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Radon Health Risks





Radsafers, I just signed back on Radsafe for a very short period to post a 

message or two.



Don Smith has been sending me a lot of emails and asking my opinion on 

various topics.  I sent him my previous view (which he sent to Radsafe) 

that briefly presented my view on Dr. Cohen's work.  He has sent me some 

more posts concerning the miner studies.



As for the recent postings concerning miners, I would urge all to consider 

the following observations.  In any examination of the health risks posed 

by radon, there are uncertainties.   Suppose for example there is a lung 

carcinogen that is highly correlated with radon exposure but 

unmeasured.  Then any estimation of radon risk would be enhanced by the 

effects of the unmeasured factor.  This is classical confounding.  With 

clinical trials randomization prevents any unmeasured factors from 

confounding the observed effect, at least in expectation.  Obviously, we 

can not perform clinical trials to determine the long term risk of 

prolonged residential radon exposure.   However, this sort of possibility 

is ALWAYS a limitation with observational studies.  It is used all the time 

by industry to attack occupational studies -- they suggest the potential 

for an unmeasured confounder.  I think that those that suggest that an 

unmeasured confounding factor(s) caused the observed effects must present 

some real data supporting the possibility.  I would urge Duport or others 

to demonstrate that any such (unmeasured) factor: (1) causes a comparable 

level of lung cancer risk (actually it must be a substantially greater risk 

since it won't be perfectly correlated); (2) was present in the mines;  (3) 

is sufficiently correlated with radon exposure to induce the 

effect.  Finally and very importantly, Duport or others must demonstrate 

that this confounding occurred in virtually all miners studies, including 

uranium miners, fluorspar miners, iron miners and tin miners.



If we take a closer look at his suggested factors, silica, nickel dust, 

arsenic dust, diesel soot, and NOx.  Risk of lung cancer from silica is 

very small in general -- a larger risk occurs only in silicotics.  There is 

no strong evidence that silicosis is a huge issue in the various 

mines.  During the years covered in most of the miner studies, I do not 

think diesel engines were used yet underground.  Arsenic did occur in some 

mines, but not in all mines.  In addition, arsenic in dust is more 

associated with dry-drilling, as opposed to wet-drilling, technology than 

with ventilation.  It is also sensitive to the ore body, and not all that 

correlated with radon concentrations.  Is NOx not really a problem , I was 

not aware there was that much combustion.  However, my area of expertise is 

focused more on the residential radon studies than of studies of miners.



The residential radon studies were funded to directly examine the risk 

posed by residential radon exposures (without the need for linear 

extrapolations) and to limit confounding from occupational sources.



Regards, Bill



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

R. William Field, M.S, Ph.D.

College of Public Health

Research Scientist - Department of Epidemiology

Adjunct Professor - Department of Occupational and Environmental Health

Graduate Faculty - College of Public Health

N222 Oakdale Hall

University of Iowa

Iowa City, Iowa  52242



319-335-4413 (phone)

319-335-4748 (fax)

mailto:bill-field@uiowa.edu



College of Public Health   http://www.pmeh.uiowa.edu/index.html

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



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