Creating a time variable using age as a time scale

[hejhejehej]

The time variable must include the time for the end of the follow-up (31 dec 2013), regardless of the outcome. I am going to use age as a time-scale. So, the lowest age of age at;

* ADHD diagnosis

* emigration

* death

*  end of follow-up (31 dec 2013)

How am i supposed to create this age-variable? I have the birth -date variable which is the following;  bfoddat_SAS = input( put(X_bfoddat,8.), YYMMDD8.); the date is presented as: YYYYMMDD, and is numeric. However i don't know how to create the age variable? 

*Variable for emigration*;

if MTYP=:'E' then EM=1;

else EM=0;

mig_year= (SUBSTR(MDATUM,1,4));

mig_year_num =input(mig_year,4.);

age_mig=(mig_year_num-bfodar);

*variabel for death*;

 bfoddat_SAS = input( put(X_bfoddat,8.), YYMMDD8.);

  dodsdatum_SAS= input (put(X_dodsdatum, 8.),YYMMDD8.);

if dodsdatum_SAS ne . then  age_dod=INT(YRDIF(bfoddat_SAS,dodsdatum_SAS,'actual'));

[PaigeMiller]

How am i supposed to create this age-variable? I have the birth -date variable which is the following;  bfoddat_SAS = input( put(X_bfoddat,8.), YYMMDD8.);

Wow, this is confusing. You want the years (age) between this bfoddat_SAS variable and December 31, 2013? You have not stated that explicitly. Is that the question? Or have I misunderstood completely?

Side comment: there's really no point is adding _SAS to a variable name, every variable you use is a SAS variable. Save yourself some typing and save yourself the possibility of typographical errors by not adding _SAS to variable names.