[ RadSafe ] Re: Radon and Lung Cancer

Wed Feb 14 10:23:38 CST 2007

My paper responding to this is attached. To summarize briefly, The 
regression of lung cancer vs radon has a negative slope, B = -7.3, 
whereas LNT predicts B = +7.3, a discrepancy of about 25 standard 
deviations. Wes Van Pelt found that there is a very strong correlation 
between radon and elevation (above sea level), and between lung cancer 
and elevation. If this is taken to be a confounding factor in the radon 
vs lung cancer relationship, it reduces the negative value of B by half, 
to B = -3.6. This is still a long way from the LNT prediction, but Wes 
feels that it is close enough to B = 0 (it is still about 6 standard 
deviations away) -- he calls this a "flat line relationship" -- to 
negate any support for a hormesis interpretation.
    On the other hand, if the correlation between elevation and lung 
cancer is interpreted as an explanation for the correlation between 
elevation and radon,  there is no effect on the radon vs lung cancer 
relationship and B = -7.3 is not affected. Thus, saying that the 
elevation vs lung cancer relationship cuts the negative value of B in 
half is an upper limit on its effect.
    The issue here is what really affects the lung cancer rate, radon or 
elevation? Wes thinks it is elevation, due to differences in oxygen 
concentrations in air. It should be noted that this is not a matter of 
the difference between mountain tops and sea level. The median elevation 
of all counties is 803 ft, and half of them are between 497 and 1313 ft, 
which is not a great difference in oxygen concentrations. I interpret 
the correlations as due to the fact that high radon levels tend to be 
far from sea shores (Colorado and Iowa are the highest states)  and the 
entire center of the country is at the above elevations. But everyone is 
entitled to judge between our two viewpoints. I don't consider this to 
be vitally important because my goal was to test LNT and the conclusion 
from that test is unequivocal.

Wesley wrote:

>Dear Otto, Bernie and Radsafe,
>
>I would like to remind you of my paper in Health Physics (October 2003):
>
>EPIDEMIOLOGICAL ASSOCIATIONS AMONG LUNG CANCER, RADON EXPOSURE AND ELEVATION
>ABOVE SEA LEVEL - A REASSESSMENT OF COHEN'S COUNTY LEVEL RADON STUDY
>
>In this paper I plot the county average lung cancer rate vs. the elevation
>above sea level (altitude) and show an inverse association between county
>average lung cancer rate and elevation. I postulate that the decrease in
>lung cancer rates with higher elevations is caused by the carcinogenic
>effect of higher absolute oxygen concentration in the inspired air at lower
>elevations. Stratifying Cohen's lung cancer vs. radon data into ten groups
>of counties with similar elevations removes some, but not all, of his
>inverse association between radon and lung cancer.
>
>This correction for the confounding effects of altitude produces more of a
>"flat line" relationship between radon and lung cancer.... i.e., no
>association between ambient indoor radon levels and lung cancer. 
>
>Those who are convinced that ambient indoor radon causes lung cancer have
>not, in my opinion, satisfactorily explained away Prof. Cohen's study.
>
>Best regards,
>Wes
>Wesley R. Van Pelt, PhD, CIH, CHP
>Wesley R. Van Pelt Associates, Inc.
> 
>-----Original Message-----
>From: radsafe-bounces at radlab.nl [mailto:radsafe-bounces at radlab.nl] On Behalf
>Of Otto Raabe
>Sent: Monday, February 12, 2007 12:02 PM
>To: Bernard L. Cohen
>Cc: 'RADSAFE'
>Subject: Re: [ RadSafe ] Re: Differences in Background radiation and disease
>incidence
>
>At 08:28 AM 2/12/2007, Bernard L. Cohen wrote:
>  
>
>>         ---The problem is that the "powers that be" refuse to consider 
>>such evidence. My radon study does what you say with tremendous 
>>statistical accuracy, and it treats over 500 potential confounding 
>>factors, and does a lot of other things with no statistical uncertainty, 
>>but it is ignored. They refuse to even consider an ecological study and 
>>they ignore all the evidence I have presented.
>>    
>>
>>>**********************************
>>>      
>>>
>
>February 12, 2007
>
>I believe that Prof. Cohen's studies provide the most reliable available 
>information about radon risk to the general public because they are based 
>on appropriate dosimetry. In his studies he used overall average 
>radon-in-home measurements in each U.S. County as a surrogate for relative 
>lifetime average alpha radiation dose rate to the respiratory tract for 
>people living in each County. It is the LIFETIME average alpha radiation 
>dose rate to the lung that needs to be considered in estimating the risk 
>from radon in homes.
>
>In contrast, the case-control studies of indoor radon such as are presented 
>in BEIR VI (e.g. Figure G-1, page 377) use selected isolated measurements 
>of radon concentration in each individual's home for each case or control 
>and there is no way that these measurements can properly represent the 
>LIFETIME average alpha radiation dose rate to the lung of any individual in 
>contrast to other selected individuals. In addition, the resulting widely 
>variable results are used to assign a risk relative to ZERO lifetime alpha 
>radiation dose to the lung even though there is not one single person in 
>the study whose lifetime dose is zero. Then, with these totally imprecise 
>surrogate estimates of lung dose for specific individuals, a regression 
>analysis is performed fitting these imprecise data to a log-linear (in the 
>case of Figure G-1) or linear function beginning at zero dose. I think the 
>results of these types of studies are inherently unreliable.
>
>Otto
>
>
>**********************************************
>Prof. Otto G. Raabe, Ph.D., CHP
>Center for Health & the Environment
>University of California
>One Shields Avenue
>Davis, CA 95616
>E-Mail: ograabe at ucdavis.edu
>Phone: (530) 752-7754   FAX: (530) 758-6140
>***********************************************  
>
>  
>

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