[R] How to do adjust for sex, age, genotype for a data

2009-07-17 Thread 1Rnwb

Hello R gurus,

I am biologist doing biomarker research and I have a data set where I have 6
proteins and close to 3000 samples, i have to look for differences between
disease(Y) and controls(N) along with genetic risk, genotypes, sex and other
demographic info available. however i do not know any of the statistics to
do the adjustment for sex, age, genotype, genetic risk. I have been reading
in papers where the authors are talking about adjusting for age, sex,
genotype, genetic risk. The CDC website suggests for adjusting the age using
the weights, but I am not sure as this would apply to my data. one website
says that if the distribution is not equal then one has to model sex, age
and other demographic parameters as co-variates. I would appreciate if
someone can help me to understand this more clearly and provide directions
on modeling these to do my analysis. I am attaching a sample data file with
this post. Thanks
http://www.nabble.com/file/p24534963/Sample%2Bdata.csv Sample+data.csv 
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Re: [R] How to do adjust for sex, age, genotype for a data

2009-07-17 Thread Frank E Harrell Jr

1Rnwb wrote:

Hello R gurus,

I am biologist doing biomarker research and I have a data set where I have 6
proteins and close to 3000 samples, i have to look for differences between
disease(Y) and controls(N) along with genetic risk, genotypes, sex and other
demographic info available. however i do not know any of the statistics to
do the adjustment for sex, age, genotype, genetic risk. I have been reading
in papers where the authors are talking about adjusting for age, sex,
genotype, genetic risk. The CDC website suggests for adjusting the age using
the weights, but I am not sure as this would apply to my data. one website
says that if the distribution is not equal then one has to model sex, age
and other demographic parameters as co-variates. I would appreciate if
someone can help me to understand this more clearly and provide directions
on modeling these to do my analysis. I am attaching a sample data file with
this post. Thanks
http://www.nabble.com/file/p24534963/Sample%2Bdata.csv Sample+data.csv 


If the only clinical variables you are adjusting for are age and sex 
this analysis will be misleading at best.


Frank

--
Frank E Harrell Jr   Professor and Chair   School of Medicine
 Department of Biostatistics   Vanderbilt University

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Re: [R] How to do adjust for sex, age, genotype for a data

2009-07-17 Thread 1Rnwb

then what will be the other factors needed to be adjusted and whether I
should adjust or use them as covariates. Finally how these analysis will be
done in R


Harrell, Frank E wrote:
 
 1Rnwb wrote:
 Hello R gurus,
 
 I am biologist doing biomarker research and I have a data set where I
 have 6
 proteins and close to 3000 samples, i have to look for differences
 between
 disease(Y) and controls(N) along with genetic risk, genotypes, sex and
 other
 demographic info available. however i do not know any of the statistics
 to
 do the adjustment for sex, age, genotype, genetic risk. I have been
 reading
 in papers where the authors are talking about adjusting for age, sex,
 genotype, genetic risk. The CDC website suggests for adjusting the age
 using
 the weights, but I am not sure as this would apply to my data. one
 website
 says that if the distribution is not equal then one has to model sex, age
 and other demographic parameters as co-variates. I would appreciate if
 someone can help me to understand this more clearly and provide
 directions
 on modeling these to do my analysis. I am attaching a sample data file
 with
 this post. Thanks
 http://www.nabble.com/file/p24534963/Sample%2Bdata.csv Sample+data.csv 
 
 If the only clinical variables you are adjusting for are age and sex 
 this analysis will be misleading at best.
 
 Frank
 
 -- 
 Frank E Harrell Jr   Professor and Chair   School of Medicine
   Department of Biostatistics   Vanderbilt University
 
 __
 R-help@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.
 
 

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Re: [R] How to do adjust for sex, age, genotype for a data

2009-07-17 Thread Charles C. Berry

On Fri, 17 Jul 2009, 1Rnwb wrote:



then what will be the other factors needed to be adjusted


It is NOT an exaggeration to say that hundreds of research 
papers, dozens of books, and many dissertations have been written on how 
to go about answering that question in one context or another.


Given the background you say you have, I doubt that any advice you will 
get from this list will enable you to craft a good answer.


What you really need is collaboration with or mentoring from someone 
who is expert in these matters and willing to dig into the particulars of 
your research area.



and whether I

should adjust or use them as covariates.


Usually, these amount to the same thing.


Finally how these analysis will be

done in R


If you are doing this yourself you will probably need guidance from a well 
crafted monograph. Quite a few are listed at


http://www.r-project.org/doc/bib/R-books.html


HTH,

Chuck




Harrell, Frank E wrote:


1Rnwb wrote:

Hello R gurus,

I am biologist doing biomarker research and I have a data set where I
have 6
proteins and close to 3000 samples, i have to look for differences
between
disease(Y) and controls(N) along with genetic risk, genotypes, sex and
other
demographic info available. however i do not know any of the statistics
to
do the adjustment for sex, age, genotype, genetic risk. I have been
reading
in papers where the authors are talking about adjusting for age, sex,
genotype, genetic risk. The CDC website suggests for adjusting the age
using
the weights, but I am not sure as this would apply to my data. one
website
says that if the distribution is not equal then one has to model sex, age
and other demographic parameters as co-variates. I would appreciate if
someone can help me to understand this more clearly and provide
directions
on modeling these to do my analysis. I am attaching a sample data file
with
this post. Thanks
http://www.nabble.com/file/p24534963/Sample%2Bdata.csv Sample+data.csv


If the only clinical variables you are adjusting for are age and sex
this analysis will be misleading at best.

Frank

--
Frank E Harrell Jr   Professor and Chair   School of Medicine
  Department of Biostatistics   Vanderbilt University

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R-help@r-project.org mailing list
https://stat.ethz.ch/mailman/listinfo/r-help
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http://www.R-project.org/posting-guide.html
and provide commented, minimal, self-contained, reproducible code.




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Charles C. Berry(858) 534-2098
Dept of Family/Preventive Medicine
E mailto:cbe...@tajo.ucsd.edu   UC San Diego
http://famprevmed.ucsd.edu/faculty/cberry/  La Jolla, San Diego 92093-0901

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and provide commented, minimal, self-contained, reproducible code.