Interesting paper

["Jim Nelson" <nelsonjima@HOTMAIL.COM>]

Dr. Cohen,



Have you seen this paper that says ecological studies can not adequately 

adjust for confounders.  This follows the paper of Legarde that made the 

same conclusion.  They mention your ecologic study as an example. Isn't Dr. 

Doll the first person who made the link between smoking and lung cancer?



Journal of the Royal Statistical Society: Series A (Statistics in Society)



A parallel analysis of individual and ecological data on residential radon 

and lung cancer in south-west England





volume 164: Issue 1





Sarah Darby: Imperial Cancer Research Fund, Oxford, UK

Harz Deo: Imperial Cancer Research Fund, Oxford, UK

Richard Doll: Imperial Cancer Research Fund, Oxford, UK

Elise Whitley: University of Bristol, UK



Abstract:



Parallel individual and ecological analyses of data on residential radon 

have been performed using information on cases of lung cancer and population 

controls from a recent study in south-west England. For the individual 

analysis the overall results indicated that the relative risk of lung cancer 

at 100 Bq m−3 compared with at 0 Bq m−3 was 1.12 after adjusting 

for age, sex, smoking, county of residence and social class. In the 

ecological analysis substantial bias in the estimated effect of radon was 

present for one of the two counties involved unless an additional variable, 

urban-rural status, was included in the model, although this variable was 

not an important confounder in the individual level analysis. Most of the 

methods that have been recommended for overcoming the limitations of 

ecological studies would not in practice have proved useful in identifying 

this variable as an appreciable source of bias.



http://www.blackwellpublishers.co.uk/asp/journal.asp?ref=0964-1998&src=arc&vid=164&iid=1



Jim Nelson







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