# Survival analysis using random regression

From: jozzeman <asremlforum_at_VSNI.CO.UK>
Date: Fri, 16 Oct 2009 01:19:42 +0100

Hi,

I'm trying to analyse survival data using a random regression model, but I have some problems interpreting the results. The data structure in the data file is as follows:

ID father mother GDP1 Tank GDP2 day SR
A440 1 3 0.8 1 0.2 1 1
A440 1 3 0.8 1 0.2 2 1
A440 1 3 0.8 1 0.2 3 0
: : : : : : : :
: : : : : : : :
A440 1 3 0.8 2 0.2 52 0
B550 1 3 0.5 2 0.4 1 1
B550 1 3 0.5 2 0.4 2 1

Reading the data is as follows:

Survival analysis
ID !P
father
mother
GDP1 !m-9.9 # average daily gain before challenge to disease
Tank # 2 levels
GDP2 !m-9.9 # average daily gain after challenge to disease
day # days of challenge tests (from 1 to 52)
SR # survival score at a given day (1 or 0 depending if individual
is alive or dead in a specific day)
sr2.txt !ALPHA !REPEAT
sr2.txt !NODISPLAY !MVINCLUDE !SKIP 1 !maxiter=500

I started fitting the follow model:

SR ~mu pol(day,1)*Tank !r pol(day,1).mother !f mv
0 1 1

pol(day,1).mother 2
pol(day,1) 0 US .1 .01 1 !GP
mother

I am interested in estimating the genetic variance of the family (full sibs) this is why I am including only the random effect associated with mother effect.

Am I in the right way?

Can I use !BINOMIAL and !LOGIT qualifiers in the model in order to take account the binary nature of the trait?

How can I estimate heritabilities for SR?

How can I fit a multivariate analysis for estimating the genetic correlation between SR and GDP2?

I would appreciate very much any suggestions or comments about the coding for the analysis.