1. Department of Community Health Systems, School of Nursing, University of California San Francisco, CA, USA
2. Center for Public Health Research, San Francisco Department of Public Health, CA, USA
3. Center for AIDS Prevention Studies (CAPS), Division of Prevention Science, University of California San Francisco, CA, USA
4. Department of Biostatistics and Epidemiology, School of Public Health, Rutgers University, Piscataway, NJ, USA