st: logistic regression and interpreting trend across two time points

[Ameya Bondre <ameyabondre.jhsph@gmail.com>]

Hello,

I am studying the change in malnutrition as a response to the change
in prevalence of exclusive breastfeeding (and a few other covariates),
from 2009 to 2011.

Both the 2009 and 2011 data are cross-sectional and independent.
During both rounds of data collection, each respondent is a mother
with a child 6-24 months of age. The study involves evaluating the
sustenance of program activities in 2011, two years after the program
ended in 2009.

The data set that I am using has these binary variables - (endline =
2009 and followup = 2011)

 underwt_endline - child measured underweight at 2009 (yes/no)
 underwt_followup - child measured underweight at 2011 (yes/no)
 exclbf_endline - child exclusively breastfed as told by mother (yes/no)
 exclbf_followup - child exclusively breastfed as told by mother (yes/no)

There are other similar predictors but for this email, I am limiting
it to just one predictor.

I am not able perform a logistic regression here, that is
interpretable. I have the absolute percentages for these indicators
for both 2009 and 2011:

Prevalence of Exclusive breastfeeding increased from 30% in 2009 to 47% in 2011.
Prevalebce of Underweight decreased from 40% in 2009 to 33% in 2011.

My question is - How can we test for the association between the
percentage change in prevalence of underweight and the percentage
change in prevalence of exclusive breastfeeding, between 2009 and
2011? Can it be done through logistic regression?

Thank you,
Ameya Bondre
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