[1] Univ Arizona, Coll Med, Dept Family & Community Med, 3950 South Country Club Rd,Suite 330, Tucson, AZ 85714 USA
[2] Univ Arizona, Mel & Enid Zuckerman Coll Publ Hlth, Dept Epidemiol & Biostat, Tucson, AZ 85714 USA
[3] Univ Oklahoma, Hlth Sci Ctr, Stephenson Canc Ctr, Oklahoma Tobacco Res Ctr, Oklahoma City, OK USA
[4] Univ Minnesota, Sch Med, Dept Family Med & Community Hlth, Minneapolis, MN 55455 USA
[5] Univ Memphis, Sch Publ Hlth, Div Social & Behav Sci, Memphis, TN 38152 USA
[6] Univ Minnesota, Sch Med, Dept Family Med & Biobehav Hlth, Duluth, MN 55812 USA