Spatial Radon Variation

["Rad health" <healthrad@HOTMAIL.COM>]

Kai wrote:



>Let me quote from the study: "The associations between lung cancer risk and

>observed radon exposures were studied by using LINEAR excess odds 

>models..."

>and the equation used, equation (2), does not show a threshold.



It would not matter if they used a linear model or not, there was an upward 

trend to their risk estimates with increasing radon exposure.  In fact, a 

quadratic may have given them a stronger (more statistically significant) 

association. So in reality it was an upward trend that was not produced by 

using the LNT.



Also, the difference in ratios (in addition to cubic feet living area) 

basement/living area radon between cases and control may have been more 

related to the type of furnace they had.  If they had forced air you would 

see higher radon in the upper levels of the home.  If it was gravity flow, 

water radiator, etc, you would see less radon upstairs.  This information 

may be in their spatial radon paper (Fisher et al.) they reference.



Also, the categories of exposure had no impact on their continuous analyses, 

only their categorical findings.  I think it is good they presented both, 

they could have just presented their categorical findings which showed a 

statistically significant association with BOTH all subjects and live 

subjects. They were more honest then many scientists who may have just shown 

the categorical findings.  However, the general agreement between their 

categorical and continuous analyses support the validity of their findings.  

The continuous and categorical analyses both have their strengths.



Does anyone know how the EPA arrived at the action level of 4 pCi/L?



Don



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