In the past two decades rates of cigarette smoking have declined; in some countries the declines have been dramatic [1-3]. "In the United States, more than three out of every fi ve adults who were ever cigarette smokers have quit smoking" [4]. Several possible explanations for the declines can be put forth: increased information about the adverse health effects of cigarette smoking [5,6] and exposure to environmental tobacco smoke [7], fewer public places where smoking is permitted, often supported by legislative restriction [8,9], lower levels of smoking initiation and past year use among adolescents and teens [9], increased availability of smoking cessation aids, although less than one-third of people who quit
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