[1] Univ Calif Los Angeles, Dept Community Hlth Sci, 650 Charles E Young Dr South,21-236,Box 951772, Los Angeles, CA 90095 USA
[2] Univ Calif Los Angeles, Ctr Behav & Addict Med, Dept Family Med, Los Angeles, CA USA
[3] Univ Peruana Cayetano Heredia, Unit Epidemiol HIV & STD, Lima, Peru
[4] Univ Calif Los Angeles, Inst Predict Technol, Dept Family Med, Los Angeles, CA USA