Consider that maybe it isn't the tobacco itself that is causing the problems but perhaps the chemicals being used to treat if (ie pesticides). The Navajo have been smoking tobacco for centurie--particuliarly medicine men. Of course, their tobacco is organic and I don't recall smoke related heart disease as a primary concern for Navajo health. I think it's obesity and diabetes actually.

Stephanie

In every man there is something wherein I may learn of him, and in that I am his pupil.--Ralph Waldo Emerson