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* File			    HALCyon cortisol syntax_HCS.do
* BY				Mike Gardner, University of Bristol
* FOR				HALCyon cross-cohort collaboration (funded by the New Dynamics of Ageing (RES-353-25-0001))
* DATASET			Hertfordshire Cohort Study (HCS)
* Date Created 		26/03/2010
* last modified	    02/08/2010

* PURPOSE			Cleans and derives cortisol variables (at wave 1)
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set more off

sum cortisolnmoll, detail
hist cortisolnmoll
**Distribution isn't skewed and appears normal, hence no need to log normal transform

**CORTISOL
**Omit those on oral (fqdrgh10), nasal (fqdrgo1) and topical (fqdrgd1) corticosteroids
sum cortisolnmoll
replace cortisolnmoll=. if(fqdrgh10==1)
replace cortisolnmoll=. if(fqdrgo1==1)
replace cortisolnmoll=. if(fqdrgd1==1)
sum cortisolnmoll


**Blood samples were taken at wave 1 clinic 1999-2004
**rename cortisol, zscore and put into quartiles
rename cortisolnmoll cortisol_w1c
label variable cortisol_w1c "Cortisol at wave 1 clinic"
zscore cortisol_w1c
xtile cortquart=cortisol_w1c, nq(4)
table cortquart, c(n cortisol_w1c min cortisol_w1c max cortisol_w1c)
xtile cortbin=cortisol_w1c, nq(2)
table cortbin, c(n cortisol_w1c min cortisol_w1c max cortisol_w1c)