[ RadSafe ] Can anyone help with this mystery?

[John Jacobus]

Dr. Cohen,
What do you mean by "as I crudely calculated from the
data they presented?"

--- Bernard Cohen <blc+ at pitt.edu> wrote:

>  A paper by W.N. Sont et al in Am. J. Epidemiol.
> 154:309-318:2001 on 
> radiation monitored Canadian workers in industrial,
> medical, dental, and 
> nuclear power jobs gives the following percentages
> of people dying from 
> cancer vs lifetime accumulated radiation dose (as I
> crudely calculate 
> from the data they present):
> 
>           Dose        % who died      95% confid.   
>          
> 
>           in rem      from cancer      interval     
> 
>             0.25             1.8%             1.8 -
> 1.8       
> 
>              0.75            2.3%             1.9 -
> 2.7      
> 
>              1.5              2.8%             2.4 -
> 3.2        
> 
>              3.5              2.5%             2.1 -
> 2.9        
> 
>               7.5             3.9%             3.2 -
> 4.6        
> 
>               15              3.8%             2.9 -
> 4.7        
> 
>               30              4.8%             3.3 -
> 6.3        
> 
>             >40              6.8%             3.4 -
> 4.2        
> 
>           On the face of it, these data give very
> strong evidence in 
> favor of a linear-no threshold dose response
> relationship extending well 
> below 1.0 rem.
> 
>           However, by the time a person dies, he
> receives a dose 
> averaging about 20 rem from non-occupational
> exposure, and these 
> exposures vary widely, typically between about 10
> rem and 30 rem, in a 
> manner not correlated with occupational exposures.
> Roughly speaking, 
> that means that the numbers for dose in the first
> column above should be 
> increased by about 20 rem and assigned an
> uncertaincy of about 10 rem.
> 
>           Crudely, this converts the above table to:
> 
>          
> 
>           Dose        % who died      95% confid.   
>          
> 
>           in rem      from cancer      interval     
> 
>  
> 
>      10.25-30.25      1.8%             1.8 - 1.8    
> 
>                                                     
>               
> 10.75     -30.75      2.3%             1.9 - 2.7    
>  
> 
>       11.5-31.5         2.8%             2.4 - 3.2  
>      
> 
>       13.5-33.5         2.5%             2.1 - 2.9  
>      
> 
>       17.5-37.5         3.9%             3.2 - 4.6  
>      
> 
>          25-45             3.8%             2.9 -
> 4.7        
> 
>           40-60            4.8%             3.3 -
> 6.3        
> 
>             >50              6.8%             3.4 -
> 4.2            
> 
>  
> 
>           No one could claim that this table gives
> any info on low level 
> radiation in the dose range below 20 rem. But this
> raises another 
> question: why was the first table so deceiving?
> 
>             Can anyone offer an explanation for
> this?
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+++++++++++++++++++
"Never write when you can talk. Never talk when you can nod. And never put anything in an email."  - Eliot Spitzer, New York state attorney general

-- John
John Jacobus, MS
Certified Health Physicist
e-mail:  crispy_bird at yahoo.com

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