Testing the validity of the LNT

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

Otto and Bill, 


I think what your asking is that someone explain why a specific

relationship was found using a formula that is not the LNT formula. 

What type of relationship should be found using the Cohen derived

formula, if his formula is not an LNT formula?  The point I made a

couple days ago is that you can only hope to test the LNT if you factor

in smoking duration and intensity in the initial formula since that is

the only way the dose (concentration in this case) - response has a

chance of being linear, if you do not do that you are not testing a LNT

formula.


I have no idea what results Cohen's derived "LNT" formula

should produce.  I think what he is seeing is correct for his

formula.  


A quote from our previous letter, "Cohen (1999a) continues to

challenge scientists to suggest a plausible explanation to explain the

inverse relationship he notes between mean county residential radon

measurements and mean county lung cancer mortality rates. We will call

this inverse relationship "Cohen's Paradox." Cohen (1999a)

states that his challenge is for someone to suggest a "not

implausible model" as a possible explanation and that the burden of

proof will be on him to show that "the explanation is highly

implausible." We maintain that even if additional plausible models

are offered, Cohen will likely not be able to explain his own

paradox. Cohen has not accepted the

fact that it may be impossible to explain Cohen's Paradox in definitive

analytical terms with his existing data because it is not always possible

to identify empirical sources of ecologic bias from aggregate (ecologic)

data alone (Field et al. 1998a)."  Ref:

http://www.lww.com/health_physics/0017-90789-99ltrs.html

Let's first start with a valid formula that factors in smoking duration and intensity.  As I have suggested perhaps this information can be obtained using the methods in Gutrie's paper.  I favor thinking about ways to improve the validity of his formula and available data he has for his analysis rather than trying to explain the fruits of an unsupportable formula.

Regards, Bill Field

Information on the Burlington Health Study:
http://www.public-health.uiowa.edu/baecps/

******************************
R. William Field, Ph.D.
College of Public Health
Research Scientist - Department of Epidemiology
Adjunct Professor - Department of Occupational and Environmental Health
Graduate Faculty - College of Public Health
N222 Oakdale Hall
University of Iowa
Iowa City, Iowa 52242

319-335-4413 (phone)
319-335-4748 (fax)
mailto:bill-field@uiowa.edu
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