1. Faculty of Social Work, Centre for Applied Social Research, University of Toronto, Toronto, Ontario, Canada.
2. Center for Community Health, Neuropsychiatric Institute, University of California, Los Angeles, Los Angeles, California.
3. Los Angeles Country Health Department, Division of Sexually Transmitted Disease, Los Angeles, California.
4. Department of Medicine, Division of Digestive Diseases/UCLA AIDS Institute, University of California, Los Angeles, Los Angeles, California.