As a lifetime smoker, that has quit many times, (this time hopefully for good!) I'd say it is BEST not to smoke while hunting! But as non-smokers will tell you, If you smoked before hunting you will still smell like smoke for hours!
That said, I've done it both ways, I have had to put down a cigarette to shoot more than once! I've also seen them spook!
Sometimes they are curious about the smell of tobacco!
As your doctor, and others will tell you, it's better not to smoke, for a great number of reasons!