[1] Harvard Univ, Sch Med, Massachusetts Gen Hosp, Mongan Inst Hlth Policy, Boston, MA 02114 USA
[2] Harvard Univ, Sch Med, Massachusetts Gen Hosp, Tobacco Res & Treatment Ctr, Boston, MA 02114 USA
[3] Univ So Calif, Keck Sch Med, Dept Prevent Med, Los Angeles, CA 90033 USA
[4] Univ Wisconsin, Dept Med, Ctr Tobacco Res & Intervent, Sch Med & Publ Hlth, Madison, WI USA
[5] Univ Wisconsin, Dept Educ Psychol, Madison, WI 53706 USA
[6] Univ Wisconsin, Dept Human Dev & Family Studies, Madison, WI 53706 USA