[1] Massachusetts Gen Hosp, Dept Med, Tobacco Res & Treatment Ctr, Boston, MA 02114 USA
[2] Harvard Univ, Sch Med, Boston, MA USA
[3] Univ Alabama Birmingham, Div Pulm Allergy & Crit Care Med, Birmingham, AL USA
[4] Univ Kansas, Sch Med, Dept Prevent Med & Publ Hlth, Kansas City, KS USA
[5] Kaiser Permanente Ctr Hlth Res, Portland, OR USA
[6] NYU, Sch Med, Div Gen Internal Med, New York, NY USA
[7] Univ Pittsburgh, Sch Med, Div Gen Med, Pittsburgh, PA USA