Re: Cohen's Observation

[epirad@mchsi.com]

Tom you asked - "Do Field, Lubin, and the EPA agree with Cohen's basic 

observation? If not, which is in error: the radon measurements or the cancer 

incidence information is in error?"

LUNG CANCER DATA

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

We addressed the validity of Cohen's mortality data before.  For the SEER 

states, his mortality data had only mediocre agreement with good incidence 

data.  See our papers in Health Physics.  Cohen used mortality data while 

incidence data is more appropriate. We showed in Iowa (a SEER state) that when 

more valid lung cancer incidence data was used, the inverse association 

disappears. An analyses limited to SEER states 

http://seer.cancer.gov/registries/index.html  would be an vast improvement 

over the mortality data that Dr. Cohen uses. 



Radon Measurements



Look at a county map of the United States. 

http://www.epa.gov/iaq/radon/zonemap.html    Look at the variation in county 

sizes per state.  Imagine how poorly a few short-term (2-7 days tests) radon 

tests represent the radon progeny exposure for individuals in any county, let 

alone huge counties as can be seen on the map.  In fact, many of the 

measurements were made in basements where people spend limited time. 



We showed that if we would have used year long basement measurements in the 

Iowa Study, we would have found a protective effect from radon for lower 

exposures.   http://www.aarst.org/news_pdf/2002_IowaU_Follow-up_Study.pdf

I think most people would agree that short-term screening or long term 

basement measurements do a poor job of predicting radon exposure for an 

individual let alone a county.



In a paper we published in American Journal of Public Health. 80(8): 926-30, 

Aug 1990 showed Dr. Cohen's LSC radon detector had very poor precision.  

However, I would hope that this spot check was not reflective of the overall 

performance of this detector.



A better question then the one you posed may be why is there an inverse 

association between Cohen's county radon concentrations and his county 

estimated smoking rates.  Smoking is correlated with so many other factors 

that also affect lung cancer incidence so adjustment is needed for the total 

combined effects of smoking related factors.  



Remember, we already showed that Cohen's summary smoking information alone 

does a poor job of explaining the lung cancers within the counties. There is 

little surprise that residual confounding exists in his data.  The proof of 

that confounding has been pointed out by Drs. Gilbert and Puskin who clearly 

showed that the inverse association is found for other smoking related cancers.



Regards, Bill Field





Dr. R. William Field

College of Public Health

University of Iowa

http://myprofile.cos.com/Fieldrw



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

> Radsafers,

> Now let me get this straight.

> Cohen's initial observation was that counties in the U.S. with the 

> higher average radon concentrations (real, measured values, albeit 

> averaged across a county population) correlate with lower county lung 

> cancer rates (data provided by NCI); and lower average radon 

> concentrations correlate with higher lung cancer rates.

> I have not heard one argument question the validity of this observation 

> so I have to assume that Field et al. do not contest this observation.

> Is this true? Do Field, Lubin, and the EPA agree with Cohen's basic 

> observation? If not, which is in error: the radon measurements or the 

> cancer incidence information is in error?

> 

> To me this is a very potent observation, and not one to be easily 

> dismissed as Field, Lubin, and BEIR VI have done. To not investigate why 

> this surprising correlation exists would be remiss. How do they explain 

> this observation?

> 

> Tom Mohaupt,

> Wright State University

> tom.mohaupt@wright.edu

> 



> Verily, my own observations from looking into a crystal ball and dimly 

> seeing the other side.

> 



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