[1] Syrian Ctr Tobacco Studies, Aleppo, Syria
[2] Univ Miami, Miller Sch Med, Dept Epidemiol & Publ Hlth, Miami, FL 33136 USA
[3] Florida Int Univ, Dept Epidemiol, Robert Stempel Coll Publ Hlth & Social Work, Miami, FL 33199 USA
[4] Univ Memphis, Sch Publ Hlth, Div Social & Behav Sci, Memphis, TN 38152 USA