[1] Kaiser Permanente, Res & Evaluat Dept, Pasadena, CA 91188 USA
[2] Kaiser Permanente, Ctr Hlth Res, Portland, OR USA
[3] Harvard Univ, Massachusetts Gen Hosp, Sch Med, Tobacco Res & Treatment Ctr, Cambridge, MA 02138 USA
[4] Harvard Pilgrim Hlth Care, Boston, MA USA
[5] HealthPartners Res Fdn, Minneapolis, MN USA
[6] Kaiser Permanente, Div Res, Oakland, CA USA
[7] Kaiser Permanente, Aurora, CO USA
[8] Univ Massachusetts, Sch Med, Worcester, MA 01605 USA
[9] Meyers Primary Care Inst, Fallon Healthcare Syst, Worcester, MA 01605 USA