RE: Radon - county linear model and LNT

["Wesley" <wesvanpelt@ATT.NET>]

Otto and Radsafers,



Dr. Cohen uses the statistical method of stratification to evaluate

confounders (co-variates). This method stratifies the counties into 5 or 10

groups, each with similar values for the co-variate (e.g., dietary level of

a specific nutrient). It is not necessary that co-variates be linear with

lung cancer. All that is necessary is that the co-variate vary monotonically

with lung cancer. That is, as the co-variate increases (or decreases) lung

cancer also increases (or decreases). 



Best regards,

Wes



Wesley R. Van Pelt, PhD, CIH, CHP

Wesley R. Van Pelt Associates, Inc.

http://home.att.net/~wesvanpelt/Radiation.html 

wesvanpelt@att.net 

 



-----Original Message-----

From: owner-radsafe@list.vanderbilt.edu

[mailto:owner-radsafe@list.vanderbilt.edu] On Behalf Of Otto G. Raabe

Sent: Friday, June 27, 2003 11:05 AM

To: BERNARD L COHEN; epirad@mchsi.com

Cc: radsafe@list.vanderbilt.edu

Subject: Re: Radon - county linear model and LNT



June 27, 2003



Dear Bernie:



I think that Lubin is saying that when you plot lung cancer rates versus

radon level you are indirectly assuming a linear relationships between the

overall lung cancer rate and all of the co-variates that may affect the

lung cancer rate. Smoking is an obvious co-variate, but there may be others

such as genetic susceptibility, dietary level of certain nutrients, etc.



Otto







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