[The Effect of Neighborhood Characteristics and Friends' Smoking Status on the Habitual Smoking Onset in Adolescents].

Friends' smoking status and living in neighborhoods that are more susceptible to smoking increase the risk of habitual smoking. The number of tobacco outlets in the neighborhood enhances the peer effect of adolescent's smoking behavior. Therefore, policies or interventions designed to reduce youth's tobacco use should focus on not only on reducing peer smoking, but also restricting smoking by adults and the number of neighborhood tobacco outlets.