Simply add your confounders into the model.

Well it is a little more complicated than that. See the attached paper. Best wishes, David Booth

Thank u all for ur guidance

To me, there are two conceptions from the word control:

- control its changes (because of interrelations -between confounders and other IVs- it is almost impossible), or

- control its misleading effects on models (adding to the model is enough)

Thank you Respected Babak sir