In one of your original posts you claimed it did. Therefore my question remains legitimate. If nicotine is the reason for the hindering of bone healing, why are they only looking at one source of nicotine. Nicotine is nicotine is nicotine whether it comes from tobacco, tomatoes, peppers, eggplant, artichokes, or nicotine patches.
To determine that it is ONLY nicotine from smoking they would have to rule out any other source of nicotine. I seriously doubt they can find enough control subjects who have never injested any form of nicotinein their life. Therefore they will be unable to pinpoint that the only nicotine cause is the nicotine from tobacco.
If you think all these researchers are incredibly stupid to exclude nicotine containing foods then email them and let us all know the response. Maybe they are all in on a conspiracy.