1. a Department of Medicine, Division of Global Public Health, School of Medicine , University of California , San Diego , CA , USA
2. b Graduate School of Public Health , San Diego State University , San Diego , CA , USA
3. c Facultad de Medicína y Psicología , Universidad Autónoma de Baja California , Tijuana , Mexico
4. d School of Social Work , University of Southern California , Los Angeles , CA , USA