Re: Dumb questions and comments on ecological/case studies

[epirad@mchsi.com]

Cohen stated, 

--According to LNT, something like 10% of lung cancers 

are due to

> > radon; moreover, variations in radon levels among 

U.S. counties are very

> > much larger than variations in smoking prevalence; 

moreover, radon levels

> > are determined by geology and house construction, 

and neither of these is

> > obviously related to smoking, so correlations 

between radon and

> > smoking cannot be very large. In fact, correlations 

between radon and any socioeconomic variables are not 

large.



----------------------------

I can't resist gnawing (yet again) on the above 

statement by Dr. Cohen.  If you are bored with this 

thread, please set your filter to delete my messages. 



When we regressed Cohen’s adjusted smoking percentages 

for males and females on Cohen's radon levels.  In both 

instances there was a significant (p < 0.00001) negative 

association between smoking and radon.  The slopes were 

2.698 for males and 1.981 for females.  Apparently, 

there are more smokers in counties with low radon 

levels.  Since smoking is by far the leading cause of 

lung cancer, mortality rates will be elevated in 

counties with lower radon levels.  In order to get a 

clear picture of the association between radon and lung 

cancer, it is essential that smoking be adequately 

controlled.  However, this will not be possible due to 

the crude classification of exposure (smoker/nonsmoker) 

used by Cohen.



The correlation between radon and lung cancer does not 

have to be large to cause the effect seen by Cohen (in 

part because of the large risk posed by smoking)since 

many other adverse health factors are correlated with 

smoking including socioeconomics, healthcare, etc.  All 

of these factors add to more lung mortality in lower 

radon counties.  



Cohen's poor accounting for the cumulative effect of 

these factors causes his inverse findings.  This 

assertion is supported by the fact that his inverse 

correlation is found for other smoking related cancers 

that should not be associated with radon.  



Bill Field



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

You are currently subscribed to the Radsafe mailing list. To unsubscribe,

send an e-mail to Majordomo@list.vanderbilt.edu  Put the text "unsubscribe

radsafe" (no quote marks) in the body of the e-mail, with no subject line.

You can view the Radsafe archives at http://www.vanderbilt.edu/radsafe/