California Dept. of Health Services Campaign
The top three causes of death in the United States (in order of prevalence):
1) Heart Disease
Smoking significantly contributes to all three causes of death by various mechanisms, but (to be horribly unacademic) I remember from reading our class syllabus that a person exposed to second-hand smoke is 1/3 more likely to develop cardiovascular disease than a non-exposed person. Moreover, we learned that even a few hours of exposure to cigarette smoke led to increased platelet aggregation (or platelet aggression, as I prefer to call it) -- which I found pretty astounding. Smoking is a major health issue tackled by UCSF; please run a PubMed search on Dr. Stanton Glantz and review his amazing research in this area.