[1] Univ Calif San Francisco, Dept Med, Div HIV Infect Dis & Global Med, 1001 Potrero Ave,UCSF Mailbox 0874, San Francisco, CA 94143 USA
[2] Univ Calif San Francisco, Dept Epidemiol & Biostat, San Francisco, CA 94143 USA
[3] Univ Calif San Francisco, Dept Med, Div Prevent Sci, San Francisco, CA 94143 USA
[4] Univ Miami, Dept Publ Hlth Sci, Miami, FL USA