1. a San Francisco Department of Public Health , San Francisco , CA , USA
2. b Department of Epidemiology and Biostatistics , University of California , San Francisco , CA , USA
3. c Department of Natural Resources , University of California , Berkeley , CA , USA
4. d AIDS Health Project , University of California San Francisco , San Francisco , CA , USA
5. e Department of Psychiatry , University of California San Francisco , San Francisco , CA , USA