Re: Radon in spas versus homes

["H. G Claycamp" <hgc2+@pitt.edu>]

It appears to me that the Russian spa populations fall into the 200-400
WLM range, if they were treated on working day schedules.  If we are to
ascribe to linear no-threshold theories of radiation carcinogenesis,
founded in the Moolgavkar-Knudsen-Venzon or similar models, then dose is
the applicable variable.   Dose-rate x time is expected to show
recirpocity over a significant range of dose.  Of course, reciprocity
breaks down in the extremes (i.e., using H&N cancer responses to predict
low-dose and low-dose-rate regions.  Hence the DDREF.)

While questions of whether or not a Russian study could be performed as a
prospective cohort study or a (retrospective) case-control study are
ultimately needed before the research can be mounted, a more fundamental
question pertains to the dose-rate issue, here using WL as a surrogate
for dose rate: Is 950 WL for 8 to 14 days too
high of an exposure rate for use in comparison with the (e.g.) mining
data? Certainly, the cumulative exposure (perhaps a few hundred WLM) puts
this cohort within the range of exposures experienced in the mining
cohorts (i.e., BEIR IV and IV).  

An optimal approach to resolving this might be to use a mechanistic risk
assessment.  What do the wealth of in vitro and animal studies say
about DDREF for alphas?  If an answer to this question puts us on firm
scientific footing (i.e., DDREF = 1 in this range), then we could address
the particulars of mounting the epi study.

...Just a thought...
	Gregg (hgc2+@pitt.edu)
 - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 
H. Gregg Claycamp, Ph.D., C.H.P. 
Assoc. Prof. and Assoc. Chair 
Dept. of Environmental and 
  Occupational Health 
University of Pittsburgh 
412-967-6524 FAX:  412-624-1020


On Wed, 14 Oct 1998 FIELDRW@aol.com wrote:

> In a message dated 10/14/98 9:59:02 AM Central Daylight Time, MFORD@pantex.com
> writes:
> 
> << Since epidemiological studies in BEIR IV and elsewhere have long
>  lamented the problems of confounding and the lack of reliable
>  measurements in the miner studies, I would question why the
>  medicinal use of radon in other countries (e.g., Russia) have not
>  been considered given the fact that literally millions of people have
>  been treated under a medical setting with optimal concentrations of
>  950 WL over 8 to 14 day periods.  
>  
>  This would seem to be an ideal population to study.  If the EPA and
>  the CDC were truly interested in determining the health effects of
>  radon exposure, it would seem that a study of Russian
>  radon-therapy patients would be the most reliable study group to
>  examine.
>  
>  Any comments? >>
> 
> 
> If one were interested in the effects (high dose - short term) of radon in
> spas, the individuals who frequent spas would serve as a reasonable sampling
> frame.  On the other hand, if one is concerned with residential radon exposure
> as a causative factor in the development of lung cancer, individuals receiving
> a wide range residential radon exposure provides a more representative
> sampling frame.  
> 
> Also, if you are looking at the potential lung cancer risk of "medicinal"
> radon therapy, it would limit the generalizability of the findings.  In other
> words, the findings would be applicable to individuals who are possibly
> already ill (arthritis, poor circulation, etc.).  Many illnesses other than
> lung cancer are related to smoking.  So many more of these spa users versus
> non spa users may go to develop lung cancer secondary to smoking, not radon.
> 
> In addition, the study would be extremely costly because you would have to
> follow the spa users 20-50 years into the future and see which ones developed
> lung cancer.  You would also need a control population (non spa-exposed) that
> was matched by age, sex, etc. to the "spa-exposed" population.  These studies
> are generally referred to as prospective cohort studies.  They are rarely
> performed because of the expense and the number of individuals that would need
> to be enrolled. 
> 
> Regards, Bill Field
> 
> 
> *************************************************8
> R. William Field, Ph.D.
> Department of Preventive Medicine
> University of Iowa
> bill-field@uiowa.edu
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