Radon's linear dependency

["Field, R. William" <bill-field@UIOWA.EDU>]

Jerry,



That's correct, radon exposure and lung cancer are not linearly 

related.  The BEIR report showed that relative risks based on cumulative 

radon exposure are linear, but with a dependency on age, pack-year rate of 

smoking, smoking duration, etc.



Jerry, let me share my view on this.  I am not trying to persuade others to 

adopt my view, but kindly ask for patience while I present a very 

simplistic example of some of the assumptions I have a hard time 

accepting.  This is not meant to be disrespectful in any way to Dr. 

Cohen.  I am sure we are in agreement with many issues, but using an 

ecologic study to test the LNT does not add up to me.



For example,



Dr. Cohen states he is using his ecologic study to test the validity of the 

LNT.  He has previously agreed that an ecologic test should not be used to 

determine the risk posed by residential radon exposure since that would be 

falling into the trap of the ecologic fallacy.  But, he says he can use his 

ecologic test to examine the validity of the LNT.



I can just not get passed some assumptions that have to be accepted to 

believe this test adds up to a valid test.  In the form of a simplistic 

example, this is in part how I view what Dr. Cohen's test of the LNT does.



For the test of the LNT:



a)  He assumes each person within a county receives the same radon exposure 

(collective dose assumption) - (this assumes that short term basement radon 

concentrations, not seasonably adjusted and not adjusted to reflect home 

occupancy =  radon exposure).



b)  He assumes if the LNT is valid, the counties with higher radon 

concentrations should have higher lung cancer mortality rates.

    ff

c) Just some of his assumptions needed to be correct for this test to be 

valid include: 1) smoking duration and intensity are the same for everyone; 

2) all smokers have the same increased risk of mortality; 3) each person 

within a county spends the same amount of time in the home, etc.



Let's just look at two of his assumptions I struggle with - smoking 

duration and intensity are the same for each person in a county.  They are 

just two of the assumptions you have to buy into if you think this is a 

valid test of the LNT.   But, we all know lung cancer risk is very 

dependent on pack-year rate (smoking intensity), smoking duration, age 

since quit smoking, and many other factors that can not be accounted for in 

an ecologic study.  So, I really do not know what is being tested, but in 

my opinion, I do not think it is the LNT.  In a very simplistic fashion it 

is like testing the validity of the X theory, which states 2 + 3 = 4, and 

when you find out that it does not you say, my study testing the validity 

of the X theory shows 2 + 3 does not equal  = 4.  Then you challenge others 

to explain why 2 + 3 does not equal 4 and you say the X theory must be 

wrong since no one can explain why it does not = 4.



Sorry for the over simplistic example, but I am just trying to share one of 

the struggles I have with using an ecologic study to test the LNT.



Regards, Bill Field 



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