevity of British radiologists

["Sandy Perle" <sandyfl@EARTHLINK.NET>]

I am posting the following two articles sent to me by John Cameron, 

and with John's permission, I am posting John's introductory 

comments:

 

>From John Cameron:



An article based on the Final Report on the nuclear shipyard worker 

study (NSWS) to the DOE in 1991 will be submitted to Health Physics 

in a few days. It is an unusual article in that neither of the 

authors (Ruth Sponsler or I) were directly involved in the research. 

I was involved as a member of the Technical Advisory Panel of the 

NSWS. Here is the abstract which you can circulate if you wish with 

the note that the article is being submitted to Health Physics. I 

think there is a good chance that HP will publish it. Best wishes, 

John  



NUCLEAR SHIPYARD WORKER STUDY (1980-1988): A LARGE COHORT EXPOSED TO

LOW DOSE-RATE GAMMA RADIATION. Ruth Sponsler* and John R. Cameron**



* 808-3 College Ave., Clemson SC  29631

** University of Wisconsin-Madison, Depts. of Medical Physics, 

Radiology and Physics PO Box 405, Lone Rock, WI 53556



ABSTRACT: This article is based on the 1991 Final Report of the 

nuclear shipyard worker study (NSWS), the best epidemiological study 

of radiation workers ever done.  The NSWS compared a high dose cohort 

of 27,872 nuclear workers having the highest cumulative doses 

(greater than 5 mGy) to 32,510 controls -unexposed shipyard workers 

with the same ages and jobs.  In addition there was a low dose cohort 

of 10,348 nuclear workers with cumulative doses less than 5 mGy. The 

NSWS was supported by a US DOE contract with the School of Public 

Health of Johns Hopkins University. The contract was to look for 

radiation risks. No risks were found. On the contrary, the high dose 

cohort showed statistically significant health benefits compared to 

the controls.   The dose rates to the high dose cohort from 60Co 

radiation were comparable to dose rates found in high natural 

background areas. The results show that the high dose cohort had a 

death rate from all causes 24% lower (p<10-16) than the controls. In 

addition their death rate from cancer and cardiovascular disease were 

both significantly lower  (p<0.01) than the controls. The DOE 

contract provided for a Technical Advisory Panel of eight outside 

scientists to review the research twice a year. The lower death rate 

from all causes of the cohort compared to the controls contradicts 

the linear no-threshold model of radiation risk and supports a model 

of radiation stimulation of the immune system. The NSWS results are 

similar to the health improvements shown in a recent 100-year study 

of British radiologists. The NSWS and the British radiologist study 

suggest that the ALARA policy may be harmful to the health of 

radiation workers.  We recommend extension of NSWS data from 1981 to 

2001 to get a more complete picture of the health effects of 60Co 

radiation to the high dose cohort compared to the controls.  



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



The following article has been accepted as a Letter to the Editor of 

the British Journal of Radiology the publication date is not set. 

They are waiting for the authors to send a rebuttal. 



Radiation increased the longevity of British radiologists



John R. Cameron

The 100 year study of British radiologists (1) is perhaps the most 

important article about health effects of radiation on humans ever 

published. The continuity of follow-up in the study is the longest 

for any study of exposure to chronic radiation.  The dose range over 

the 100-year study period from 1897-1997 is very large, with 

exposures before 1920 were estimated to be over 100 cSv/y (100 R/y).



The authors appear not to have noticed the health benefits from 

radiation, especially in regard to significantly lower deaths from 

non-cancer even for the earliest radiologists. The very significant 

decrease in deaths from non-cancer and the lack of any significant 

increase in cancer deaths for radiologists after 1920 make it 

apparent that recommended dose limits for radiation workers are set 

too low for good health. The purpose of this letter is to call 

attention to the health benefits of a moderate radiation dose rate 

demonstrated in the data but not mentioned by the authors. 



Table 2 of the article presents the standardized mortality ratio 

(SMR) for deaths from all causes, all cancers and all non-cancers of 

British radiologists compared to the SMR of three groups: (i) all men 

in England and Wales, (ii) all social class I males and (iii) all 

male medical practitioners. Radiologists were divided into four 

groups depending on when they joined one of the two British 

radiological societies: 1897-1920; 1921-1935; 1936-1954 and 1955-

1979. The British X-ray safety committee, formed in 1920, played an 

important role in reducing occupational doses to radiologists in 

later decades 



Early British radiologists (1897-1920) had a SMR for cancer 75% 

higher than the SMR for cancer of all male physicians. The increased 

cancer mortality was clearly a result of their large radiation dose. 

However, even the heavily exposed pre-1921 radiologists a SMR for non-

cancer 14% lower (<0.05) than the SMR for non-cancer of all male 

medical practitioners. Since 80% of the radiologists died from non-

cancer causes, the decreased SMR for non-cancer completely canceled 

their 75% excess cancer mortality.  In other words even the earliest 

radiologists did not suffer any decrease in longevity due to their 

large exposures. The risk could be considered as zero. 



British radiologists' exposures were reduced starting in 1920 due to 

the activities of the British x-ray safety committee.  After 1920, 

radiologists' overall health improved.  Considered as a group, all 

radiologists registered after 1920 (1921-1979) showed no significant 

difference in cancer SMR compared to other physicians. However, these 

radiologists had a significantly lower cancer SMR than all men (SMR = 

0.63, p<0.001) or their class I peers (SMR = 0.82, p<0.01).  In 

addition, the post-1920 registrants had a lower SMR for deaths from 

all causes than other male physicians (SMR =0.91, p<0.01), social 

class I males  (SMR = 0.91, p<0.01), or all men  (SMR =0.72, 

p<0.001).



Cancer rates among radiologists dropped significantly below those for 

the general public starting in 1936 (SMR for 1936-1954 = 0.66, 

p<0.001).  This was at a time when the only dose limit in effect was 

the "tolerance dose" of 0.2 R/day.  



The most dramatic health results are seen in radiologists registered 

after 1955.  Post-1955 radiologists experienced a 32% lower SMR 

(p<0.001) for deaths from all causes than that of all physicians and 

a SMR for non-cancer deaths 36% lower (p<0.001) than that of the 

other physicians. The SMR for cancer mortality was 29% lower (not 

significant) than that for all male physicians. 



This demonstrates a highly significant beneficial effect of radiation 

at moderate doses of radiation.  These doses were probably 

considerably higher than the background dose in most of the world, as 

occupational exposure limits for most of this period were 5 cSv/y, 

although the doses received by the radiologists are not known.   

For the entire 100-year evaluation period, radiologists never had an 

elevated mortality rate from all causes compared to male physicians, 

or the other two comparison groups.   All radiologists registered 

from 1897 to 1997 had a non-cancer SMR 14% lower (p<0.001) than that 

of other physicians, while SMR for all causes was 8% lower ((p<0.01) 

than that of their male medical colleagues.   During no time period 

was the mortality rate of radiologists from all causes higher than 

that of their medical colleagues.



The radiologists' all-cause mortality rates decreased significantly 

below those of all male physicians after 1955.  Why would 

radiologists be healthier than other physicians?  This suggests the 

hypothesis that the improved health of post-1955, of radiologists was 

from stimulation to the immune system.



The table 2 data yields a conclusion that a moderate increase of 

radiation is probably good for the health, yet the authors deny 

overlooked this convincing evidence for beneficial effects of 

radiation. The last sentence of the abstract states: "There was no 

evidence of an effect of radiation on diseases other than cancer even 

in the earliest radiologists …."



When the authors stated that there was no evidence of a radiation 

effect on non-cancer deaths for radiologists, it is apparent that 

they were thinking only of harmful effects of radiation.  However, 

they did not indicate that they were only evaluating harmful effects. 

This leads to the error in the conclusions of the article, and 

suggests that the authors suffered from a perception that radiation 

cannot be beneficial to the health.



The concluding sentence of the article also omits any mention of 

benefits: "For non-cancer causes of death there was no evidence of 

an increased risk in any group, even among those registering before 

1921."  This statement neglects to mention the significantly 

decreased SMR for non-cancer compared to other male medical 

practitioners.



If the early radiologists had no life shortening one has to question 

the logic of the present very low annual recommended dose limit 

for radiation workers (2 cSv/y). This may be so low that it may 

reduce the health benefits seen in radiologists after 1935.  It is 

possible that the first recommended dose limit of 0.2 R/day 

[approximately 50 R/y] for radiation workers set by the International 

Commission for Radiological Protection (ICRP) in 1934 did not need to 

be lowered, because all-cause and cancer mortality rates for 

radiologists registered in 1936 and later were significantly lower 

than those for the general public and were not significantly 

different 

than those for other physicians. Lauriston Taylor, one of the 

founders of the ICRP, wrote in 1980 "No one has been identifiably 

injured by radiation while working within the first numerical 

standards set first by the NCRP and then the ICRP in 1934. …. The 

theories about people being injured have still not led to the 

demonstration of injury and, if considered as facts by some, must 

only be 

looked upon as figments of the imagination."(2)



The British radiologists study will not resolve the controversy 

concerning the validity of the linear non-threshold (LNT) model of 

radiation risk, but it casts doubt on the assumption that low levels 

of radiation have no beneficial effect on humans. 

  

Scientists should be skeptical of a single study that produces 

unexpected results. However, a much larger cohort study of radiation 

workers, the U.S. nuclear shipyard workers study (NSWS) demonstrated 

an equally dramatic beneficial result from exposure to 

occupational radiation.(3) The NSWS compared the health of 28,000 

nuclear workers with the greatest cumulative doses to 32,500 

age matched and job matched unexposed shipyard workers. The nuclear 

workers had a cancer death rate significantly lower 

(p<0.01) than the unexposed workers.  More importantly, the death 

rate from all causes of the nuclear workers was 24% lower (p<10-

16) than that of the unexposed controls. It is unfortunate that this 

important study has not yet been published 14 years after it was 

completed. I was a member of the Technical Advisory Panel of the NSWS 

that consisted of eight outside scientists who met twice 

yearly from 1980 to 1988 to monitor the quality of the study. 

The British radiology data shows that moderate doses of radiation are 

beneficial rather than a risk to the health. Data from the 

shipyard workers supports this conclusion.  The reduced mortality 

among exposed workers, compared to an occupationally similar 

control group, shown in both of these studies contradicts the present 

radiation protection dogma that radiation is a risk down to the 

lowest doses.  Both studies give evidence that humans need a level of 

radiation above natural background in most areas of the world. 

There may be such a thing as radiation deficiency. (4) An optimal 

level may be similar to that received occupationally by post-1955 

radiologists and by nuclear shipyard workers.  Because of the 

mortality deficits seen among the British radiologists and the U.S. 

shipyard workers, it would be ethical to conduct a double blind 

radiation study on humans to resolve the important issue of health 

effects of low dose rate radiation. (4)



References:



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

observation on British radiologists: mortality from cancer and other 

causes 1897-1997. Br J Radiol 74, 507-519 (2001).



2. Taylor, LS. Some non-scientific influences on radiation protection 

standards and practice Health Physics 32, 851-874 (1980)

3. Matanoski, GM. Health effects of low-level radiation in shipyard 

workers final report. 471 pages Baltimore, MD, DOE DE-AC02-79 

EV10095, (1991). 

4. Cameron, JR. Is radiation essential trace energy? Physics and 

Society. October 2001.  Also available at 

http://www.aps.org/units/fps/oct01/a5oct01.html 



***************************************************************

Sandy Perle				Tel:(714) 545-0100 / (800) 548-5100  

Director, Technical			Extension 2306 			

ICN Worldwide Dosimetry Service	Fax:(714) 668-3149 	                

ICN Pharmaceuticals, Inc.		E-Mail: sandyfl@earthlink.net 	

ICN Plaza, 3300 Hyland Avenue  	E-Mail: sperle@icnpharm.com          

Costa Mesa, CA 92626



Personal Website: http://sandy-travels.com

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