Re: Cases and Controls

[Tom Mohaupt <tom.mohaupt@WRIGHT.EDU>]

Group,

I too have expressed concerns about the large difference in smoking habits

between the cases and controls. As I recall, the Iowa study states that a

mathematical correction was applied to the data set, but it doesn't address

the methodology? What algorithm was used to "adjust" the data for smoking?

What kind of error bars are associated with the "adjustment". Also, I would

assume the the mathematical association was derived from a subset of the

data and applied to the whole set. How do we know that this application was

unbiased?



Also note that the Iowa study did not discuss the subset of only cases that

were nonsmokers. The author has stated that there were not enough

never-smoking cases to derive statistical significance. This, to me, is a

very important conclusion. Remove smoking and there aren't enough lung

cancers. I'd like to see a study of non-smoking lung cancers that correlate

radon, occupational exposures, passive smoking, pulmonary disease, etc. In

women there are potential confounding factors such as hair spray,

fingernail painting and, in particular, the acetone used to remove the

paint, and perfume. Some women use this stuff everyday. 



I also have a concern about dosimetry. The "track-etch on glass" radon

device seems promising. Note however that it can vary 25% over a single

pane of glass and variability in readings is much greater in houses with

smokers or former smokers. These variabilities become significant when the

RR at 150 Bq/m^3 is estimated to be 1.14. 

Tom



John Williams wrote:

> 

> Dr. Long,

> 

> Your statement that the percent of smoking cases need to match

> the percent of smoking controls in a case control study is

> erroneous.  

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-- 

Thomas Mohaupt, M.S., CHP

University Radiation Safety Officer



104 Health Sciences Bldg

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