[R] Relative Risk in logistic regression

[David Winsemius]

On Feb 3, 2013, at 8:15 AM, aminreza Aamini wrote:

> Dear Coleagues ,
> As my friend John  mentined,* the measure of association from a  
> logistic
> regression is the odds ratio, not the relative risk*. but the point  
> is in
> follow-up studies, it is commonly preferred to estimate a risk ratio  
> rather
> than an odds ratio. Thats why im looking for RR in logistic models.
> Bytheway thank you all for ur consideration.
> Amin

I agree that the relative risk is generally preferred in presenting  
the results of follow-up studies. The question should be:  why do you  
want to use a logistic link? The technical report out of the  
University of Washington Biostatistics Depeartment explains a variety  
of approaches including using a log-binomial model and Poisson  
regression. Either of those can be done in R with glm. The Poisson  
regression model is particularly simple to develop.  You should  
explain a)  what sort of data you have in greater detail and b) your  
reasons for using the logistic link when arguably better alternatives  
are available if you want a more specific answer.

-- 
David
>
>
> On Sun, Feb 3, 2013 at 1:42 PM, Michael Dewey  
> <info at aghmed.fsnet.co.uk>wrote:
>
>> At 10:49 30/01/2013, aminreza Aamini wrote:
>>
>>> Hi all,
>>> I am very grateful to all those who write to me
>>> 1) how i  can  obtain relative risk (risk ratio) in logistic  
>>> regression
>>> in R.
>>>
>>
>> @TECHREPORT{lumley06,
>>  author = {Lumley, T and Kronmal, R and Ma, S},
>>  year = 2006,
>>  title = {Relative risk regression in medical research: models,  
>> contrasts,
>>          estimators, and algorithms},
>>  number = 293,
>>  institution = {{UW} Biostatistics Working Paper Series},
>>  keywords = {glm, Poisson},
>>  url = {http://www.bepress.com/**uwbiostat/paper293<http://www.bepress.com/uwbiostat/paper293 
>> >
>> }
>>
>> }
>>
>>
>> 2) how to obtain  the predicted risk for a certain individual using
>>> fitted regression model in R.
>>>
>>> Many thanks, in advance, for your help.
>>>
>>> Amin.
>>>
>>
>> Michael Dewey
>> info at aghmed.fsnet.co.uk
>> http://www.aghmed.fsnet.co.uk/**home.html<http://www.aghmed.fsnet.co.uk/home.html 
>> >
>>
>>
>
> 	[[alternative HTML version deleted]]
>
> ______________________________________________
> R-help at r-project.org mailing list
> https://stat.ethz.ch/mailman/listinfo/r-help
> PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
> and provide commented, minimal, self-contained, reproducible code.

David Winsemius, MD
Alameda, CA, USA