Comparison of 2 groups using linear regression

[Glory Ojinnaka]

Good day all.
I'm trying to compare 2 groups of individuals (cases and controls). I want to ascertain if certain factors affect 5 outcomes of interest for these comparative groups. There were 5 outcomes of interest for the cases and controls. Their were 3 predictor variables. i did a bivariate linear regression for each of the outcomes of interest for the cases and the predictor variables. nothing was significant. however, on multivariate linear regression with the 3 predictor variable and one of the outcome of interest for the cases, one of the predictor variables was significant. I then did a multivariate linear regression with the 3 predictor variables and the same outcome of interest for the control, nothing was significant.
My question is, can regression analysis be done separately for 2 groups (cases and controls) and compared based on the output. If not, how should it be done using stata.
Thank you

[George Ford]

Is this panel or cross section?

No reason to separate the regression. You've got a cases dummy.

sysuse auto, clear

** foreign is treatment

eststo e1: reg mpg foreign gear_ratio length displacement
eststo e2: reg weight foreign gear_ratio length displacement
eststo e3: reg price foreign gear_ratio length displacement
eststo e4: reg turn foreign gear_ratio length displacement
eststo e5: reg trunk foreign gear_ratio length displacement
suest e1 e2 e3 e4 e5 , vce(robust)