Re: Mossman paper in Health Physics News - The Debate is Over

[epirad@mchsi.com]

Dr. Cohen,



I know you will disagree with this statement, but in my opinion, you have not 

responded to many of my points in either a direct or convincing fashion.  In 

fact, in many cases, you have ignored my points focusing rather on what you 

thought you could respond to.    



I will pick one instance where we in a publication in the HPJ suggested a 

plausible reason for your inverse findings.  In Field, R.W., Smith, B.J. and 

Lynch, C.F. Ecologic Bias Revisited, A Rejoinder to Cohen’s Response to 

Residential radon-222 exposure and lung cancer: testing the linear no-threshold 

theory with ecologic data. Health Physics. 75(1): 31-33, 1998. We 

stated, “Cohen’s inability to eliminate the residual confounding of smoking 

provides a plausible reason for his observed negative correlation between mean 

county radon concentrations and lung cancer mortality.” 



In the previous email I pointed out that - your smoking data is co-correlated 

with socioeconomic status, poor health care, apartment living, mobility, lower 

education status, etc.  You have never assessed all these variables in a 

multivariate analyses.  And in fact, this would be impossible to adequately 

because of the non linear relationships between these factors within and 

between counties.  



Your often repeated response is “Even a perfect negative S-r correlation does 

not give a positive b value”.  



My response has been over the years is that you can not just look at your 

estimated county smoking information, you must also look at the co-variates of 

county smoking.  Additional use of poor summary county smoking data alone can 

not be used to validate your findings. 



I respectfully understand that you will not agree that residual confounding 

from smoking, and co-correlated variables, is a plausible explanation so 

according to your latest offer stating that you “would be happy to accept the 

judgment of a prominent scientist (with no prior opinions about my study) 

mutually agreed to by the submitter and myself, and willing to publish a paper 

on this with the submitter and myself as coauthors, with each of us explaining 

our viewpoints",    please suggest a few scientists whose decision you would 

accept.  



I am sure we would also both welcome suggestions on scientists from Radsafe.  

Honestly though, I am not sure how one can really validate that the scientist 

has no a priori opinion on this matter.  



Please understand I do not want any award, but rather a conclussion to this 

debate.  



I do agree with Mossman that it is up to Dr. Cohen to offer real evidence that 

radon has a protective effect under about 300 Bq/m3. The residential case-

control studies do not support the presumption that radon has a protective 

effect.  And as we know, findings from ecologic studies are "validated" using 

analytic studies such as case-control studies (not the other way around).



Bill Field

epirad@mchsi.com

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