since/for ('Since how long you have been suffering in this disease' vs 'For how)

hi,

which line is correct.

since how long you have been suffering in this disease.

or

for how long you have been suffering in this disease.thanks

Hi,

It would be simplest to say: How long have you been suffering from this disease? If you did want to add to that, you could say ‘For how long …’ but that isn’t necessary here.

Alan

Thank you sir.