[1] UT Hlth Sci Ctr Houston, Sch Publ Hlth, UT Hlth, Austin Campus,1616 Guadalupe St,Suite 6-300, Austin, TX 78701 USA
[2] Univ Oklahoma, Hlth Sci Ctr, Oklahoma Tobacco Res Ctr, Oklahoma City, OK USA
[3] UT Hlth Sci Ctr Houston, Sch Publ Hlth, UT Hlth, Dept Epidemiol Human Genet & Environm Sci, Austin Campus, Austin, TX 78701 USA
[4] UT Hlth Sci Ctr Houston, Sch Publ Hlth, UT Hlth, Dept Hlth Promot & Behav Sci, Austin Campus, Austin, TX 78701 USA