Re: Spatial Radon Variation

[Kai Kaletsch <info@eic.nu>]

Don,



I have no problems with what you said below. There may be a way that the

study's authors could check on the validity of my original concerns (1.

Change in a house's ventilation as a result of the occupant's lifestyle

change after lung cancer diagnosis. 2. The absence of elevated radon levels

in the basements of cases.)



1. Changes heating fuel consumption (whatever it is: gas, oil,

electricity...) could indicate changes in ventilation. The more you

ventilate in the winter, the more make up air you have to heat. This could

be incorporated into future studies, but you may also be able to get heating

fuel consumption retrospectively. (The relationship is not linear and going

through 0, because some heat is lost through conduction.)



2. You could use the radon concentration distribution described in "Spatial

variation of residential Radon Concentrations: The Iowa Radon Lung Cancer

Study" Health Phys 1998;75:506-13 and calculate the probability of finding

that cases had basements with lower average radon concentration than

controls, given the ERR of 50% per 11 WLM reported in "Residential Radon Gas

Exposure and Lung Cancer: The Iowa Radon Lung Cancer Study" AJE Vol 151

No11.



"Spatial variation of residential Radon Concentrations..." shows a fairly

decent correlation between basement readings and first floor readings and a

large variation of basement readings across Iowa. The other paper reports

that the first floor radon concentration was a large factor in exposure.

That's why I would think that the probability of having the average basement

reading for cases lower than for controls is fairly low. I haven't done any

statistics in ~ 15 years, so maybe someone in that field could help out.

This would be a direct test of LNT.



Kai



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

From: "Rad health" <healthrad@HOTMAIL.COM>

To: <radsafe@list.vanderbilt.edu>

Sent: Saturday, January 26, 2002 11:52 PM

Subject: Spatial Radon Variation





> 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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