All I know is that nicotine interferes with estrogen metabolism when taken orally because it induces (increases) those enzymes in the digestive tract (and liver, I think) that metabolize estrogen, therefore reducing the concentration of estradiol in the blood, by a lot! In one study, those who smoked had 5 times less the concentrations of those who didn't, when on oral estrogen (not transdermal).
Good luck on quitting smoking, I know how hard it is, being a former smoker and my mom is on the patch too, as we speak. I also quit when I started HRT.