Re: residency in home

[RuthWeiner@AOL.COM]

In a message dated 1/8/02 12:03:19 PM Mountain Standard Time, JohnWi@law.com writes:



> I agree that residency in the home is very important.  
>
>
> That is one reason I like the Iowa Study.  The median time the 
>
> subjects spent in their current home was over 30 years and at least 
>
> 20 years. They also weighted their exposure estimates by the time 
>
> spent in the home.

For this kind of study, "median" is relatively meaningless.  The minimum number of 20 years is the meaningful number.



> The Iowa Radon Lung Cancer Study was a large-scale epidemiology 
>
> study, funded by the National Institute of Environmental Health 
>
> Sciences that assessed the risk posed by residential radon exposure. 
>
> The study was performed in Iowa and the participants were women 
>
> throughout Iowa who lived in their current home for at least 20 
>
> years. 


Shouldn't they also have had a control group of women that has lived in a low-radon area for at least 20 years?


> 3. Why was the study performed in Iowa? 
>
>
> The study was performed in Iowa for several reasons. Iowa has the 
>
> highest average radon concentrations in the United States. In 
>
> addition, women in Iowa tend to move less than most other states, 
>
> which makes calculation of their past radon exposure easier. Iowa was 
>
> also selected because it has a quality cancer registry, which helped 
>
> us identify women who developed lung cancer. 


Again "tend to move less" is meaningless -- I guess here it means they could find women who had been in their homes for 20 years or more.  Also, it's the actual radon concentration in the home that matters -- not the radon concentration throughout Iowa.


> 5. Why were only women selected for the study? 
>
>
> The study was limited to women, because they historically tend to 
>
> spend more time at home and they have less occupational exposure to 
>
> other lung carcinogens. 

After getting over my shock at the sexism of this last, I must again ask: but  the women in the study?  Did all of them spend "more time at home" (more than men, presumably) for at least 20 years?   "Historically" means only that this provided a criterion for selecting Iowa. 


The most questionable aspect is the absence of a control group.  In addition, there would have had to be correction for smoking.


Ruth Weiner, Ph. D.

ruthweiner@aol.com