I have data with anthropometics (e.g. weight, height, waist cercumference...) and blood samples (e.g. insulin, glucose, triglycerids....) and I use them as outcomes in my lineary regression.

In order to compare these measurements, I have standardarized all variables (and some in sex-specific z-scores, where differences between gender occured)

I have used the egen command to standarize all variables e.g.:

egen float z_insulin = std(finsulin), mean(0) sd(1)

egen float z_gluc0 = std(fglucose) if sex==0, mean(0) sd(1)

egen float z_gluc1 = std(fglucose) if sex==1, mean(0) sd(1)



Now I want to combine these 3 standardarized variables into 1 new combined standarized variable (z_insu_gluco) and i have tried this command:

egen float z_insu_gluc = std(z_insulin, z_gluc0, z_gluc1), mean(0) sd(1)

stata gives an error: z_insulin, z_gluc0, z_gluc1 invalid name

then i have tried without comma separation and the error is: z_insulinz_gluc0z_gluc1 not found.


How do I correctly combine these 3 variables into a new standarized variable?


Thanks